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www.sciencedirect.com/book/9780128199145/earth-as-an-evolving-planetary-system
Asteroids are small planetary bodies, most of which revolve about the Sun in an orbit between Mars and Jupiter (Taylor, 1992; DeMeo and Carry, 2014). Of the 10,000 or so known asteroids, most occur between 2 and 3 AU from the Sun (Fig. 10.31). The total mass of the asteroid belt is only about 5% of that of the Moon. Only a few large asteroids are recognized, the largest of which is Ceres with a diameter of 933 km. Most asteroids are < 100 km in diameter and there is a high frequency with diameters of 20–30 km.
Three main groups of asteroids are recognized:
(1) the Near-Earth asteroids (Apollo, Aten, and Amor classes), some of which have orbits that cross that of Earth;
(2) the main belt asteroids; and
(3) the Trojans, revolving in the orbit of Jupiter.
Most meteorites arriving on Earth are coming from the Apollo asteroids.
The orbital gaps where no asteroids occur in the asteroid belt (for instance at 3.8 and 2.1 AU, Fig. 10.31) appear to reflect orbital perturbations caused by resonances in the gravity field of Jupiter.
In terms of spectral studies, asteroids vary significantly in composition (Table 10.4), and some can be matched to meteorite groups. Within the asteroid belt, there is a zonal arrangement that reflects chemical composition. S, C, P, and D asteroid classes occupy successive rings outward in the belt, whereas M types predominate near the middle, and B and F types near the outer edge. The broad pattern is that fractionated asteroids dominate in the inner part of the belt, and the low-albedo primitive types (class C) occur only in the outer portions of the belt. Thus asteroids inward of 2 AU are igneous asteroids, and the proportion of igneous to primitive asteroids decreases outward such that by 3.5 AU, there are no igneous types represented.
Although asteroids are continually colliding with each other as indicated by their angular and irregular shapes, the remarkable compositional zonation in the asteroid belt indicates that mixing and stirring in the belt must be relatively minor.
Three main groups of asteroids are recognized:
(1) the Near-Earth asteroids (Apollo, Aten, and Amor classes), some of which have orbits that cross that of Earth;
(2) the main belt asteroids; and
(3) the Trojans, revolving in the orbit of Jupiter.
Most meteorites arriving on Earth are coming from the Apollo asteroids.
The orbital gaps where no asteroids occur in the asteroid belt (for instance at 3.8 and 2.1 AU, Fig. 10.31) appear to reflect orbital perturbations caused by resonances in the gravity field of Jupiter.
In terms of spectral studies, asteroids vary significantly in composition (Table 10.4), and some can be matched to meteorite groups. Within the asteroid belt, there is a zonal arrangement that reflects chemical composition. S, C, P, and D asteroid classes occupy successive rings outward in the belt, whereas M types predominate near the middle, and B and F types near the outer edge. The broad pattern is that fractionated asteroids dominate in the inner part of the belt, and the low-albedo primitive types (class C) occur only in the outer portions of the belt. Thus asteroids inward of 2 AU are igneous asteroids, and the proportion of igneous to primitive asteroids decreases outward such that by 3.5 AU, there are no igneous types represented.
Although asteroids are continually colliding with each other as indicated by their angular and irregular shapes, the remarkable compositional zonation in the asteroid belt indicates that mixing and stirring in the belt must be relatively minor.
From Wikipedia, the free encyclopedia
The Amor asteroid group compared to the orbits of the terrestrial planets of the Solar System.
Mars (M)
Mars trojans
Venus (V)
Mercury (H) Sun
Amor asteroids
Earth (E)
The Amor asteroids are a group of near-Earth asteroids named after the archetype object 1221 Amor /ˈeɪmɔːr/. The orbital perihelion of these objects is close to, but greater than, the orbital aphelion of Earth (i.e., the objects do not cross Earth's orbit),[1] with most Amors crossing the orbit of Mars. The Amor asteroid 433 Eros was the first asteroid to be orbited and landed upon by a robotic space probe (NEAR Shoemaker).
Definition
Amor asteroid Eros visited by NEAR Shoemaker in 2000
The orbital characteristics that define an asteroid as being in the Amor group are:[2]
The orbital period is greater than one year; i.e., the orbital semi-major axis (a) is greater than 1.0 AU (a > 1.0 AU);
The orbit does not cross that of Earth; i.e., the orbital perihelion (q) is greater than Earth's orbital aphelion (q > 1.017 AU);
The object is a near-Earth object (NEO); i.e., q < 1.3 AU.
Populations
As of 2023 there are 11,232 known Amor asteroids. Of those objects, 1275 are numbered and 80 are named.[3]
Outer Earth-grazer asteroids
An outer Earth-grazer asteroid is an asteroid that is normally beyond Earth's orbit, but which can get closer to the Sun than Earth's aphelion (1.0167 AU), and not closer than Earth's perihelion (0.9833 AU); i.e., the asteroid's perihelion is between Earth's perihelion and aphelion. Outer Earth-grazer asteroids are split between Amor and Apollo asteroids. Using the definition of Amor asteroids above, "Earth grazers" that never get closer to the Sun than Earth does (at any point along its orbit) are Amors, whereas those that do are Apollos.
Potentially hazardous asteroids
To be considered a potentially hazardous asteroid (PHA), an object's orbit must, at some point, come within 0.05 AU of Earth's orbit, and the object itself must be sufficiently large/massive to cause significant regional damage if it impacted Earth.[4] Most PHAs are either Aten asteroids or Apollo asteroids (and thus have orbits that cross the orbit of Earth), but approximately one tenth of PHAs are Amor asteroids. A potentially hazardous Amor asteroid therefore must have a perihelion of less than 1.05 AU. Approximately 20% of the known Amors meet this requirement, and about a fifth of those are PHAs. The fifty known Amor PHAs include the named objects 2061 Anza, 3122 Florence, 3908 Nyx, and 3671 Dionysus.
Lists
For a list of articles about Amor asteroids, see Category:Amor asteroids.
Prominent Amor asteroids
Name Year Discoverer Refs
3908 Nyx 1980 Hans-Emil Schuster MPC · JPL · LCDB
1221 Amor 1932 Eugène Delporte MPC · JPL · LCDB
1036 Ganymed 1924 Walter Baade MPC · JPL · LCDB
887 Alinda 1918 Max Wolf MPC · JPL · LCDB
719 Albert 1911 Johann Palisa MPC · JPL · LCDB
433 Eros 1898 Gustav Witt MPC · JPL · LCDB
Named Amor asteroids
This is a non-static list of named Amor asteroids.[5]
Designation Prov. designation
433 Eros 1898 DQ
719 Albert 1911 MT
887 Alinda 1918 DB
1036 Ganymed 1924 TD
1221 Amor 1932 EA1
1580 Betulia 1950 KA
1627 Ivar 1929 SH
1915 Quetzalcoatl 1953 EA
1916 Boreas 1953 RA
1917 Cuyo 1968 AA
1943 Anteros 1973 EC
1980 Tezcatlipoca 1950 LA
2059 Baboquivari 1963 UA
2061 Anza 1960 UA
2202 Pele 1972 RA
2368 Beltrovata 1977 RA
2608 Seneca 1978 DA
3102 Krok 1981 QA
3122 Florence 1981 ET3
3199 Nefertiti 1982 RA
3271 Ul 1982 RB
3288 Seleucus 1982 DV
3352 McAuliffe 1981 CW
3551 Verenia 1983 RD
3552 Don Quixote 1983 SA
Designation Prov. designation
3553 Mera 1985 JA
3671 Dionysus 1984 KD
3691 Bede 1982 FT
3757 Anagolay 1982 XB
3908 Nyx 1980 PA
3988 Huma 1986 LA
4055 Magellan 1985 DO2
4401 Aditi 1985 TB
4487 Pocahontas 1987 UA
4503 Cleobulus 1989 WM
4947 Ninkasi 1988 TJ1
4954 Eric 1990 SQ
4957 Brucemurray 1990 XJ
5324 Lyapunov 1987 SL
5332 Davidaguilar 1990 DA
5370 Taranis 1986 RA
5620 Jasonwheeler 1990 OA
5653 Camarillo 1992 WD5
5751 Zao 1992 AC
5797 Bivoj 1980 AA
5863 Tara 1983 RB
5869 Tanith 1988 VN4
5879 Almeria 1992 CH1
6050 Miwablock 1992 AE
6456 Golombek 1992 OM
Designation Prov. designation
6569 Ondaatje 1993 MO
7088 Ishtar 1992 AA
7336 Saunders 1989 RS1
7358 Oze 1995 YA3
7480 Norwan 1994 PC
8013 Gordonmoore 1990 KA
8034 Akka 1992 LR
8709 Kadlu 1994 JF1
9172 Abhramu 1989 OB
9950 ESA 1990 VB
11284 Belenus 1990 BA
13553 Masaakikoyama 1992 JE
15745 Yuliya 1991 PM5
15817 Lucianotesi 1994 QC
16064 Davidharvey 1999 RH27
16912 Rhiannon 1998 EP8
18106 Blume 2000 NX3
20460 Robwhiteley 1999 LO28
21088 Chelyabinsk 1992 BL2
52387 Huitzilopochtli 1993 OM7
65803 Didymos 1996 GT
96189 Pygmalion 1991 NT3
154991 Vinciguerra 2005 BX26
162011 Konnohmaru 1994 AB1
164215 Doloreshill 2004 MF6
Designation Prov. designation
189011 Ogmios 1997 NJ6
452307 Manawydan 1997 XV11
481984 Cernunnos 2009 KL2
See also
List of Amor asteroid records
Apollo asteroid
Aten asteroid
Atira asteroid
Alinda asteroid
Arjuna asteroid
List of minor planets
References
"Amor asteroid". astronomy encyclopedia. Созвездия.ру. Retrieved 2018-12-26.
"NEO Groups". NASA/JPL Near-Earth Object Program Office. Archived from the original on 2002-02-02. Retrieved 2012-06-04.
"Small-Body Database Query". Solar System Dynamics - Jet Propulsion Laboratory. NASA - California Institute of Technology. Retrieved 2023-02-01.
"List Of The Potentially Hazardous Asteroids (PHAs)". The International Astronomical Union Minor Planet Center. IAU - Minor Planet Center. Retrieved 2019-04-03.
This page was last edited on 15 March 2023,
The Amor asteroid group compared to the orbits of the terrestrial planets of the Solar System.
Mars (M)
Mars trojans
Venus (V)
Mercury (H) Sun
Amor asteroids
Earth (E)
The Amor asteroids are a group of near-Earth asteroids named after the archetype object 1221 Amor /ˈeɪmɔːr/. The orbital perihelion of these objects is close to, but greater than, the orbital aphelion of Earth (i.e., the objects do not cross Earth's orbit),[1] with most Amors crossing the orbit of Mars. The Amor asteroid 433 Eros was the first asteroid to be orbited and landed upon by a robotic space probe (NEAR Shoemaker).
Definition
Amor asteroid Eros visited by NEAR Shoemaker in 2000
The orbital characteristics that define an asteroid as being in the Amor group are:[2]
The orbital period is greater than one year; i.e., the orbital semi-major axis (a) is greater than 1.0 AU (a > 1.0 AU);
The orbit does not cross that of Earth; i.e., the orbital perihelion (q) is greater than Earth's orbital aphelion (q > 1.017 AU);
The object is a near-Earth object (NEO); i.e., q < 1.3 AU.
Populations
As of 2023 there are 11,232 known Amor asteroids. Of those objects, 1275 are numbered and 80 are named.[3]
Outer Earth-grazer asteroids
An outer Earth-grazer asteroid is an asteroid that is normally beyond Earth's orbit, but which can get closer to the Sun than Earth's aphelion (1.0167 AU), and not closer than Earth's perihelion (0.9833 AU); i.e., the asteroid's perihelion is between Earth's perihelion and aphelion. Outer Earth-grazer asteroids are split between Amor and Apollo asteroids. Using the definition of Amor asteroids above, "Earth grazers" that never get closer to the Sun than Earth does (at any point along its orbit) are Amors, whereas those that do are Apollos.
Potentially hazardous asteroids
To be considered a potentially hazardous asteroid (PHA), an object's orbit must, at some point, come within 0.05 AU of Earth's orbit, and the object itself must be sufficiently large/massive to cause significant regional damage if it impacted Earth.[4] Most PHAs are either Aten asteroids or Apollo asteroids (and thus have orbits that cross the orbit of Earth), but approximately one tenth of PHAs are Amor asteroids. A potentially hazardous Amor asteroid therefore must have a perihelion of less than 1.05 AU. Approximately 20% of the known Amors meet this requirement, and about a fifth of those are PHAs. The fifty known Amor PHAs include the named objects 2061 Anza, 3122 Florence, 3908 Nyx, and 3671 Dionysus.
Lists
For a list of articles about Amor asteroids, see Category:Amor asteroids.
Prominent Amor asteroids
Name Year Discoverer Refs
3908 Nyx 1980 Hans-Emil Schuster MPC · JPL · LCDB
1221 Amor 1932 Eugène Delporte MPC · JPL · LCDB
1036 Ganymed 1924 Walter Baade MPC · JPL · LCDB
887 Alinda 1918 Max Wolf MPC · JPL · LCDB
719 Albert 1911 Johann Palisa MPC · JPL · LCDB
433 Eros 1898 Gustav Witt MPC · JPL · LCDB
Named Amor asteroids
This is a non-static list of named Amor asteroids.[5]
Designation Prov. designation
433 Eros 1898 DQ
719 Albert 1911 MT
887 Alinda 1918 DB
1036 Ganymed 1924 TD
1221 Amor 1932 EA1
1580 Betulia 1950 KA
1627 Ivar 1929 SH
1915 Quetzalcoatl 1953 EA
1916 Boreas 1953 RA
1917 Cuyo 1968 AA
1943 Anteros 1973 EC
1980 Tezcatlipoca 1950 LA
2059 Baboquivari 1963 UA
2061 Anza 1960 UA
2202 Pele 1972 RA
2368 Beltrovata 1977 RA
2608 Seneca 1978 DA
3102 Krok 1981 QA
3122 Florence 1981 ET3
3199 Nefertiti 1982 RA
3271 Ul 1982 RB
3288 Seleucus 1982 DV
3352 McAuliffe 1981 CW
3551 Verenia 1983 RD
3552 Don Quixote 1983 SA
Designation Prov. designation
3553 Mera 1985 JA
3671 Dionysus 1984 KD
3691 Bede 1982 FT
3757 Anagolay 1982 XB
3908 Nyx 1980 PA
3988 Huma 1986 LA
4055 Magellan 1985 DO2
4401 Aditi 1985 TB
4487 Pocahontas 1987 UA
4503 Cleobulus 1989 WM
4947 Ninkasi 1988 TJ1
4954 Eric 1990 SQ
4957 Brucemurray 1990 XJ
5324 Lyapunov 1987 SL
5332 Davidaguilar 1990 DA
5370 Taranis 1986 RA
5620 Jasonwheeler 1990 OA
5653 Camarillo 1992 WD5
5751 Zao 1992 AC
5797 Bivoj 1980 AA
5863 Tara 1983 RB
5869 Tanith 1988 VN4
5879 Almeria 1992 CH1
6050 Miwablock 1992 AE
6456 Golombek 1992 OM
Designation Prov. designation
6569 Ondaatje 1993 MO
7088 Ishtar 1992 AA
7336 Saunders 1989 RS1
7358 Oze 1995 YA3
7480 Norwan 1994 PC
8013 Gordonmoore 1990 KA
8034 Akka 1992 LR
8709 Kadlu 1994 JF1
9172 Abhramu 1989 OB
9950 ESA 1990 VB
11284 Belenus 1990 BA
13553 Masaakikoyama 1992 JE
15745 Yuliya 1991 PM5
15817 Lucianotesi 1994 QC
16064 Davidharvey 1999 RH27
16912 Rhiannon 1998 EP8
18106 Blume 2000 NX3
20460 Robwhiteley 1999 LO28
21088 Chelyabinsk 1992 BL2
52387 Huitzilopochtli 1993 OM7
65803 Didymos 1996 GT
96189 Pygmalion 1991 NT3
154991 Vinciguerra 2005 BX26
162011 Konnohmaru 1994 AB1
164215 Doloreshill 2004 MF6
Designation Prov. designation
189011 Ogmios 1997 NJ6
452307 Manawydan 1997 XV11
481984 Cernunnos 2009 KL2
See also
List of Amor asteroid records
Apollo asteroid
Aten asteroid
Atira asteroid
Alinda asteroid
Arjuna asteroid
List of minor planets
References
"Amor asteroid". astronomy encyclopedia. Созвездия.ру. Retrieved 2018-12-26.
"NEO Groups". NASA/JPL Near-Earth Object Program Office. Archived from the original on 2002-02-02. Retrieved 2012-06-04.
"Small-Body Database Query". Solar System Dynamics - Jet Propulsion Laboratory. NASA - California Institute of Technology. Retrieved 2023-02-01.
"List Of The Potentially Hazardous Asteroids (PHAs)". The International Astronomical Union Minor Planet Center. IAU - Minor Planet Center. Retrieved 2019-04-03.
This page was last edited on 15 March 2023,
From Wikipedia, the free encyclopedia
Location of the Apollo asteroids compared to the orbits of the terrestrial planets of the Solar System
Mars (M)
Venus (V)
Mercury (H) Sun
Apollo asteroids
Earth (E)
The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, discovered by German astronomer Karl Reinmuth in the 1930s. They are Earth-crossing asteroids that have an orbital semi-major axis greater than that of the Earth (a > 1 AU) but perihelion distances less than the Earth's aphelion distance (q < 1.017 AU).[1][2]
As of February 2023, the number of known Apollo asteroids is 17,540, making the class the largest group of near-Earth objects (cf. the Aten, Amor and Atira asteroids),[3] of which 1,571 are numbered (asteroids are not numbered until they have been observed at two or more oppositions), and 1,976 are identified as potentially hazardous asteroids.[4]
The closer their semi-major axis is to Earth's, the less eccentricity is needed for the orbits to cross. The Chelyabinsk meteor, that exploded over the city of Chelyabinsk in the southern Urals region of Russia on February 15, 2013, injuring an estimated 1,500 people with flying glass from broken windows, was an Apollo-class asteroid.[5][6]
List
The largest known Apollo asteroid is 1866 Sisyphus, with a diameter of about 8.5 km. Examples of known Apollo asteroids include:
Designation Year Discoverer/First observed (A) Ref
2019 SU3 2019 ATLAS-HKO MPC
2016 WF9 2016 NEOWISE MPC
2014 JO25 2014 CSS MPC
2013 FW13 2013 CSS MPC
2013 RH74 2013 CSS MPC
2011 MD 2011 LINEAR MPC(B)
2011 EO40 2011 CSS–Mount Lemmon Survey MPC
2010 AL30 2010 LINEAR MPC
(529366) 2009 WM1 2009 CSS MPC
2009 DD45 2009 Siding Spring Observatory, Australia MPC
(386454) 2008 XM 2008 LINEAR List
2008 TC3 2008 CSS MPC
2008 FF5 2008 CSS–Mount Lemmon Survey MPC
2007 VK184 2007 CSS MPC
2007 TU24 2007 CSS MPC
2007 WD5 2007 CSS MPC
2007 OX 2007 CSS–Mount Lemmon Survey MPC
(277810) 2006 FV35 2006 Spacewatch List
(394130) 2006 HY51 2006 LINEAR List
(292220) 2006 SU49 2006 Spacewatch List
(308635) 2005 YU55 2005 R. S. McMillan, Steward Observatory, Kitt Peak, USA List
2005 WY55 2005 Mount Lemmon Survey MPC
2005 HC4 2005 LONEOS MPC
2004 XP14 2004 LINEAR MPC
(374158) 2004 UL 2004 LINEAR List
(357439) 2004 BL86 2004 LINEAR List
(444004) 2004 AS1 2004 LINEAR List
2003 RW11 2003 James Whitney Young MPC
2003 BV35 2003 James Whitney Young MPC
(89958) 2002 LY45 2002 LINEAR List
(179806) 2002 TD66 2002 LINEAR List
54509 YORP 2000 LINEAR List
162173 Ryugu 1999 LINEAR List
(137108) 1999 AN10 1999 LINEAR List
101955 Bennu 1999 LINEAR (Bennu is the target of the OSIRIS-REx mission) List
1998 KY26 1998 Spacewatch MPC
(433953) 1997 XR2 1997 LINEAR List
65803 Didymos 1996 Spacewatch List
69230 Hermes 1937 Karl Reinmuth List
(53319) 1999 JM8 1999 LINEAR List
(52760) 1998 ML14 1998 LINEAR List
(35396) 1997 XF11 1997 Spacewatch List
25143 Itokawa 1998 LINEAR List
(136617) 1994 CC 1994 Spacewatch List
(175706) 1996 FG3 1996 R. H. McNaught, Siding Spring Observatory, Australia List
6489 Golevka 1991 Eleanor F. Helin List
4769 Castalia 1989 Eleanor F. Helin List
4660 Nereus 1982 Eleanor F. Helin List
4581 Asclepius 1989 Henry E. Holt, Norman G. Thomas List
4486 Mithra 1987 Eric Elst, Vladimir Shkodrov List
14827 Hypnos 1986 Carolyn S. Shoemaker, Eugene Merle Shoemaker List
4197 Morpheus 1982 Eleanor F. Helin, Eugene Merle Shoemaker List
4183 Cuno 1959 Cuno Hoffmeister List
4179 Toutatis 1989 Christian Pollas List
4015 Wilson–Harrington 1979 Eleanor F. Helin List
3200 Phaethon 1983 Simon F. Green, John K.Davies / IRAS List
2063 Bacchus 1977 Charles T. Kowal List
1866 Sisyphus 1972 Paul Wild List
1620 Geographos 1951 Albert George Wilson, Rudolph Minkowski List
(29075) 1950 DA 1950 Carl A. Wirtanen List
1566 Icarus 1949 Walter Baade List
1685 Toro 1948 Carl A. Wirtanen List
2101 Adonis 1936 Eugène Joseph Delporte List
1862 Apollo 1932 Karl Reinmuth List
(A) Discoverer:
A discoverer is determined by the MPC when the object is numbered. For unnumbered bodies, the table gives the "first observer".
LINEAR: Lincoln Near-Earth Asteroid Research
CSS : Catalina Sky Survey
Spacewatch, on Kitt Peak, near Tucson, Arizona[7]
(B) Classification:
2011 MD is classified as Amor, not Apollo asteroid by the MPC
See also
Alinda group
Amor asteroid
Apollo asteroids (category)
Apollo asteroid records
Aten asteroid
List of minor planets
2020 PP1
References
"Near-Earth Object Groups". JPL – NASA. Archived from the original on 2 February 2002. Retrieved 11 November 2016.
Weisstein, Eric. "Apollo Asteroid". Wolfram Research. Retrieved 27 February 2013.
"NEO Discovery Statistics". Archived from the original on 13 May 2004. Retrieved 11 November 2016.
"Small-Body Database Query". Solar System Dynamics - Jet Propulsion Laboratory. NASA - California Institute of Technology. Retrieved 2023-02-01.
Cantor, Matt (26 February 2013). "Scientists figure out Russia meteor's origin". USA Today. Retrieved 11 November 2016.
Jacob Aron (26 February 2013). "Russian meteor traced to Apollo asteroid family". New Scientist. Retrieved 11 November 2016.
This page was last edited on 15 March 2023
Location of the Apollo asteroids compared to the orbits of the terrestrial planets of the Solar System
Mars (M)
Venus (V)
Mercury (H) Sun
Apollo asteroids
Earth (E)
The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, discovered by German astronomer Karl Reinmuth in the 1930s. They are Earth-crossing asteroids that have an orbital semi-major axis greater than that of the Earth (a > 1 AU) but perihelion distances less than the Earth's aphelion distance (q < 1.017 AU).[1][2]
As of February 2023, the number of known Apollo asteroids is 17,540, making the class the largest group of near-Earth objects (cf. the Aten, Amor and Atira asteroids),[3] of which 1,571 are numbered (asteroids are not numbered until they have been observed at two or more oppositions), and 1,976 are identified as potentially hazardous asteroids.[4]
The closer their semi-major axis is to Earth's, the less eccentricity is needed for the orbits to cross. The Chelyabinsk meteor, that exploded over the city of Chelyabinsk in the southern Urals region of Russia on February 15, 2013, injuring an estimated 1,500 people with flying glass from broken windows, was an Apollo-class asteroid.[5][6]
List
The largest known Apollo asteroid is 1866 Sisyphus, with a diameter of about 8.5 km. Examples of known Apollo asteroids include:
Designation Year Discoverer/First observed (A) Ref
2019 SU3 2019 ATLAS-HKO MPC
2016 WF9 2016 NEOWISE MPC
2014 JO25 2014 CSS MPC
2013 FW13 2013 CSS MPC
2013 RH74 2013 CSS MPC
2011 MD 2011 LINEAR MPC(B)
2011 EO40 2011 CSS–Mount Lemmon Survey MPC
2010 AL30 2010 LINEAR MPC
(529366) 2009 WM1 2009 CSS MPC
2009 DD45 2009 Siding Spring Observatory, Australia MPC
(386454) 2008 XM 2008 LINEAR List
2008 TC3 2008 CSS MPC
2008 FF5 2008 CSS–Mount Lemmon Survey MPC
2007 VK184 2007 CSS MPC
2007 TU24 2007 CSS MPC
2007 WD5 2007 CSS MPC
2007 OX 2007 CSS–Mount Lemmon Survey MPC
(277810) 2006 FV35 2006 Spacewatch List
(394130) 2006 HY51 2006 LINEAR List
(292220) 2006 SU49 2006 Spacewatch List
(308635) 2005 YU55 2005 R. S. McMillan, Steward Observatory, Kitt Peak, USA List
2005 WY55 2005 Mount Lemmon Survey MPC
2005 HC4 2005 LONEOS MPC
2004 XP14 2004 LINEAR MPC
(374158) 2004 UL 2004 LINEAR List
(357439) 2004 BL86 2004 LINEAR List
(444004) 2004 AS1 2004 LINEAR List
2003 RW11 2003 James Whitney Young MPC
2003 BV35 2003 James Whitney Young MPC
(89958) 2002 LY45 2002 LINEAR List
(179806) 2002 TD66 2002 LINEAR List
54509 YORP 2000 LINEAR List
162173 Ryugu 1999 LINEAR List
(137108) 1999 AN10 1999 LINEAR List
101955 Bennu 1999 LINEAR (Bennu is the target of the OSIRIS-REx mission) List
1998 KY26 1998 Spacewatch MPC
(433953) 1997 XR2 1997 LINEAR List
65803 Didymos 1996 Spacewatch List
69230 Hermes 1937 Karl Reinmuth List
(53319) 1999 JM8 1999 LINEAR List
(52760) 1998 ML14 1998 LINEAR List
(35396) 1997 XF11 1997 Spacewatch List
25143 Itokawa 1998 LINEAR List
(136617) 1994 CC 1994 Spacewatch List
(175706) 1996 FG3 1996 R. H. McNaught, Siding Spring Observatory, Australia List
6489 Golevka 1991 Eleanor F. Helin List
4769 Castalia 1989 Eleanor F. Helin List
4660 Nereus 1982 Eleanor F. Helin List
4581 Asclepius 1989 Henry E. Holt, Norman G. Thomas List
4486 Mithra 1987 Eric Elst, Vladimir Shkodrov List
14827 Hypnos 1986 Carolyn S. Shoemaker, Eugene Merle Shoemaker List
4197 Morpheus 1982 Eleanor F. Helin, Eugene Merle Shoemaker List
4183 Cuno 1959 Cuno Hoffmeister List
4179 Toutatis 1989 Christian Pollas List
4015 Wilson–Harrington 1979 Eleanor F. Helin List
3200 Phaethon 1983 Simon F. Green, John K.Davies / IRAS List
2063 Bacchus 1977 Charles T. Kowal List
1866 Sisyphus 1972 Paul Wild List
1620 Geographos 1951 Albert George Wilson, Rudolph Minkowski List
(29075) 1950 DA 1950 Carl A. Wirtanen List
1566 Icarus 1949 Walter Baade List
1685 Toro 1948 Carl A. Wirtanen List
2101 Adonis 1936 Eugène Joseph Delporte List
1862 Apollo 1932 Karl Reinmuth List
(A) Discoverer:
A discoverer is determined by the MPC when the object is numbered. For unnumbered bodies, the table gives the "first observer".
LINEAR: Lincoln Near-Earth Asteroid Research
CSS : Catalina Sky Survey
Spacewatch, on Kitt Peak, near Tucson, Arizona[7]
(B) Classification:
2011 MD is classified as Amor, not Apollo asteroid by the MPC
See also
Alinda group
Amor asteroid
Apollo asteroids (category)
Apollo asteroid records
Aten asteroid
List of minor planets
2020 PP1
References
"Near-Earth Object Groups". JPL – NASA. Archived from the original on 2 February 2002. Retrieved 11 November 2016.
Weisstein, Eric. "Apollo Asteroid". Wolfram Research. Retrieved 27 February 2013.
"NEO Discovery Statistics". Archived from the original on 13 May 2004. Retrieved 11 November 2016.
"Small-Body Database Query". Solar System Dynamics - Jet Propulsion Laboratory. NASA - California Institute of Technology. Retrieved 2023-02-01.
Cantor, Matt (26 February 2013). "Scientists figure out Russia meteor's origin". USA Today. Retrieved 11 November 2016.
Jacob Aron (26 February 2013). "Russian meteor traced to Apollo asteroid family". New Scientist. Retrieved 11 November 2016.
This page was last edited on 15 March 2023
From Wikipedia, the free encyclopedia
The Aten group compared to the orbits of the terrestrial planets of the Solar System.
Mars (M)
Venus (V)
Mercury (H) Sun
Aten asteroids
Earth (E)
The Aten asteroids are a dynamical group of asteroids whose orbits bring them into proximity with Earth. By definition, Atens are Earth-crossing asteroids (a < 1.0 AU and Q > 0.983 AU).[1] The group is named after 2062 Aten, the first of its kind, discovered on 7 January 1976 by American astronomer Eleanor Helin at Palomar Observatory. As of 2023, 2,445 Atens have been discovered, of which 256 are numbered, 13 are named, and 101 are classified as potentially hazardous asteroids.[2][3][4]
Description
See also: List of Aten asteroids
See also: Category:Aten asteroids
Aten asteroids are defined by having a semi-major axis (a) of less than 1.0 astronomical unit (AU), the roughly average distance from the Earth to the Sun. They also have an aphelion (Q; furthest distance from the Sun) greater than 0.983 AU.[1] This defines them as Earth-crossing asteroids as the orbit of Earth varies between 0.983 and 1.017 AU.
Asteroids' orbits can be highly eccentric. Nearly all known Aten asteroids have an aphelion greater than 1 AU. Observation of objects inferior to the Earth's orbit is difficult, and this difficulty may contribute to sampling bias in the apparent preponderance of eccentric Atens. Aten asteroids account for only about 7.4% of the known near-Earth asteroid population.[4] Many more Apollo-class asteroids are known than Aten-class asteroids, possibly because of the sampling bias.
The shortest semi-major axis for any known Aten asteroid is 0.580 AU, for object 2016 XK24.[3] The Aten asteroid with the smallest known perihelion is also the one with the highest known eccentricity: (137924) 2000 BD19 has an orbit with an eccentricity of 0.895, which takes it from a perihelion of 0.092 AU, well within Mercury's orbit, to an aphelion of 1.66 AU, which is greater than the semi-major axis of Mars (1.53 AU). For a brief time near the end of 2004, the asteroid 99942 Apophis (then known only by its provisional designation 2004 MN4) apparently posed a threat of impacting Earth in 2029 or 2036, but earlier observations were found that eliminated those possibilities.[5]
NEO types
Definition of NEO subgroups in AU [1] Group q a Q ECA
Amors > 1.017 >1.0 – Red X
Apollos < 1.017 >1.0 – Green tick
Atens – <1.0 > 0.983 Green tick
Atiras – <1.0 < 0.983 Red X
For all NEOs q is < 1.3 AU; The orbit of Earth varies between 0.983 and 1.017 AU
See also
Alinda asteroid
Amor asteroid
Apollo asteroid
Atira asteroid
List of minor planets
References
"NEO Basics". NASA/JPL CNEOS. Retrieved 17 May 2018.
"Small-Body Database Query". Solar System Dynamics - Jet Propulsion Laboratory. NASA - California Institute of Technology. Retrieved 1 February 2023.
"List Of Aten Minor Planets (by perihelion distance)". Minor Planet Center. 17 May 2017. Retrieved 17 May 2017.
"Discovery Statistics – Cumulative Totals". NASA/JPL CNEOS. 16 May 2018. Retrieved 17 May 2018.
This page was last edited on 15 March 2023
The Aten group compared to the orbits of the terrestrial planets of the Solar System.
Mars (M)
Venus (V)
Mercury (H) Sun
Aten asteroids
Earth (E)
The Aten asteroids are a dynamical group of asteroids whose orbits bring them into proximity with Earth. By definition, Atens are Earth-crossing asteroids (a < 1.0 AU and Q > 0.983 AU).[1] The group is named after 2062 Aten, the first of its kind, discovered on 7 January 1976 by American astronomer Eleanor Helin at Palomar Observatory. As of 2023, 2,445 Atens have been discovered, of which 256 are numbered, 13 are named, and 101 are classified as potentially hazardous asteroids.[2][3][4]
Description
See also: List of Aten asteroids
See also: Category:Aten asteroids
Aten asteroids are defined by having a semi-major axis (a) of less than 1.0 astronomical unit (AU), the roughly average distance from the Earth to the Sun. They also have an aphelion (Q; furthest distance from the Sun) greater than 0.983 AU.[1] This defines them as Earth-crossing asteroids as the orbit of Earth varies between 0.983 and 1.017 AU.
Asteroids' orbits can be highly eccentric. Nearly all known Aten asteroids have an aphelion greater than 1 AU. Observation of objects inferior to the Earth's orbit is difficult, and this difficulty may contribute to sampling bias in the apparent preponderance of eccentric Atens. Aten asteroids account for only about 7.4% of the known near-Earth asteroid population.[4] Many more Apollo-class asteroids are known than Aten-class asteroids, possibly because of the sampling bias.
The shortest semi-major axis for any known Aten asteroid is 0.580 AU, for object 2016 XK24.[3] The Aten asteroid with the smallest known perihelion is also the one with the highest known eccentricity: (137924) 2000 BD19 has an orbit with an eccentricity of 0.895, which takes it from a perihelion of 0.092 AU, well within Mercury's orbit, to an aphelion of 1.66 AU, which is greater than the semi-major axis of Mars (1.53 AU). For a brief time near the end of 2004, the asteroid 99942 Apophis (then known only by its provisional designation 2004 MN4) apparently posed a threat of impacting Earth in 2029 or 2036, but earlier observations were found that eliminated those possibilities.[5]
NEO types
Definition of NEO subgroups in AU [1] Group q a Q ECA
Amors > 1.017 >1.0 – Red X
Apollos < 1.017 >1.0 – Green tick
Atens – <1.0 > 0.983 Green tick
Atiras – <1.0 < 0.983 Red X
For all NEOs q is < 1.3 AU; The orbit of Earth varies between 0.983 and 1.017 AU
See also
Alinda asteroid
Amor asteroid
Apollo asteroid
Atira asteroid
List of minor planets
References
"NEO Basics". NASA/JPL CNEOS. Retrieved 17 May 2018.
"Small-Body Database Query". Solar System Dynamics - Jet Propulsion Laboratory. NASA - California Institute of Technology. Retrieved 1 February 2023.
"List Of Aten Minor Planets (by perihelion distance)". Minor Planet Center. 17 May 2017. Retrieved 17 May 2017.
"Discovery Statistics – Cumulative Totals". NASA/JPL CNEOS. 16 May 2018. Retrieved 17 May 2018.
This page was last edited on 15 March 2023
From Wikipedia, the free encyclopedia
The group of Atira (Apohele) asteroids compared to the orbits of the terrestrial planets of the Solar System.
Mars (M)
Venus (V)
Mercury (H) Sun
Atira asteroids
Earth (E)
Atira asteroids /əˈtɪrə/ or Apohele asteroids, also known as interior-Earth objects (IEOs), are asteroids whose orbits are entirely confined within Earth's orbit;[1] that is, their orbit has an aphelion (farthest point from the Sun) smaller than Earth's perihelion (nearest point to the Sun), which is 0.983 astronomical units (AU). Atira asteroids are by far the least numerous group of near-Earth objects, compared to the more populous Aten, Apollo and Amor asteroids.[2]
History
Naming
There is no official name for the class commonly referred as Atira asteroids. The term "Apohele asteroids" was proposed by the discoverers of 1998 DK36,[3] after the Hawaiian word for orbit, from apo [ˈɐpo] 'circle' and hele [ˈhɛlɛ] 'to go'.[4] This was suggested partly because of its similarity to the words aphelion (apoapsis) and helios. Other authors adopted the designation "Inner Earth Objects" (IEOs).[5] Following the general practice to name a new class of asteroids for the first recognized member of that class, which in this case was 163693 Atira, the designation of "Atira asteroids" was largely adopted by the scientific community, including by NASA.[6][1]
Discovery and observation
Their location inside the Earth's orbit makes Atiras very difficult to observe, as from Earth's perspective they are close to the Sun and therefore 'drowned out' by the Sun's overpowering light.[7] This means that Atiras can usually only be seen during twilight.[7] The first documented twilight searches for asteroids inside Earth's orbit were performed by astronomer Robert Trumpler over the early 20th century, but he failed to find any.[7]
The first suspected Atira asteroid was 1998 DK36, which was discovered by David J. Tholen of the Mauna Kea Observatory, but the first to be confirmed as such was 163693 Atira in 2003, discovered by the Arecibo Observatory. As of February 2023, there are 28 known Atiras, two of which are named, eight of which have received a numbered designation, and six of which are potentially hazardous objects.[2][8][9] An additional 127 objects have aphelia smaller than Earth's aphelion (Q = 1.017 AU).[10]
Origins
Most Atira asteroids originated in the asteroid belt and were driven to their current locations as a result of gravitational perturbation, as well as other causes such as the Yarkovsky effect.[7]
Orbits
Atiras do not cross Earth's orbit and are not immediate impact event threats, but their orbits may be perturbed outward by a close approach to either Mercury or Venus and become Earth-crossing asteroids in the future. The dynamics of many Atira asteroids resemble the one induced by the Kozai-Lidov mechanism, which contributes to enhanced long-term orbital stability, since there is no libration of the perihelion.[11][12]
Exploration
A 2017 study published in the journal Advances in Space Research proposed a low-cost space probe be sent to study Atira asteroids, citing the difficulty in observing the group from Earth as a reason to undertake the mission.[13] The study proposed that the mission would be powered by spacecraft electric propulsion and would follow a path designed to flyby as many Atira asteroids as possible. The probe would also attempt to discover new NEO's that may pose a threat to Earth.[13]
Related asteroid groups
ꞌAylóꞌchaxnim asteroids
ꞌAylóꞌchaxnim asteroids, which had been provisionally nicknamed "Vatira" asteroids before the first was discovered,[c] are a subclass of Atiras that orbit entirely interior to the orbit of Venus, aka 0.718 AU.[15] Despite their orbits placing them at a significant distance from Earth, they are still classified as near-Earth objects.[16] Observations suggest that ꞌAylóꞌchaxnim asteroids frequently have their orbits altered into Atira asteroids and vice-versa.[17]
First formally theorised to exist by Sarah Greenstreet, Henry Ngo, and Brett Gladman in 2012,[7] the first and to date only such asteroid found is 594913 ꞌAylóꞌchaxnim,[18][19] which was discovered on 4 January 2020 by the Zwicky Transient Facility. As the archetype, it subsequently gave its name to the class.[15] It has an aphelion of only 0.656 AU, making it the asteroid with the smallest known aphelion.[8][11]
Vulcanoids
Main article: Vulcanoid
No asteroids have yet been discovered to orbit entirely inside the orbit of Mercury (q = 0.307 AU). Such hypothetical asteroids would likely be termed vulcanoids, although the term often refers to asteroids which more specifically have remained in the intra-Mercurian region over the age of the solar system.[14]
Members
The following table lists the known and suspected Atiras as of February 2022. 594913 ꞌAylóꞌchaxnim, due to its unique classification, has been highlighted in pink. The interior planets Mercury and Venus have been included for comparison as grey rows.
List of known and suspected Atiras as of February 2021 (Q < 0.983 AU)[8] Designation Perihelion
(AU) Semi-major axis
(AU) Aphelion
(AU) Eccentricity Inclination
(°) Period
(days) Observation arc
(days) (H) Diameter(A)
(m) Discoverer Ref
Mercury
(for comparison) 0.307 0.3871 0.467 0.2056 7.01 88 NA -0.6 4,879,400 NA
Venus
(for comparison) 0.718 0.7233 0.728 0.0068 3.39 225 NA -4.5 12,103,600 NA
1998 DK36 0.404 0.6923 0.980 0.4160 2.02 210 1 25.0 35 David J. Tholen MPC · JPL
163693 Atira 0.502 0.7410 0.980 0.3222 25.62 233 6601 16.3 4800±500(B) LINEAR List
MPC · JPL
(164294) 2004 XZ130 0.337 0.6176 0.898 0.4546 2.95 177 3564 20.4 300 David J. Tholen List
MPC · JPL
(434326) 2004 JG6 0.298 0.6353 0.973 0.5311 18.94 185 6227 18.5 710 LONEOS List
MPC · JPL
(413563) 2005 TG45 0.428 0.6814 0.935 0.3722 23.33 205 5814 17.6 1,100 Catalina Sky Survey List
MPC · JPL
2013 JX28
(aka 2006 KZ39) 0.262 0.6008 0.940 0.5641 10.76 170 5110 20.1 340 Mount Lemmon Survey
Pan-STARRS MPC · JPL
(613676) 2006 WE4 0.641 0.7848 0.928 0.1829 24.77 254 4995 18.9 590 Mount Lemmon Survey List
MPC · JPL
(418265) 2008 EA32 0.428 0.6159 0.804 0.3050 28.26 177 4794 16.5 1,800 Catalina Sky Survey List
MPC · JPL
(481817) 2008 UL90 0.431 0.6951 0.959 0.3798 24.31 212 4496 18.6 680 Mount Lemmon Survey List
MPC · JPL
2010 XB11 0.288 0.6180 0.948 0.5339 29.89 177 1811 19.9 370 Mount Lemmon Survey MPC · JPL
2012 VE46 0.455 0.7131 0.971 0.3613 6.67 220 2225 20.2 320 Pan-STARRS MPC · JPL
2013 TQ5 0.653 0.7737 0.894 0.1557 16.40 249 2269 19.8 390 Mount Lemmon Survey MPC · JPL
2014 FO47 0.548 0.7522 0.956 0.2712 19.20 238 2779 20.3 310 Mount Lemmon Survey MPC · JPL
2015 DR215 0.352 0.6665 0.981 0.4716 4.08 199 2156 20.4 300 Pan-STARRS MPC · JPL
2017 XA1 0.646 0.8095 0.973 0.2017 17.18 266 1084 21.3 200 Pan-STARRS MPC · JPL
2017 YH
(aka 2016 XJ24) 0.328 0.6343 0.940 0.4825 19.85 185 1127 18.4 740 Spacewatch
ATLAS MPC · JPL
2018 JB3 0.485 0.6832 0.882 0.2904 40.39 206 2037 17.7 1,020 Catalina Sky Survey MPC · JPL
2019 AQ3 0.404 0.5887 0.774 0.3143 47.22 165 2175 17.5 1,120 Zwicky Transient Facility MPC · JPL
2019 LF6 0.317 0.5554 0.794 0.4293 29.51 151 796 17.3 1,230 Zwicky Transient Facility MPC · JPL
594913 ꞌAylóꞌchaxnim 0.457 0.5554 0.654 0.1770 15.87 151 609 16.2 1500+1100
−600 Zwicky Transient Facility MPC · JPL
2020 HA10 0.692 0.8196 0.947 0.1552 49.65 271 3248 18.9 590 Mount Lemmon Survey MPC · JPL
2020 OV1 0.476 0.6376 0.800 0.2541 32.58 186 1169 18.9 590 Zwicky Transient Facility MPC · JPL
2021 BS1 0.396 0.5984 0.800 0.3377 31.73 169 46 18.5 710 Zwicky Transient Facility MPC · JPL
2021 LJ4 0.416 0.6748 0.933 0.3834 9.83 202 5 20.1 340 Scott S. Sheppard MPC · JPL
2021 PB2 0.610 0.7174 0.825 0.1501 24.83 222 3392 18.8 620 Zwicky Transient Facility MPC · JPL
2021 PH27 0.133 0.4617 0.790 0.7117 31.93 115 1515 17.7 1,020 Scott S. Sheppard MPC · JPL
2021 VR3 0.313 0.5339 0.755 0.4138 18.06 143 1012 18.0 890 Zwicky Transient Facility MPC · JPL
2022 BJ8 0.590 0.7852 0.981 0.2487 15.83 254 102 19.6 430 Kitt Peak-Bok MPC · JPL
2023 EL 0.579 0.7676 0.956 0.2453 13.63 246 9 18.9 580 Scott S. Sheppard MPC · JPL
2023 EY2 0.398 0.6033 0.809 0.3978 35.55 171 6 19.9 370 Kitt Peak-Bok MPC · JPL
(A) All diameter estimates are based on an assumed albedo of 0.14 (except 163693 Atira, for which the size has been directly measured)
(B) Binary asteroid
See also
List of minor planet groups
List of minor planets
Notes
Cambridge Conference Correspondence, (2): WHAT'S IN A NAME: APOHELE = APOAPSIS & HELIOS – from Dave Tholen, Cambridge Conference Network (CCNet) DIGEST, 9 July 1998
Benny,
Duncan Steel has already brought up the subject of a class name for objects with orbits interior to the Earth's. To be sure, we've already given that subject some thought. I also wanted a word that begins with the letter "A", but there was some desire to work Hawaiian culture into it. I consulted with a friend of mine that has a master's degree in the Hawaiian language, and she recommended "Apohele", the Hawaiian word for "orbit". I found that an interesting suggestion, because of the similarity to fragments of "apoapsis" and "helios", and these objects would have their apoapsis closer to the Sun than the Earth's orbit. By the way, the pronunciation would be like "ah-poe-hey-lay". Rob Whiteley has suggested "Aliʻi", which refers to the Hawaiian elite, which provides a rich bank of names for discoveries in this class, such as Kuhio, Kalakaua, Kamehameha, Liliuokalani, and so on. Unfortunately, I think the okina (the reverse apostrophe) would be badly treated by most people.
I wasn't planning to bring it up at this stage, but because Duncan has already done so, here's what we've got on the table so far. I'd appreciate some feedback on the suggestions.
--Dave
Namely, they have coupled oscillations in orbital eccentricity and inclination
The nickname "Vatira" combined "Venus" with "Atira"[14]
References
Baalke, Ron. "Near-Earth Object Groups". Jet Propulsion Laboratory. NASA. Archived from the original on 2 February 2002. Retrieved 11 November 2016.
Chodas, Paul; Khudikyan, Shakeh; Chamberlin, Alan (14 May 2019). "Near-Earth Asteroid Discovery Statistics". Jet Propulsion Laboratory. NASA. Retrieved 25 May 2019.
Tholen, David J.; Whiteley, Robert J. (September 1998). "Results From NEO Searches At Small Solar Elongation". American Astronomical Society. 30: 1041. Bibcode:1998DPS....30.1604T.
(Ulukau Hawaiian Electronic Library)
Michel, Patrick; Zappalà, Vincenzo; Cellino, Alberto; Tanga, Paolo (February 2000). "NOTE: Estimated Abundance of Atens and Asteroids Evolving on Orbits between Earth and Sun". Icarus. Harcourt. 143 (2): 421–424. Bibcode:2000Icar..143..421M. doi:10.1006/icar.1999.6282.
Ribeiro, Anderson O.; et al. (1 June 2016). "Dynamical study of the Atira group of asteroids". Monthly Notices of the Royal Astronomical Society. 458 (4): 4471–4476. doi:10.1093/mnras/stw642.
Ye, Quanzhi; et al. (2020). "A Twilight Search for Atiras, Vatiras, and Co-orbital Asteroids: Preliminary Results". The Astronomical Journal. IOP Publishing. 159 (2): 70. doi:10.3847/1538-3881/ab629c. S2CID 209324310.
"JPL Small-Body Database Search Engine: Q < 0.983 (AU)". JPL Solar System Dynamics. NASA. Retrieved 30 December 2017.
"Small-Body Database Query". Solar System Dynamics - Jet Propulsion Laboratory. NASA - California Institute of Technology. Retrieved 2023-02-05.
"Asteroids with aphelia between 0.983 and 1.017 AU". Retrieved 25 May 2019.
de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (11 June 2018). "Kozai--Lidov Resonant Behavior Among Atira-class Asteroids". Research Notes of the AAS. 2 (2): 46. arXiv:1806.00442. Bibcode:2018RNAAS...2...46D. doi:10.3847/2515-5172/aac9ce. S2CID 119239031.
de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (1 August 2019). "Understanding the evolution of Atira-class asteroid 2019 AQ3, a major step towards the future discovery of the Vatira population". Monthly Notices of the Royal Astronomical Society. 487 (2): 2742–2752. arXiv:1905.08695. Bibcode:2019MNRAS.487.2742D. doi:10.1093/mnras/stz1437. S2CID 160009327.
Di Carlo, Marilena; Martin, Juan Manuel Romero; Gomez, Natalia Ortiz; Vasile, Massimiliano (1 April 2017). "Optimised low-thrust mission to the Atira asteroids". Advances in Space Research. Elsevier. 59 (7): 1724–1739. doi:10.1016/j.asr.2017.01.009. S2CID 116216149. Retrieved February 9, 2023.
Greenstreet, Sarah; Ngo, Henry; Gladman, Brett (January 2012). "The orbital distribution of Near-Earth Objects inside Earth's orbit" (PDF). Icarus. Elsevier. 217 (1): 355–366. Bibcode:2012Icar..217..355G. doi:10.1016/j.icarus.2011.11.010. hdl:2429/37251. "We have provisionally named objects with 0.307 < Q < 0.718 AU Vatiras, because they are Atiras which are decoupled from Venus. Provisional because it will be abandoned once the first discovered member of this class will be named."
Bolin, Bryce T.; et al. (November 2022). "The discovery and characterization of (594913) 'Ayló'chaxnim, a kilometre sized asteroid inside the orbit of Venus". Monthly Notices of the Royal Astronomical Society: Letters. 517 (1): L49–L54. doi:10.1093/mnrasl/slac089. Retrieved 1 October 2022.
"JPL Small-Body Database Browser: 2020 AV2". Jet Propulsion Laboratory. NASA. Archived from the original on 11 January 2020. Retrieved 9 January 2020.
Lai, H.T.; Ip, W.H. (4 December 2022). "The orbital evolution of Atira asteroids". Monthly Notices of the Royal Astronomical Society. 517 (4): 5921–5929. doi:10.1093/mnras/stac2991. Retrieved February 9, 2023.
Masi, Gianluca (9 January 2020). "2020 AV2, the first intervenusian asteroid ever discovered: an image – 08 Jan. 2020". Virtual Telescope Project. Retrieved 9 January 2020.
Popescu, Marcel M.; et al. (11 August 2020). "Physical characterization of 2020 AV2, the first known asteroid orbiting inside Venus orbit". Monthly Notices of the Royal Astronomical Society. 496 (3): 3572–3581. arXiv:2006.08304. Bibcode:2020MNRAS.496.3572P. doi:10.1093/mnras/staa1728. S2CID 219687045. Retrieved 8 July 2020.
External links
List Of Aten Minor Planets, Minor Planet Center
vte
Small Solar System bodies
Minor planets
Designation Groups List Moon Meanings of names
Asteroid
Active Aten asteroid Asteroid belt Family Jupiter trojan Near-Earth Spectral types
Distant minor planet
Cis-Neptunian object
Centaur Neptune trojan Damocloid Trans-Neptunian object
Detached Kuiper belt Oort cloud Scattered disc
Comets
Extinct Great Halley-type Hyperbolic Long-period Lost Near-parabolic Periodic Sungrazing
Other
Cosmic dust Meteoroids Space debris
Categories:
Atira asteroidsLists of asteroids
This page was last edited on 30 March 2023
The group of Atira (Apohele) asteroids compared to the orbits of the terrestrial planets of the Solar System.
Mars (M)
Venus (V)
Mercury (H) Sun
Atira asteroids
Earth (E)
Atira asteroids /əˈtɪrə/ or Apohele asteroids, also known as interior-Earth objects (IEOs), are asteroids whose orbits are entirely confined within Earth's orbit;[1] that is, their orbit has an aphelion (farthest point from the Sun) smaller than Earth's perihelion (nearest point to the Sun), which is 0.983 astronomical units (AU). Atira asteroids are by far the least numerous group of near-Earth objects, compared to the more populous Aten, Apollo and Amor asteroids.[2]
History
Naming
There is no official name for the class commonly referred as Atira asteroids. The term "Apohele asteroids" was proposed by the discoverers of 1998 DK36,[3] after the Hawaiian word for orbit, from apo [ˈɐpo] 'circle' and hele [ˈhɛlɛ] 'to go'.[4] This was suggested partly because of its similarity to the words aphelion (apoapsis) and helios. Other authors adopted the designation "Inner Earth Objects" (IEOs).[5] Following the general practice to name a new class of asteroids for the first recognized member of that class, which in this case was 163693 Atira, the designation of "Atira asteroids" was largely adopted by the scientific community, including by NASA.[6][1]
Discovery and observation
Their location inside the Earth's orbit makes Atiras very difficult to observe, as from Earth's perspective they are close to the Sun and therefore 'drowned out' by the Sun's overpowering light.[7] This means that Atiras can usually only be seen during twilight.[7] The first documented twilight searches for asteroids inside Earth's orbit were performed by astronomer Robert Trumpler over the early 20th century, but he failed to find any.[7]
The first suspected Atira asteroid was 1998 DK36, which was discovered by David J. Tholen of the Mauna Kea Observatory, but the first to be confirmed as such was 163693 Atira in 2003, discovered by the Arecibo Observatory. As of February 2023, there are 28 known Atiras, two of which are named, eight of which have received a numbered designation, and six of which are potentially hazardous objects.[2][8][9] An additional 127 objects have aphelia smaller than Earth's aphelion (Q = 1.017 AU).[10]
Origins
Most Atira asteroids originated in the asteroid belt and were driven to their current locations as a result of gravitational perturbation, as well as other causes such as the Yarkovsky effect.[7]
Orbits
Atiras do not cross Earth's orbit and are not immediate impact event threats, but their orbits may be perturbed outward by a close approach to either Mercury or Venus and become Earth-crossing asteroids in the future. The dynamics of many Atira asteroids resemble the one induced by the Kozai-Lidov mechanism, which contributes to enhanced long-term orbital stability, since there is no libration of the perihelion.[11][12]
Exploration
A 2017 study published in the journal Advances in Space Research proposed a low-cost space probe be sent to study Atira asteroids, citing the difficulty in observing the group from Earth as a reason to undertake the mission.[13] The study proposed that the mission would be powered by spacecraft electric propulsion and would follow a path designed to flyby as many Atira asteroids as possible. The probe would also attempt to discover new NEO's that may pose a threat to Earth.[13]
Related asteroid groups
ꞌAylóꞌchaxnim asteroids
ꞌAylóꞌchaxnim asteroids, which had been provisionally nicknamed "Vatira" asteroids before the first was discovered,[c] are a subclass of Atiras that orbit entirely interior to the orbit of Venus, aka 0.718 AU.[15] Despite their orbits placing them at a significant distance from Earth, they are still classified as near-Earth objects.[16] Observations suggest that ꞌAylóꞌchaxnim asteroids frequently have their orbits altered into Atira asteroids and vice-versa.[17]
First formally theorised to exist by Sarah Greenstreet, Henry Ngo, and Brett Gladman in 2012,[7] the first and to date only such asteroid found is 594913 ꞌAylóꞌchaxnim,[18][19] which was discovered on 4 January 2020 by the Zwicky Transient Facility. As the archetype, it subsequently gave its name to the class.[15] It has an aphelion of only 0.656 AU, making it the asteroid with the smallest known aphelion.[8][11]
Vulcanoids
Main article: Vulcanoid
No asteroids have yet been discovered to orbit entirely inside the orbit of Mercury (q = 0.307 AU). Such hypothetical asteroids would likely be termed vulcanoids, although the term often refers to asteroids which more specifically have remained in the intra-Mercurian region over the age of the solar system.[14]
Members
The following table lists the known and suspected Atiras as of February 2022. 594913 ꞌAylóꞌchaxnim, due to its unique classification, has been highlighted in pink. The interior planets Mercury and Venus have been included for comparison as grey rows.
List of known and suspected Atiras as of February 2021 (Q < 0.983 AU)[8] Designation Perihelion
(AU) Semi-major axis
(AU) Aphelion
(AU) Eccentricity Inclination
(°) Period
(days) Observation arc
(days) (H) Diameter(A)
(m) Discoverer Ref
Mercury
(for comparison) 0.307 0.3871 0.467 0.2056 7.01 88 NA -0.6 4,879,400 NA
Venus
(for comparison) 0.718 0.7233 0.728 0.0068 3.39 225 NA -4.5 12,103,600 NA
1998 DK36 0.404 0.6923 0.980 0.4160 2.02 210 1 25.0 35 David J. Tholen MPC · JPL
163693 Atira 0.502 0.7410 0.980 0.3222 25.62 233 6601 16.3 4800±500(B) LINEAR List
MPC · JPL
(164294) 2004 XZ130 0.337 0.6176 0.898 0.4546 2.95 177 3564 20.4 300 David J. Tholen List
MPC · JPL
(434326) 2004 JG6 0.298 0.6353 0.973 0.5311 18.94 185 6227 18.5 710 LONEOS List
MPC · JPL
(413563) 2005 TG45 0.428 0.6814 0.935 0.3722 23.33 205 5814 17.6 1,100 Catalina Sky Survey List
MPC · JPL
2013 JX28
(aka 2006 KZ39) 0.262 0.6008 0.940 0.5641 10.76 170 5110 20.1 340 Mount Lemmon Survey
Pan-STARRS MPC · JPL
(613676) 2006 WE4 0.641 0.7848 0.928 0.1829 24.77 254 4995 18.9 590 Mount Lemmon Survey List
MPC · JPL
(418265) 2008 EA32 0.428 0.6159 0.804 0.3050 28.26 177 4794 16.5 1,800 Catalina Sky Survey List
MPC · JPL
(481817) 2008 UL90 0.431 0.6951 0.959 0.3798 24.31 212 4496 18.6 680 Mount Lemmon Survey List
MPC · JPL
2010 XB11 0.288 0.6180 0.948 0.5339 29.89 177 1811 19.9 370 Mount Lemmon Survey MPC · JPL
2012 VE46 0.455 0.7131 0.971 0.3613 6.67 220 2225 20.2 320 Pan-STARRS MPC · JPL
2013 TQ5 0.653 0.7737 0.894 0.1557 16.40 249 2269 19.8 390 Mount Lemmon Survey MPC · JPL
2014 FO47 0.548 0.7522 0.956 0.2712 19.20 238 2779 20.3 310 Mount Lemmon Survey MPC · JPL
2015 DR215 0.352 0.6665 0.981 0.4716 4.08 199 2156 20.4 300 Pan-STARRS MPC · JPL
2017 XA1 0.646 0.8095 0.973 0.2017 17.18 266 1084 21.3 200 Pan-STARRS MPC · JPL
2017 YH
(aka 2016 XJ24) 0.328 0.6343 0.940 0.4825 19.85 185 1127 18.4 740 Spacewatch
ATLAS MPC · JPL
2018 JB3 0.485 0.6832 0.882 0.2904 40.39 206 2037 17.7 1,020 Catalina Sky Survey MPC · JPL
2019 AQ3 0.404 0.5887 0.774 0.3143 47.22 165 2175 17.5 1,120 Zwicky Transient Facility MPC · JPL
2019 LF6 0.317 0.5554 0.794 0.4293 29.51 151 796 17.3 1,230 Zwicky Transient Facility MPC · JPL
594913 ꞌAylóꞌchaxnim 0.457 0.5554 0.654 0.1770 15.87 151 609 16.2 1500+1100
−600 Zwicky Transient Facility MPC · JPL
2020 HA10 0.692 0.8196 0.947 0.1552 49.65 271 3248 18.9 590 Mount Lemmon Survey MPC · JPL
2020 OV1 0.476 0.6376 0.800 0.2541 32.58 186 1169 18.9 590 Zwicky Transient Facility MPC · JPL
2021 BS1 0.396 0.5984 0.800 0.3377 31.73 169 46 18.5 710 Zwicky Transient Facility MPC · JPL
2021 LJ4 0.416 0.6748 0.933 0.3834 9.83 202 5 20.1 340 Scott S. Sheppard MPC · JPL
2021 PB2 0.610 0.7174 0.825 0.1501 24.83 222 3392 18.8 620 Zwicky Transient Facility MPC · JPL
2021 PH27 0.133 0.4617 0.790 0.7117 31.93 115 1515 17.7 1,020 Scott S. Sheppard MPC · JPL
2021 VR3 0.313 0.5339 0.755 0.4138 18.06 143 1012 18.0 890 Zwicky Transient Facility MPC · JPL
2022 BJ8 0.590 0.7852 0.981 0.2487 15.83 254 102 19.6 430 Kitt Peak-Bok MPC · JPL
2023 EL 0.579 0.7676 0.956 0.2453 13.63 246 9 18.9 580 Scott S. Sheppard MPC · JPL
2023 EY2 0.398 0.6033 0.809 0.3978 35.55 171 6 19.9 370 Kitt Peak-Bok MPC · JPL
(A) All diameter estimates are based on an assumed albedo of 0.14 (except 163693 Atira, for which the size has been directly measured)
(B) Binary asteroid
See also
List of minor planet groups
List of minor planets
Notes
Cambridge Conference Correspondence, (2): WHAT'S IN A NAME: APOHELE = APOAPSIS & HELIOS – from Dave Tholen, Cambridge Conference Network (CCNet) DIGEST, 9 July 1998
Benny,
Duncan Steel has already brought up the subject of a class name for objects with orbits interior to the Earth's. To be sure, we've already given that subject some thought. I also wanted a word that begins with the letter "A", but there was some desire to work Hawaiian culture into it. I consulted with a friend of mine that has a master's degree in the Hawaiian language, and she recommended "Apohele", the Hawaiian word for "orbit". I found that an interesting suggestion, because of the similarity to fragments of "apoapsis" and "helios", and these objects would have their apoapsis closer to the Sun than the Earth's orbit. By the way, the pronunciation would be like "ah-poe-hey-lay". Rob Whiteley has suggested "Aliʻi", which refers to the Hawaiian elite, which provides a rich bank of names for discoveries in this class, such as Kuhio, Kalakaua, Kamehameha, Liliuokalani, and so on. Unfortunately, I think the okina (the reverse apostrophe) would be badly treated by most people.
I wasn't planning to bring it up at this stage, but because Duncan has already done so, here's what we've got on the table so far. I'd appreciate some feedback on the suggestions.
--Dave
Namely, they have coupled oscillations in orbital eccentricity and inclination
The nickname "Vatira" combined "Venus" with "Atira"[14]
References
Baalke, Ron. "Near-Earth Object Groups". Jet Propulsion Laboratory. NASA. Archived from the original on 2 February 2002. Retrieved 11 November 2016.
Chodas, Paul; Khudikyan, Shakeh; Chamberlin, Alan (14 May 2019). "Near-Earth Asteroid Discovery Statistics". Jet Propulsion Laboratory. NASA. Retrieved 25 May 2019.
Tholen, David J.; Whiteley, Robert J. (September 1998). "Results From NEO Searches At Small Solar Elongation". American Astronomical Society. 30: 1041. Bibcode:1998DPS....30.1604T.
(Ulukau Hawaiian Electronic Library)
Michel, Patrick; Zappalà, Vincenzo; Cellino, Alberto; Tanga, Paolo (February 2000). "NOTE: Estimated Abundance of Atens and Asteroids Evolving on Orbits between Earth and Sun". Icarus. Harcourt. 143 (2): 421–424. Bibcode:2000Icar..143..421M. doi:10.1006/icar.1999.6282.
Ribeiro, Anderson O.; et al. (1 June 2016). "Dynamical study of the Atira group of asteroids". Monthly Notices of the Royal Astronomical Society. 458 (4): 4471–4476. doi:10.1093/mnras/stw642.
Ye, Quanzhi; et al. (2020). "A Twilight Search for Atiras, Vatiras, and Co-orbital Asteroids: Preliminary Results". The Astronomical Journal. IOP Publishing. 159 (2): 70. doi:10.3847/1538-3881/ab629c. S2CID 209324310.
"JPL Small-Body Database Search Engine: Q < 0.983 (AU)". JPL Solar System Dynamics. NASA. Retrieved 30 December 2017.
"Small-Body Database Query". Solar System Dynamics - Jet Propulsion Laboratory. NASA - California Institute of Technology. Retrieved 2023-02-05.
"Asteroids with aphelia between 0.983 and 1.017 AU". Retrieved 25 May 2019.
de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (11 June 2018). "Kozai--Lidov Resonant Behavior Among Atira-class Asteroids". Research Notes of the AAS. 2 (2): 46. arXiv:1806.00442. Bibcode:2018RNAAS...2...46D. doi:10.3847/2515-5172/aac9ce. S2CID 119239031.
de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (1 August 2019). "Understanding the evolution of Atira-class asteroid 2019 AQ3, a major step towards the future discovery of the Vatira population". Monthly Notices of the Royal Astronomical Society. 487 (2): 2742–2752. arXiv:1905.08695. Bibcode:2019MNRAS.487.2742D. doi:10.1093/mnras/stz1437. S2CID 160009327.
Di Carlo, Marilena; Martin, Juan Manuel Romero; Gomez, Natalia Ortiz; Vasile, Massimiliano (1 April 2017). "Optimised low-thrust mission to the Atira asteroids". Advances in Space Research. Elsevier. 59 (7): 1724–1739. doi:10.1016/j.asr.2017.01.009. S2CID 116216149. Retrieved February 9, 2023.
Greenstreet, Sarah; Ngo, Henry; Gladman, Brett (January 2012). "The orbital distribution of Near-Earth Objects inside Earth's orbit" (PDF). Icarus. Elsevier. 217 (1): 355–366. Bibcode:2012Icar..217..355G. doi:10.1016/j.icarus.2011.11.010. hdl:2429/37251. "We have provisionally named objects with 0.307 < Q < 0.718 AU Vatiras, because they are Atiras which are decoupled from Venus. Provisional because it will be abandoned once the first discovered member of this class will be named."
Bolin, Bryce T.; et al. (November 2022). "The discovery and characterization of (594913) 'Ayló'chaxnim, a kilometre sized asteroid inside the orbit of Venus". Monthly Notices of the Royal Astronomical Society: Letters. 517 (1): L49–L54. doi:10.1093/mnrasl/slac089. Retrieved 1 October 2022.
"JPL Small-Body Database Browser: 2020 AV2". Jet Propulsion Laboratory. NASA. Archived from the original on 11 January 2020. Retrieved 9 January 2020.
Lai, H.T.; Ip, W.H. (4 December 2022). "The orbital evolution of Atira asteroids". Monthly Notices of the Royal Astronomical Society. 517 (4): 5921–5929. doi:10.1093/mnras/stac2991. Retrieved February 9, 2023.
Masi, Gianluca (9 January 2020). "2020 AV2, the first intervenusian asteroid ever discovered: an image – 08 Jan. 2020". Virtual Telescope Project. Retrieved 9 January 2020.
Popescu, Marcel M.; et al. (11 August 2020). "Physical characterization of 2020 AV2, the first known asteroid orbiting inside Venus orbit". Monthly Notices of the Royal Astronomical Society. 496 (3): 3572–3581. arXiv:2006.08304. Bibcode:2020MNRAS.496.3572P. doi:10.1093/mnras/staa1728. S2CID 219687045. Retrieved 8 July 2020.
External links
List Of Aten Minor Planets, Minor Planet Center
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This page was last edited on 30 March 2023
