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2022 AP7
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| Discovery[1] | |
|---|---|
| Discovered by | S. S. Sheppard |
| Discovery site | Cerro Tololo Observatory |
| Discovery date | 13 January 2022 |
| Designations | |
| 2022 AP7 | |
| NEO · Apollo · PHA[2] | |
| Orbital characteristics[3] | |
| Epoch 9 August 2022 (JD 2459800.5) | |
| Uncertainty parameter 1 | |
| Observation arc | 4.86 yr (1,774 days) |
| Earliest precovery date | 20 December 2017 |
| Aphelion | 5.015 AU |
| Perihelion | 0.833 AU |
| 2.924 AU | |
| Eccentricity | 0.7151 |
| 5.00 yr[3] | |
| 25.857° | |
| 0° 11m 49.647s / day | |
| Inclination | 13.835° |
| 192.377° | |
| 30 March 2022 | |
| 113.590° | |
| Earth MOID | 0.04716 AU (7,055,000 km; 18.35 LD) |
| Mars MOID | 0.07344 AU (10,986,000 km; 28.58 LD)[2] |
| Jupiter MOID | 1.19258 AU (178.407 Gm) |
| Physical characteristics | |
| 1.1–2.3 km[4][a] 1.2 km[5][b] | |
| 17.1±0.2[4][3] 17.3 (MPC)[2] | |
2022 AP7 is a kilometer-sized Apollo asteroid and potentially hazardous object orbiting between Venus and Jupiter. It was discovered on 13 January 2022 by Scott Sheppard at Cerro Tololo Observatory.[1] Based on its absolute magnitude (H), 2022 AP7 is likely the largest potentially hazardous object identified in the eight years prior to its 2022 discovery.[4][c]
Discovery
[edit]2022 AP7 was discovered as part of Sheppard's twilight survey for near-Earth asteroids interior to Earth and Venus, using Cerro Tololo Observatory's Dark Energy Camera.[1] Notable discoveries from this survey include the Atira asteroids 2021 LJ4 and 2021 PH27, the latter of which holds the record for the shortest orbital period of any known asteroid as of 2022[update].[4]
Orbit and classification
[edit]2022 AP7 is considered "potentially hazardous" only because of its large size and low Earth minimum orbit intersection distance (MOID) just within 0.05 AU (7.5 million km; 19 LD).[3][4] However, the asteroid does not currently make notable close approaches to Earth because it is in a 1:5 near orbital resonance with Earth,[8] which means it nearly takes exactly 5.0 years to orbit the Sun in a highly elliptical orbit.[3] This resonance regularly puts it in positions where observational conditions are unfavorable; the asteroid is obscured by the Sun's glare when it becomes brightest near perihelion at low solar elongations and can be fainter at opposition when it is farther from Earth.[4] As a result, 2022 AP7 could only be efficiently searched at twilight when at its brightest; the asteroid was 45 degrees from the Sun and 1.9 AU from Earth when it was discovered.[4][9] The asteroid made its closest approach 1.47 AU from Earth on 7 March 2022.[10] The asteroid will not come this close to Earth again until March 2027.[11] By May 2022, when the asteroid was 1 AU from the Sun and near the ecliptic, Earth was on the other side of the Sun, 1.9 AU from the asteroid.[12]
The asteroid is not risk listed. 2022 AP7's orbit is well-determined and will guarantee only distant approaches beyond 1.1 AU (160 million km; 430 LD) of Jupiter over the next 146 years.[3][8] The asteroid will also pass 0.16 AU (24 million km; 62 LD) from Mars on 9 May 2107.[13] Nominally the asteroid will not approach 1 AU from Earth until April 2332.[14] Over the next several centuries if not thousands of years, repeated perturbations by these encounters will eventually break the 1:5 near orbital resonance of 2022 AP7, potentially leading to an impact with Earth.[15]
| Object | Date | Nearest approach (AU) |
|---|---|---|
| Mars | 2107-05-09 | 0.16 AU (24 million km; 62 LD)[13] |
| Venus | 2147-04-22 | 0.23 AU (34 million km; 90 LD)[16] |
| Mercury | 2062-03-07 | 0.44 AU (66 million km; 170 LD)[17] |
| Sun | 2057-03-26 | 0.82 AU (123 million km; 320 LD)[18] |
| Jupiter | 2109-09-30 | 1.19 AU (178 million km; 460 LD)[3] |
| Earth | 2052-03-12 | 1.37 AU (205 million km; 530 LD)[19] |
Notes
[edit]- ^ Diameter range based on absolute magnitude of 17.1 and assumed albedo range of 0.20 to 0.05.
- ^ An absolute magnitude of 17.3 and assumed albedo of 0.14 gives a diameter of 1,231 m (1.231 km) (or ≈1.2 km after rounding). PHAs brighter than absolute magnitude 17.75 are likely larger than 1 km in size.
- ^ 2014 LJ21 was discovered on 5 June 2014 and has an absolute magnitude of 16.05[6] with an estimated diameter of ≈2.2 km. Another potentially hazardous asteroid similar in size to 2022 AP7 is 2022 RX3 (absolute magnitude of 17.64)[7] estimated to be ≈1.1 km in diameter.
References
[edit]- ^ a b c "MPEC 2022-B21 : 2022 AP7". IAU Minor Planet Center. 23 January 2022. Retrieved 1 November 2022.
- ^ a b c 2022 AP7 at Minor Planet Center, retrieved 31 October 2022
- ^ a b c d e f g "JPL Small-Body Database Browser: (2022 AP7)". Jet Propulsion Laboratory. Retrieved 31 October 2021.
- ^ a b c d e f g Sheppard et al. 2022.
- ^ "ESA Summary: 2022AP7". European Space Agency. Retrieved 1 November 2022.
- ^ 2014 LJ21 at Minor Planet Center, accessed 31 October 2022
- ^ 2022 RX3 at Minor Planet Center, accessed 1 November 2022
- ^ a b USA Today 2022.
- ^ "Horizons Batch for January 2022 Range and Solar Elongation". JPL Horizons. Retrieved 1 November 2022.
- ^ "JPL/HORIZONS (2022 AP7)". JPL Horizons. Retrieved 6 October 2024.
- ^ "Horizons Batch for 2022 to 2055". JPL Horizons. Retrieved 31 October 2022. (text search: "n.a. 1.4")
- ^ "Horizons Batch for 1au at ecliptic". JPL Horizons. Retrieved 2 November 2022.
- ^ a b "Horizons Batch for Mars 2107". JPL Horizons. Archived from the original on 3 November 2022. Retrieved 2 November 2022.
- ^ "Horizons Batch for Earth 2332". JPL Horizons. Archived from the original on 4 November 2022. Retrieved 6 November 2022.
- ^ NYT 2022.
- ^ "Horizons Batch for Venus 2147". JPL Horizons. Archived from the original on 4 November 2022. Retrieved 4 November 2022.
- ^ "Horizons Batch for Mercury 2062". JPL Horizons. Archived from the original on 4 November 2022. Retrieved 4 November 2022.
- ^ "Horizons Batch for Sun 2057 (Perihelion)". JPL Horizons. Retrieved 4 November 2022.
- ^ "Horizons Batch for Earth 2052". JPL Horizons. Archived from the original on 4 November 2022. Retrieved 4 November 2022.
Sources
[edit]- Isaac Schultz (31 October 2022). "Scientists Find Potentially Hazardous Asteroid Hiding in the Sun's Glare". Gizmodo.
At nearly 1.5 kilometers wide, it's the largest such asteroid discovered in eight years.
- Robin George Andrews (31 October 2022). "'Planet Killer' Asteroid Spotted That Poses Distant Risk to Earth". The New York Times.
- Ashley Strickland (31 October 2022). "'Planet killer' asteroid spotted hiding in the sun's glare". CNN.
- Scott S. Sheppard; et al. (29 September 2022), "A Deep and Wide Twilight Survey for Asteroids Interior to Earth and Venus", The Astronomical Journal, 164 (4), American Astronomical Society: 168, arXiv:2209.06245, doi:10.3847/1538-3881/ac8cff, hdl:10261/296405
- Tereza Pultarova (31 October 2022). "'Planet killer' asteroid found hiding in sun's glare may one day hit Earth". Space.com.
- Scott Gleeson; Jordan Mendoza (1 November 2022). "'Planet killer' asteroids nearly a mile long detected after being hidden by the sun's brightness". USA Today.
'It remains very far from Earth, kind of locked in a resonance that keeps it as being actually one of the most distant of the asteroids that we categorize as potentially hazardous.' ... 2022 AP7 is only projected to have close approaches to Mars and Jupiter in the next 145 years [not Earth].
- 2022 AP7 at the JPL Small-Body Database
External links
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2022 AP7
View on Grokipediafrom Grokipedia
Discovery and Observation
Discovery Circumstances
2022 AP7 was discovered on January 13, 2022, by astronomers Scott S. Sheppard of the Carnegie Institution for Science, David J. Tholen of the University of Hawai'i, and Chadwick A. Trujillo of the Northern Arizona University, as part of an international team conducting a deep and wide twilight survey for near-Earth asteroids.[4][1] The detection occurred using the Dark Energy Camera (DECam) mounted on the Víctor M. Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory in Chile.[4][1] The survey targeted elusive asteroids in the inner Solar System, specifically those orbiting interior to Earth and Venus, where the glare of the Sun typically hinders detections even with large telescopes.[4] On the night of discovery, the asteroid was captured in three images taken at the Cerro Tololo DECam observatory, with an apparent magnitude of approximately 20.8 in the r-band, necessitating the use of a 4-meter-class telescope for reliable detection.[5] These initial observations spanned a short arc sufficient to confirm the object's motion against the stellar background.[4] The provisional designation 2022 AP7 was promptly assigned by the Minor Planet Center (MPC), the official body responsible for cataloging minor planet observations and designations.[5] This naming follows the MPC's standard convention for provisional objects, based on the year and sequential discovery order within the half-month period. The discovery highlighted the effectiveness of twilight imaging techniques in revealing previously hidden populations of near-Earth objects.[4]Follow-up Observations
Following the initial detection on January 13, 2022, using the Dark Energy Camera (DECam) mounted on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile, follow-up observations were promptly conducted to confirm 2022 AP7's existence and improve the preliminary orbit determination.[6] The asteroid was recovered on January 16, 18, 21, and 23, 2022, using DECam, as well as the 1-meter telescopes of the Las Cumbres Observatory Global Telescope Network and the 2.2-meter University of Hawaii telescope on Mauna Kea, Hawaii.[6] These efforts extended the initial observation arc from a single night to several weeks, allowing for initial confirmation of its trajectory.[6] Subsequent analysis identified pre-discovery observations in archival data from the Pan-STARRS1 survey (2017) and the Catalina Sky Survey (2017), which significantly refined the orbit by incorporating earlier positions of the asteroid.[6] This extended the observation arc to approximately 5 years, from December 20, 2017, to February 15, 2022, at the time of publication, providing a more robust dynamical model.[6] As of November 2022, the last reported observations were recorded on November 2, spanning an arc of 1778 days from the earliest precovery to the final detection, with continued monitoring by near-Earth object surveys to track any changes. As of November 2025, no additional observations have been reported. The asteroid's position in the inner solar system, often in the daytime sky close to the Sun, presented significant challenges for these observations, necessitating twilight imaging sessions limited to brief 10-minute windows each night and strict solar elongation constraints to mitigate glare and atmospheric distortion.[6][5][3]Physical Properties
Size and Mass Estimates
The estimated diameter of 2022 AP7 ranges from 0.9 to 2.0 kilometers (0.56 to 1.24 miles), based on its absolute magnitude of H = 17.3 and assumed albedos between 0.05 and 0.25.[4] This makes it one of the largest potentially hazardous asteroids discovered in the past eight years.[4] The size calculation relies on the standard relationship between an asteroid's brightness, distance, and reflectivity, where lower albedo values (darker surfaces) imply larger diameters for the same observed magnitude. The mass of 2022 AP7 has not been directly measured but can be inferred from its size estimates and typical density assumptions for stony asteroids, yielding approximately 1 to 10 billion metric tons.[4] Assuming a density of about 2.7 g/cm³—common for S-type asteroids—the volume derived from the diameter range supports this mass order of magnitude.[7] Although smaller than the Chicxulub impactor (10–15 km in diameter) that caused the dinosaur extinction, an Earth impact by 2022 AP7 could still produce global catastrophic effects, including widespread fires, tsunamis, and atmospheric disruption.[8] Uncertainties in the size and mass stem primarily from the unknown albedo, with no radar observations available yet due to the asteroid's proximity to the Sun and distance from Earth.[4]Spectral Type and Composition
The spectral type of 2022 AP7 remains unclassified, as no dedicated visible or near-infrared spectroscopic observations have been published as of November 2025.[4] The asteroid's discovery and subsequent follow-up efforts have prioritized orbital characterization over surface spectroscopy, owing to its challenging visibility near the Sun's glare during much of its orbit. Limited photometric data from ground-based telescopes, including the Dark Energy Camera on the Blanco 4 m telescope, provide the primary constraints on its physical properties, but these do not resolve absorption features diagnostic of taxonomy.[4] The assumed albedo range of 0.05 to 0.25, used with the absolute magnitude of H = 17.3 to compute diameter bounds, is consistent with both carbonaceous (C-type) and silicaceous (S-type) compositions, though S-complex asteroids dominate among Apollo near-Earth objects, comprising approximately 46% of classified samples in recent surveys.[9] S-types typically exhibit moderate albedos of 0.10–0.30 and spectral features indicative of silicates, including olivine and pyroxene, akin to ordinary chondrites.[9] The composition of 2022 AP7 is likely a predominantly rocky surface, with silicates and possible iron-nickel metal alloys, based on the prevalence of S-complex materials in dynamically similar inner solar system asteroids.[9] Low abundances of organics are anticipated due to thermal alteration from close solar approaches at perihelion (q ≈ 0.83 AU), which would drive off volatile compounds over evolutionary timescales.[4] No evidence of hydrated minerals or significant carbon-rich materials has been reported, aligning with the de-volatilized nature of objects in Earth-crossing orbits.[9]Orbital Characteristics
Orbital Elements
The orbit of 2022 AP7 is described by Keplerian orbital elements derived from astrometric observations, primarily using the JPL Horizons ephemeris system. These elements define its highly elliptical path around the Sun, with the asteroid classified as an Apollo-type near-Earth object due to its Earth-crossing trajectory. The osculating elements, based on observations up to 2022 and referenced to an epoch of JD 2460200.5 (approximately August 2023), are as follows: Key orbital elements are summarized in the following table:| Element | Value | Unit |
|---|---|---|
| Semi-major axis () | 2.923 | AU |
| Eccentricity () | 0.715 | - |
| Inclination () | 13.83 | ° |
| Argument of periapsis () | 113.58 | ° |
| Longitude of ascending node () | 192.38 | ° |
| Mean anomaly () | 104.78 | ° |
| Perihelion distance () | 0.83 | AU |
| Aphelion distance () | 5.01 | AU |