Precovery

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The Jupiter moon Valetudo was first discovered in 2017, but a number of precovery images have been identified since, including this one taken on 28 February 2003 by the Canada-France-Hawaii Telescope, in which Valetudo's position is marked by the two orange bars. Valetudo CFHT precovery 2003-02-28 annotated.gif
The Jupiter moon Valetudo was first discovered in 2017, but a number of precovery images have been identified since, including this one taken on 28 February 2003 by the Canada–France–Hawaii Telescope, in which Valetudo's position is marked by the two orange bars.

In astronomy, precovery (short for pre-discovery recovery) [1] [2] is the process of finding the image of an object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This happens most often with minor planets, but sometimes a comet, a dwarf planet, a natural satellite, or a star is found in old archived images; even exoplanet precovery observations have been obtained. [3] "Precovery" refers to a pre-discovery image; "recovery" refers to imaging of a body which was lost to our view (as behind the Sun), but is now visible again (also see lost minor planet and lost comet).

Contents

Orbit determination requires measuring an object's position on multiple occasions. The longer the interval between observations, the more accurately the orbit can be calculated; however, for a newly discovered object, only a few days' or weeks' worth of measured positions may be available, sufficient only for a preliminary (imprecise) orbit calculation.

When an object is of particular interest (such as asteroids with a chance of impacting Earth), researchers begin a search for precovery images. Using the preliminary orbit calculation to predict where the object might appear on old archival images, those images (sometimes decades old) are searched to see if it had in fact already been photographed. If so, a far longer observation arc can allow a far more precise orbital calculation.

Until fast computers were widely available, it was impractical to analyze and measure images for possible minor planet discoveries because this required much human labor. Usually, such images were made years or decades earlier for other purposes (studies of galaxies, etc.), and it was not worth the time it took to look for precovery images of ordinary asteroids. Today, computers can easily analyze digital astronomical images and compare them to star catalogs containing up to a billion or so star positions to see if one of the "stars" is actually a precovery image of the newly discovered object. This technique has been used since the mid-1990s to determine the orbits of many minor planets.

Examples

In an extreme case of precovery, an object was discovered on December 31, 2000, designated 2000 YK66 , and a near-Earth orbit was calculated. Precovery revealed that it had previously been discovered on February 23, 1950 and given the provisional designation 1950 DA, and then been lost for half a century. The exceptionally long observation period allowed an unusually precise orbit calculation, and the asteroid was determined to have a small chance of colliding with the Earth. After an asteroid's orbit is calculated with sufficient precision, it can be assigned a number prefix (in this case, (29075) 1950 DA).

The asteroid 69230 Hermes was found in 2003 and numbered, but was found to be a discovery from 1937 which had been named "Hermes", but subsequently lost; its old name was reinstated. Centaur 2060 Chiron was discovered in 1977, and precovery images from 1895 have been located. [4]

Another noteworthy case of precovery concerns Neptune. Galileo observed Neptune on both December 28, 1612 and January 27, 1613, when it was in a portion of its orbit where it was nearly directly behind Jupiter as seen from Earth. Because Neptune moves very slowly and is very faint relative to the known planets of that time, Galileo mistook it for a fixed star, leaving the planet undiscovered until 1846. He did note that the "star" Neptune did seem to move, noting that between his two observations its apparent distance from another star had changed. However, unlike photographic images, drawings such as those Galileo made are usually not precise enough to be of use in refining an object's orbit. In 1795, Lalande also mistook Neptune for a star. [5] In 1690, John Flamsteed did the same with Uranus, even cataloging it as "34 Tauri".

One of the most exceptional suggested instances is related to the discovery of Ganymede. This again involved Galileo, who is usually stated to have discovered it in 1610. It has been postulated by Xi Zezong that Ganymede was discovered by the Chinese astronomer Gan De in 365 B.C., when he catalogued it as a small red star next to Jupiter during naked eye observation. [6]

Dwarf planets

Discovery and precovery dates for well-known dwarf planets, minor planets and probable dwarf planets:

IndexObjectDiscovery
Year		Precovery
Year		Years Elapsed Absolute
Magnitude
2 Pallas 18021779 [7] 234.13
134340 Pluto 19301909 [8] 21-0.7
19521 Chaos 19981991 [9] 75.0
20000 Varuna 20001954 [10] 463.76
38628 Huya 20001996 [11] 45.04
78799 2002 XW93 20021989 [12] 135.5
28978 Ixion 20011982 [13] 193.6
55637 2002 UX25 20021991 [14] 113.87
50000 Quaoar 20021954 [15] 482.82
307261 2002 MS4 20021954 [16] 483.7
55565 2002 AW197 20021997 [17] 53.5
2002 XV93 20021990 [18] 125.42
174567 Varda 20031980 [19] 233.1
84922 2003 VS2 20031991 [20] 124.1
208996 2003 AZ84 20031996 [21] 73.54
455502 2003 UZ413 20031954 [22] 494.38
90377 Sedna 20031990 [23] 131.83
444030 2004 NT33 20041982 [24] 224.4
230965 2004 XA192 20041989 [25] 154.1
90568 2004 GV9 20041954 [26] 504.25
90482 Orcus 20041951 [27] 532.2
175113 2004 PF115 20041992 [28] 124.54
120347 Salacia 20041982 [29] 224.36
120348 2004 TY364 20041983 [30] 214.52
136108 Haumea 20041955 [31] 490.2
145451 2005 RM43 20051976 [32] 294.4
145452 2005 RN43 20051954 [33] 513.89
202421 2005 UQ513 20051990 [34] 153.4
136199 Eris 20051954 [35] 51-1.17
136472 Makemake 20051955 [36] 50-0.3
470308 2007 JH43 20071984 [37] 234.49
229762 Gǃkúnǁʼhòmdímà 20071982 [38] 253.69
225088 Gonggong 20071985 [39] 221.8
523671 2013 FZ27 20132001 [40] 124.1
472271 2014 UM33 20142003 [41] 115.2
523794 2015 RR245 20152004 [42] 113.6
2018 VG18 20182003 [43] 153.5

Oort cloud comets

Oort cloud comets can take 10+ years going from Neptune's orbit at 30.1  AU (4.50  billion   km ) to perihelion (closest approach to the Sun). As modern survey archives reach fainter magnitudes and are more comprehensive, significant precovery images have become easier to locate.

Oort Cloud Comets
CometDiscovery
date		Precovery
date		Discovery
distance
from Sun (AU)		Precovery
distance
from Sun (AU)		Ref
C/2010 U3 (Boattini) 2010-10-312005-11-0518.425.8 JPL
C/2012 S1 (ISON) 2012-09-212011-09-306.39.4 JPL
C/2013 A1 (Siding Spring) 2013-01-032012-10-047.27.9 JPL
C/2017 K2 (PANSTARRS) 2017-05-212013-05-1216.123.7 JPL

See also

Related Research Articles

474640 Alicanto (provisional designation 2004 VN112) is a detached extreme trans-Neptunian object. It was discovered on 6 November 2004, by American astronomer Andrew C. Becker at Cerro Tololo Inter-American Observatory in Chile. It never gets closer than 47 AU from the Sun (near the outer edge of the main Kuiper belt) and averages more than 300 AU from the Sun. Its large eccentricity strongly suggests that it was gravitationally scattered onto its current orbit. Because it is, like all detached objects, outside the current gravitational influence of Neptune, how it came to have this orbit cannot yet be explained. It was named after Alicanto, a nocturnal bird in Chilean mythology.

<span class="mw-page-title-main">Lost minor planet</span> Asteroids whose orbits are not known accurately enough to find them again

A minor planet is "lost" when today's observers cannot find it, because its location is too uncertain to target observations. This happens if the orbital elements of a minor planet are not known accurately enough, typically because the observation arc for the object is too short, or too few observations were made before the object became unobservable.

(470308) 2007 JH43 (provisional designation 2007 JH43) is a trans-Neptunian object in the outer regions of the Solar System, approximately 500 kilometers in diameter. It was discovered on 10 May 2007, by the U.S. Palomar Observatory in California. The team of unaccredited astronomers at Palomar consisted of Megan E. Schwamb, Michael E. Brown and David L. Rabinowitz

<span class="nowrap">(528381) 2008 ST<sub>291</sub></span>

(528381) 2008 ST291, provisional designation 2008 ST291, is a 1:6 resonant trans-Neptunian object located in the outermost region of the Solar System that takes almost a thousand years to complete an orbit around the Sun. It was discovered on 24 September 2008 by American astronomers Megan Schwamb, Michael Brown and David Rabinowitz at the Palomar Observatory in California, with no known earlier precovery images.

<span class="mw-page-title-main">471143 Dziewanna</span> Scattered disc object

471143 Dziewanna (provisional designation 2010 EK139) is a trans-Neptunian object in the scattered disc, orbiting the Sun in the outermost region of the Solar System.

<span class="nowrap">(612533) 2002 XV<sub>93</sub></span>

(612533) 2002 XV93 (provisional designation 2002 XV93) is a trans-Neptunian object (TNO) with an absolute magnitude of 5.4. A 2:3 orbital resonance with Neptune makes it a plutino.

(444030) 2004 NT33 is a classical trans-Neptunian object and possible dwarf planet of the Kuiper belt in the outermost region of the Solar System, approximately 450 kilometers in diameter. It was discovered on 13 July 2004, by astronomers at Palomar Observatory, California, United States.

(523639) 2010 RE64 (provisional designation 2010 RE64) is a trans-Neptunian object in the scattered disc located in the outermost region of the Solar System, approximately 570 kilometers (350 miles) in diameter. It was discovered on 11 July 2010 by the Pan-STARRS-1 survey at the Haleakala Observatory, Hawaii, in the United States.

2004 BX159, is an asteroid from the central region of the asteroid belt, approximately 1.2 kilometers in diameter. It was first observed at Paranal Observatory in the Atacama desert of Chile on 20 January 2004. 2004 BX159 missed the virtual impactor date of 29 August 2009. The asteroid was removed from the Sentry Risk Table in April 2014 as a result of precovery images establishing it is a harmless main belt asteroid.

(589683) 2010 RF43 (provisional designation 2010 RF43) is a large trans-Neptunian object orbiting in the scattered disc in the outermost regions of the Solar System. The object was discovered on 9 September 2010, by American astronomers David Rabinowitz, Megan Schwamb and Suzanne Tourtellotte at ESO's La Silla Observatory in northern Chile.

(445473) 2010 VZ98 (provisional designation 2010 VZ98) is a trans-Neptunian object of the scattered disc, orbiting the Sun in the outermost region of the Solar System. It has a diameter of approximately 400 kilometers.

(523643) 2010 TY53, provisional designation 2010 TY53 is a trans-Neptunian object and possible centaur located in the outermost region of the Solar System. With an absolute magnitude of 5.7, it approximately measures 325 kilometers (200 miles) in diameter. It was discovered on 4 August 2010 by the Pan-STARRS-1 survey at the Haleakala Observatory, Hawaii, in the United States. According to American astronomer Michael Brown, it is "possibly" a dwarf planet.

(471288) 2011 GM27 (provisional designation 2011 GM27) is a trans-Neptunian object (TNO) in the Kuiper belt, classified as a hot classical Kuiper belt object. It was discovered on 2 April 2011, at ESO's La Silla Observatory in Chile. With an absolute magnitude of 5.32, a geometric albedo of between 0.06 to 0.09 (a typical value) would mean it has a diameter of about 450 kilometers (280 mi).

(472271) 2014 UM33 (provisional designation 2014 UM33) is a trans-Neptunian object residing in the outer Kuiper belt. It was discovered on October 22, 2014, by the Mount Lemmon Survey.

(574372) 2010 JO179 (provisional designation 2010 JO179) is a large, high-order resonant trans-Neptunian object in the outermost regions of the Solar System, approximately 700 kilometers (430 miles) in diameter. Long-term observations suggest that the object is in a meta-stable 5:21 resonance with Neptune. Other sources classify it as a scattered disc object. It is possibly large enough to be a dwarf planet.

(495603) 2015 AM281 (provisional designation 2015 AM281) is a resonant trans-Neptunian object in the outermost region of the Solar System, guesstimated at approximately 470 kilometers (290 miles) in diameter. It was discovered on 13 March 2010, by astronomers with the Pan-STARRS survey at Haleakala Observatory, Hawaii, United States.

2021 DR15 is a large trans-Neptunian object in the scattered disc, around 700 kilometres (430 miles) in diameter. It was discovered on 17 February 2021, by American astronomers Scott Sheppard, David Tholen, and Chad Trujillo using the 8.2-meter Subaru Telescope of the Mauna Kea Observatories in Hawaii, and announced on 17 December 2021. It was 89.4 astronomical units from the Sun when it was discovered, making it the ninth-most distant known Solar System object from the Sun as of December 2021. It has been identified in several precovery images as far back as 10 March 2005.

2021 LL37 is a large trans-Neptunian object in the scattered disc, around 600 kilometres (370 miles) in diameter. It was discovered on 12 June 2021, by American astronomers Scott Sheppard and Chad Trujillo using Cerro Tololo Inter-American Observatory's Dark Energy Camera in Chile, and announced on 31 May 2022. It was 73.9 astronomical units from the Sun when it was discovered, making it one of the most distant known Solar System objects from the Sun as of May 2022. It has been identified in precovery images from as far back as 28 April 2014.

2021 RR205 is an extreme trans-Neptunian object discovered by astronomers Scott Sheppard, David Tholen, and Chad Trujillo with the Subaru Telescope at Mauna Kea Observatory on 5 September 2021. It resides beyond the outer extent of the Kuiper belt on a distant and highly eccentric orbit detached from Neptune's gravitational influence, with a large perihelion distance of 55.5 astronomical units (AU). Its large orbital semi-major axis (~1,000 AU) suggests it is potentially from the inner Oort cloud. 2021 RR205 and 2013 SY99 both lie in the 50–75 AU perihelion gap that separates the detached objects from the more distant sednoids; dynamical studies indicate that such objects in the inner edge this gap weakly experience "diffusion", or inward orbital migration due to minuscule perturbations by Neptune. While Sheppard considers 2021 RR205 a sednoid, researchers Yukun Huang and Brett Gladman do not.

References

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  2. ↑ D.I. Steel, R.H. McNaught, G.J. Garradd, D.J. Asher and K.S. Russell (25 March 1997). "AANEAS: A Valedictory Report". Archived from the original on 2012-07-28.{{cite web}}: CS1 maint: multiple names: authors list (link)
  3. ↑ Villard, Ray; Lafreniere, David (April 1, 2009). "Hubble Finds Hidden Exoplanet in Archival Data". HubbleSite NewsCenter. NASA. Archived from the original on April 5, 2009. Retrieved 2024-06-25.
  4. ↑ "JPL Small-Body Database Browser: 2060 Chiron (1977 UB)" (2009-09-17 last obs). Archived from the original on 2011-06-09. Retrieved 2010-02-08.
  5. ↑ Fred William Price (2000). The planet observer's handbook . Cambridge University Press. p.  352. ISBN   9780521789813 . Retrieved 2009-09-11.
  6. ↑ "Galilean Moons– Gan De". Archived from the original on 2017-12-01. Retrieved 27 November 2017.
  7. ↑ "Charles Messier, premier observateur de l'astéroïde Pallas". cieletespace.fr. Archived from the original on 16 March 2016. Retrieved 7 May 2018.
  8. ↑ Wild, W. J.; Buchwald, G.; Dimario, M. J.; Standish, E. M. (December 1998). "Serendipitous Discovery of the Oldest Known Photographic Plates with Images of Pluto". American Astronomical Society. 30: 1449. Bibcode:1998DPS....30.5514W.
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  10. ↑ Chamberlin, Alan. "JPL Small-Body Database Browser". ssd.jpl.nasa.gov. Archived from the original on 7 May 2018. Retrieved 7 May 2018.
  11. ↑ "JPL Small-Body Database Browser: 38628 Huya (2000 EB173)" (2009-06-13 last obs). Archived from the original on 2018-05-07. Retrieved 2010-02-09.
  12. ↑ "JPL Small-Body Database Browser".
  13. ↑ "JPL Small-Body Database Browser: 28978 Ixion (2001 KX76)" (2009-05-21 last obs). Archived from the original on 2015-11-05. Retrieved 2010-02-08.
  14. ↑ "JPL Small-Body Database Browser".
  15. ↑ "JPL Small-Body Database Browser: 50000 Quaoar (2002 LM60)" (2009-09-12 last obs). Archived from the original on 2011-06-11. Retrieved 2010-02-08.
  16. ↑ "JPL Small-Body Database Browser: (2002 MS4)". 2011-12-12. Archived from the original on 2012-04-15. Retrieved 2015-01-28.
  17. ↑ "JPL Small-Body Database Browser".
  18. ↑ "JPL Small-Body Database Browser".
  19. ↑ "JPL Small-Body Database Browser".
  20. ↑ "JPL Small-Body Database Browser".
  21. ↑ "JPL Small-Body Database Browser".
  22. ↑ "JPL Small-Body Database Browser".
  23. ↑ "JPL Small-Body Database Browser: 90377 Sedna (2003 VB12)" (2010-01-05 last obs). Archived from the original on 2016-03-25. Retrieved 2010-02-08.
  24. ↑ "JPL Small-Body Database Browser".
  25. ↑ "JPL Small-Body Database Browser".
  26. ↑ "JPL Small-Body Database Browser".
  27. ↑ "JPL Small-Body Database Browser: 90482 Orcus (2004 DW)" (2009-04-28 last obs). Archived from the original on 2015-11-05. Retrieved 2010-02-08.
  28. ↑ "JPL Small-Body Database Browser".
  29. ↑ "JPL Small-Body Database Browser".
  30. ↑ "JPL Small-Body Database Browser".
  31. ↑ "JPL Small-Body Database Browser: 136108 Haumea (2003 EL61)" (2010-01-26 last obs). Archived from the original on 2011-06-09. Retrieved 2010-02-08.
  32. ↑ "JPL Small-Body Database Browser".
  33. ↑ "JPL Small-Body Database Browser".
  34. ↑ "JPL Small-Body Database Browser".
  35. ↑ "JPL Small-Body Database Browser: 136199 Eris (2003 UB313)" (2009-11-20 last obs). Archived from the original on 2011-05-12. Retrieved 2010-02-08.
  36. ↑ "JPL Small-Body Database Browser: 136472 Makemake (2005 FY9)" (2010-01-26 last obs). Archived from the original on 2011-08-30. Retrieved 2010-02-08.
  37. ↑ "JPL Small-Body Database Browser".
  38. ↑ "JPL Small-Body Database Browser".
  39. ↑ "JPL Small-Body Database Browser: 225088 (2007 OR10)" (2009-10-19 last obs). Archived from the original on 2011-11-15. Retrieved 2010-02-08.
  40. ↑ "JPL Small-Body Database Browser: 2013 FZ27)" (2014-03-26 last obs). Retrieved 2015-04-13.
  41. ↑ "JPL Small-Body Database Browser".
  42. ↑ "JPL Small-Body Database Browser: 2015 RR245)" (2016-06-08 last obs). Archived from the original on 2016-12-27. Retrieved 2016-12-26.
  43. ↑ "JPL Small-Body Database Browser".
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