4337 Arecibo

Last updated

4337 Arecibo
Discovery [1]
Discovered by E. Bowell
Discovery site Anderson Mesa Stn.
Discovery date14 April 1985
Designations
(4337) Arecibo
Named after
 Arecibo Observatory [2]
1933 HE ·1979 FR3
1979 HG2 ·1985 GB
main-belt   [2] [1]  ·(outer)
Themis   [3]
Orbital characteristics   [1]
Epoch 9 August 2022 (JD 2459800.5)
Uncertainty parameter 0
Observation arc 88.42 yr (32,295 d)
Earliest precovery date24 April 1933
Aphelion 3.5626 AU
Perihelion 2.9702 AU
3.2664 AU
Eccentricity 0.0907
5.90 yr (2,156 d)
104.049°
0° 10m 1.041s / day
Inclination 2.2131°
41.175°
183.07°
Physical characteristics [3]
Mean diameter
24.4±0.6 km (primary) [4] : 4 
Mean density
<1.3 g/cm3 [5] : 17 
32.972823  h ( Gaia DR3) [5] : 16 
32.85±0.38 h [6] [5]
60°±3° [5] : 16 
261°±3° [5] : 16 
0.077±0.004 [7] [1]
0.06±0.02 [8]
11.9±0.1 [7]  ·12.45 [8]
12.52 [1] [2]

    4337 Arecibo (prov. designation: 1985 GB) is a binary asteroid in the outer regions of the asteroid belt, approximately 24 kilometers (15 miles) in diameter. It was discovered on 14 April 1985, by American astronomer Edward Bowell at the Anderson Mesa Station near Flagstaff, Arizona, in the United States. It was named after the Arecibo Observatory in Puerto Rico. [2] It has a relatively large minor-planet moon that was discovered in stellar occultation observations by David Gault and Peter Nosworthy in May 2021, distinguishing it as the first asteroid moon discovered and confirmed solely using the occultation method. [9]

    Contents

    History

    Discovery

    This asteroid was discovered by American astronomer Edward Bowell while measuring a pair of images taken with the Lowell Observatory's 0.33-meter astrograph on 14 April 1985, located at the Anderson Mesa Station near Flagstaff, Arizona, in the United States. [10] : 71  The discovery observations were published by the Minor Planet Center on 4 May 1985. [10] : 71  In September 1985, astronomers Kiichirō Furukawa and Lutz D. Schmadel both identified the asteroid in prediscovery observations from March and April 1979, while Furukawa independently found earlier prediscovery observations from April 1933. [11] : 59  With these prediscovery observations linked, the asteroid's orbit was significantly improved and eventually received its permanent minor planet number of 4337 from the Minor Planet Center on 11 January 1990. [12] : 90 

    Naming

    The asteroid was named after the Arecibo Observatory in Puerto Rico, home to the world's largest filled-aperature radio telescope in the 20th century. The name was proposed by radar astronomer Steven J. Ostro, in recognition of the observatory's indispensable contributions to the characterization of Solar System bodies including asteroids. [2] The official naming citation was published by the Minor Planet Center on 8 June 1990. [13] : 155 

    Occultations and satellite discovery

    On 19 May 2021, two amateur astronomers, David Gault and Peter Nosworthy, observed Arecibo passing in front of a magnitude 13.6 star and blocking out its light from New South Wales, Australia. [9] [4] : 3  Each observed the stellar occultation using high-speed video cameras attached to their 30-cm aperture telescopes at their home observatories, separated from each other by 0.7 km (0.43 mi) across (perpendicular) and 18 km (11 mi) along (parallel) the path of Arecibo's shadow across Earth. [4] : 3  They detected a two-second-long occultation starting at 17:58 UTC, but then unexpectedly detected a secondary, shorter-duration occultation three seconds later. [9] [4] : 3  The observed drop in the star's brightness for both events was much greater than would be expected for a double star with one component occulted, leading Gault and Nosworthy to the conclusion that the secondary occultation was more likely caused by a natural satellite orbiting Arecibo. [4] : 3 

    Several days after the discovery of Arecibo's satellite, other occultation astronomers were alerted to follow up in another occultation event by Arecibo over North America on 9 June 2021. [9] Richard Nolthenius and Kirk Bender, separated from each other by 8.2 km (5.1 mi) across and 8 km (5.0 mi) along Arecibo's shadow path, successfully observed the 9 June 2021 occultation from central California. [4] : 3  As Arecibo passed in front of a magnitude 12.0 star, they detected the primary two-second-long occultation starting at 10:58 UTC and then the satellite make a secondary occultation three seconds later, confirming the existence of Arecibo's satellite. [9] [4] : 4  The satellite discovery and confirmation results from the May and June 2021 occultations were formally published by Central Bureau for Astronomical Telegrams on 20 June 2021. [14] Discoverers Gault and Nosworthy recognize Arecibo's satellite as the first asteroid moon discovered by amateur astronomers, and confirmed using the occultation method. [9] [lower-alpha 1]

    On 30 June 2021, astronomers across the United States prepared for another occultation by Arecibo to further follow up on its satellite, but majority of them experienced technical difficulties and unfavorable weather conditions, resulting in only 5 out of 15 different sites making successful observations. Only 3 of the 5 successful sites reported positive detections (Nolthenius, Bender, and Christopher Kitting of CSU East Bay reported positives) with a single occultation; the other two had misses and did not detect the satellite. It is possible the satellite and main body were a blended image, given the close orbit later determined. [4] : 4 

    Orbit and classification

    Arecibo orbits the Sun in the outer main-belt at a distance of 3.0–3.6  AU once every 5 years and 11 months (2,156 days; semi-major axis of 3.27 AU). Its orbit has an eccentricity of 0.09 and an inclination of 2° with respect to the ecliptic. [1] Arecibo's orbit is similar to that of the large asteroid 24 Themis, which indicates that Arecibo belongs to the Themis family ( 602 ), a very large family of carbonaceous asteroids that are believed to have originated as fragments from an impact event on Themis. [15] : 320 

    Because of its low orbital inclination, Arecibo is visible along the ecliptic at apparent magnitudes 16–18. [2] Arecibo is too faint to be seen with the naked eye, even when at its peak brightness of magnitude 16 at opposition—a telescope of at least 60 cm (24 in) in aperture size is required to see it. [16]

    Physical characteristics

    The spectral class of Arecibo is unknown, but it can be assumed to be a carbonaceous C-type, [3] similar to most members of the Themis family. [15] : 320  Like most members of the Themis family, Arecibo likely has a highly porous internal structure with a low density below 1.3 g/cm3, as indicated by its mass determined from the satellite's orbital motion. [5] : 17 

    Diameter and albedo

    Based on occultation observations from 9 June 2021, the primary body of the Arecibo system measures 24.4 ± 0.6 km (15.16 ± 0.37 mi) in diameter, assuming that it has a spherical shape. [4] On the other hand, infrared thermal emission measurements by the Japan Aerospace Exploration Agency's Akari and NASA's Wide-field Infrared Survey Explorer (WISE) determined smaller diameters of 17.6 and 19.7 km (10.9 and 12.2 mi), respectively, with corresponding geometric albedos of 0.10 and 0.08. [3] The discrepancy between the occultation and infrared measurements may be caused by a highly flattened shape for both components of the Arecibo system; in this case the occultation-derived primary diameter would represent the maximum extent of its shape. [5] : 17  WISE's estimates for Arecibo's absolute magnitude range from 11.9 to 12.6, with an average of 12.4 assumed by the Collaborative Asteroid Lightcurve Link. [3] The Minor Planet Center and Jet Propulsion Laboratory's Small-Body Database both determine an absolute magnitude of 12.5 based on visible photometry only. [2] [1]

    Rotation

    In July 2021, a preliminary rotational lightcurve of Arecibo was obtained from photometric observations by Swiss astronomer Raoul Behrend at Geneva Observatory in Switzerland. [6] Lightcurve analysis gave an approximate rotation period of 32.85±0.38 hours with a brightness amplitude of 0.17 magnitude (U=2). [3] High-precision photometry and astrometry from the Gaia spacecraft confirmed this period and showed that it is equal to the satellite's orbital period, suggesting that the Arecibo primary is in synchronous rotation with the satellite's orbital period. [5] : 16 

    Based on Gaia photometry, Arecibo's north pole points in the direction of ecliptic longitude 271° and ecliptic latitude 68°. Gaia astrometry for the satellite's orbit yields a pole orientation of ecliptic longitude 261°±3° and ecliptic latitude 60°±3°, in agreement with the photometry-derived pole orientation. [5] : 16  This suggests the axial tilt of Arecibo primary is aligned with the satellite's orbital inclination at 30° with respect to the ecliptic. [lower-alpha 2]

    Satellite

    Discovery [14]
    Discovered by D. Gault
    P. Nosworthy
    Discovery date19 May 2021
    Orbital characteristics [5] : 16 
    49.9±1.0 km
    32.972823  h
    Inclination 30°±3° wrt ecliptic [lower-alpha 2]
    Satellite of 4337 Arecibo
    Physical characteristics
    Mean diameter
    		13±1.5 km [4] : 4 
    Mean density
    		<1.3 g/cm3 [5] : 17 

      Arecibo hosts a relatively large minor-planet moon with a size about half its diameter, forming a binary system. This unnamed satellite orbits closely at an orbital radius of 50 km (31 mi) from the primary body of the Arecibo system, completing a full revolution in about 33 hours or 1.4 days. [5] : 16  It was discovered by Australian amateur astronomers David Gault and Peter Nosworthy while observing Arecibo occulting a star on 19 May 2021, and was confirmed in another occultation on 9 June 2021. [9] [lower-alpha 1]

      Orbit

      The observed angular separation between the satellite and primary body in the 19 May and 9 June 2021 occultations were 25.5±1.0 and 32.8±0.7 milliarcseconds, respectively. [14] [4] In July 2021, Nolthenius presented a preliminary analysis suggesting that the satellite's orbital radius should lie in the range of 100–293 km (62–182 mi), based on an assumed system density of 1.9 g/cm3 and an outer orbital stability limit set by Jupiter's gravitational influence. [18] : 39  Because no photometric measurements of Arecibo's rotation period were available at that time, constraints on the satellite's orbital period were solely limited to the three occultations observed in 2021, which suggested periods of 20 days and its shorter-period aliases of 10 days, 5 days, and 2.5 days. [18] : 39 

      On 13 June 2022, a team of European astronomers led by Paolo Tanga, on behalf of the European Space Agency, published a proof-of-concept analysis of the Arecibo system using high-precision astrometry and photometry from the Gaia mission, as part of its third data release. [19] [5] : 16  They found that Arecibo exhibits periodic oscillations in brightness and position that are both compatible with a period of 32.972823 hours (1.3738676 d), consistent with earlier ground-based photometry from July 2021 and establishing the satellite's orbital period. [6] [5] : 16  They determined a smaller orbital radius of 49.9 ± 1.0 km (31.01 ± 0.62 mi) and an inclination of 30°±3° with respect to the ecliptic, precisely coinciding with the satellite's positions observed in the May and June 2021 occultations. [5] : 16  [lower-alpha 2] Given the satellite's close proximity to the primary body and coincidence of brightness and position oscillation periods, the satellite is likely in synchronous orbit with the primary's rotation period. [5] : 16 

      Physical characteristics

      Periodic oscillation in Arecibo's position measured by the Gaia spacecraft, signifying the presence of a large orbiting satellite AreciboOrbitalFitGaiaDR3.jpg
      Periodic oscillation in Arecibo's position measured by the Gaia spacecraft, signifying the presence of a large orbiting satellite

      The initial detection of the satellite in the 19 May 2021 occultation provided poor constraints on its size due to close spacing between the observers' sites. [14] The 9 June 2021 occultation proved to be more reliable with wider spacing between observer sites, providing a best-fit satellite diameter of 13 ± 1.5 km (8.08 ± 0.93 mi) for an assumed spherical shape for the satellite. [4] : 4  Given this diameter estimate, this makes the satellite about half the size of the primary body in the Arecibo system. [5] : 16 

      The satellite is massive enough to induce measurable positional wobbling of the Arecibo primary, although with an unexpectedly low amplitude of up to 2.7 milliarcseconds from Gaia's view, or 8.5% of the maximum observed angular separation between the satellite and primary. [5] : 16  This small positional wobbling of the Arecibo primary implies a very low satellite-to-primary mass ratio relative to the satellite-to-primary diameter ratio, which could either be explained by a highly flattened shape or a very low density for the satellite. [5] : 17  Tanga and collaborators favor the high flattening scenario as it yields more realistic density values and can explain the infrared underestimation of the primary's diameter. [5] : 17  In this case, the occultation-derived satellite diameter would represent its maximum shape extent and its minimum possible density would be 1 g/cm3, which is expected for a highly porous asteroid of the Themis family. [5] : 17 

      Notes

      1. 1 2 Asteroid 2258 Viipuri may also have a putative satellite that was solely detected in two single-chord occultations from 3 August 2013 and 19 September 2018, but the timespan between these detections is too sparse to determine the satellite's orbital motion. [18] : 40 
      2. 1 2 3 Tanga et al. (2022) give the satellite's orbit pole orientation in terms of ecliptic coordinates, where λ is ecliptic longitude and β is ecliptic latitude. [5] : 16 β is the angular offset from the ecliptic plane and inclination i with respect to the ecliptic is the angular offset from the ecliptic north pole at β = +90°; i with respect to the ecliptic would be the complement of β. [17] Therefore, given β = 60°, i = 90° – 60° = 30° from the ecliptic.

      Related Research Articles

      <span class="mw-page-title-main">88 Thisbe</span> Main-belt asteroid

      Thisbe, minor planet designation 88 Thisbe, is the 13th largest main-belt asteroid. It was discovered by C. H. F. Peters on June 15, 1866, and named after Thisbe, heroine of a Roman fable. This asteroid is orbiting the Sun at a distance of 2.768 AU with a period of 4.60 years and an orbital eccentricity (ovalness) of 0.165. The orbital plane is inclined at an angle of 5.219° to the ecliptic.

      <span class="mw-page-title-main">694 Ekard</span>

      694 Ekard is a minor planet orbiting the Sun that was discovered by American astronomer Joel Hastings Metcalf on November 7, 1909. The asteroid's name comes from the reverse spelling of Drake University in Des Moines, Iowa, where Seth Barnes Nicholson and his wife calculated its orbit.

      659 Nestor is a dark Jupiter trojan from the Greek camp, approximately 110 kilometers in diameter. It was discovered on 23 March 1908, by German astronomer Max Wolf at Heidelberg Observatory in southern Germany, and named after King Nestor from Greek mythology. The carbonaceous Jovian asteroid belongs to the 20 largest Jupiter trojans and has a rotation period of 15.98 hours.

      <span class="mw-page-title-main">911 Agamemnon</span> Jupiter trojan

      911 Agamemnon, provisional designation 1919 FD, is a large Jupiter trojan and a suspected binary asteroid from the Greek camp, approximately 168 kilometers in diameter. It was discovered on 19 March 1919, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany. The dark D-type asteroid is one of the largest Jupiter trojans and has a rotation period of 6.6 hours. It is named after the Greek King Agamemnon, a main character of the Iliad.

      <span class="mw-page-title-main">936 Kunigunde</span>

      936 Kunigunde is a dark Themistian asteroid from the outer regions of the asteroid belt, approximately 40 kilometers in diameter. It was discovered on 8 September 1920, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory. The carbonaceous B-type asteroid has a rotation period of 9.4 hours. It was named "Kunigunde", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

      976 Benjamina is a dark background asteroid from the outer regions of the asteroid belt, approximately 81 kilometers in diameter. It was discovered on 27 March 1922, by Russian-French astronomer Benjamin Jekhowsky at the Algiers Observatory in North Africa. The large X/D-type asteroid has a rotation period of 9.7 hours and is likely regular in shape. It was named after the discoverer's son.

      1139 Atami, provisional designation 1929 XE, is a stony asteroid and sizable Mars-crosser, as well as a synchronous binary system near the innermost region of the asteroid belt, approximately 9 kilometers in diameter. It was discovered on 1 December 1929, by Japanese astronomers Okuro Oikawa and Kazuo Kubokawa at the Tokyo Astronomical Observatory near Tokyo. It was named after the Japanese city of Atami. It has the lowest Minimum orbit intersection distance (MOID) to Mars of any asteroid as large as it, its orbit intersecting only 0.03 astronomical units from the planet.

      2153 Akiyama, provisional designation 1978 XD, is a carbonaceous Themistian asteroid from the outer region of the asteroid belt, approximately 17 kilometers in diameter.

      4151 Alanhale, provisional designation 1985 HV1, is a carbonaceous Themistian asteroid from the outer region of the asteroid belt, approximately 19 kilometers in diameter. It was discovered by the American astronomer couple Carolyn and Eugene Shoemaker at the U.S. Palomar Observatory, California, on 24 April 1985. It was named for American astronomer Alan Hale.

      6084 Bascom, provisional designation 1985 CT, is a binary Phocaea asteroid from the inner regions of the asteroid belt, approximately 6.3 kilometers in diameter. It was discovered on 12 February 1985, by American astronomer couple Carolyn and Eugene Shoemaker at Palomar Observatory in California. It is named after American geologist Florence Bascom. Its satellite measures approximately 2.3 kilometers and has an orbital period of 43.51 hours.

      4029 Bridges, provisional designation 1982 KC1, is a stony asteroid and binary system from the middle regions of the asteroid belt, approximately 8 kilometers in diameter.

      2197 Shanghai, provisional designation 1965 YN, is a carbonaceous Themistian asteroid from the outer region of the asteroid belt, approximately 22 kilometers in diameter.

      4176 Sudek, provisional designation 1987 DS, is a Themistian asteroid from the outer regions of the asteroid belt, approximately 17 kilometers in diameter. It was discovered on 24 February 1987, by Czech astronomer Antonín Mrkos at the Kleť Observatory in the Czech Republic. The presumed C-type asteroid has a rotation period of 8.16 hours. It was named in memory of Czech photographer Josef Sudek.

      2882 Tedesco, provisional designation 1981 OG, is a Themistian asteroid from the outer regions of the asteroid belt, approximately 22 kilometers in diameter. It was discovered on 26 July 1981, by astronomer Edward Bowell at the Anderson Mesa Station near Flagstaff, Arizona. The likely elongated C-type asteroid has a rotation period of 19.8 hours. It was named for American astronomer Ed Tedesco.

      <span class="mw-page-title-main">3962 Valyaev</span>

      3962 Valyaev is a dark Themistian asteroid from the outer region of the asteroid belt. The presumed C-type asteroid has a rotation period of 16.4 hours and measures approximately 15 kilometers in diameter. It was discovered on 8 February 1967, by Russian astronomer Tamara Smirnova at Nauchnyj on the Crimean peninsula, and later named after Russian astronomer Valerij Valyaev.

      1259 Ógyalla, provisional designation 1933 BT, is a Themistian asteroid from the outer region of the asteroid belt, approximately 32 kilometers in diameter. It was discovered on 29 January 1933, by German astronomer Karl Reinmuth at Heidelberg Observatory in southwest Germany. The asteroid was named for the Hurbanovo Observatory.

      (450894) <span class="nowrap">2008 BT<sub>18</sub></span>

      (450894) 2008 BT18 is a sub-kilometer asteroid and synchronous binary system, classified as near-Earth object and potentially hazardous asteroid of the Apollo group. It was discovered on 31 January 2008, by the LINEAR program at Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, United States. The eccentric asteroid measures approximately 600 meters in diameter and has a composition of a basaltic achondrite.

      <span class="mw-page-title-main">(35107) 1991 VH</span>

      (35107) 1991 VH is a binary near-Earth asteroid and potentially hazardous asteroid of the Apollo group. It was discovered on 9 November 1991, by Australian astronomer Robert McNaught at Siding Spring Observatory. This binary system is composed of a roughly-spheroidal primary body about one kilometre in diameter, and an elongated natural satellite less than half a kilometre in diameter. The 1991 VH system is unusual for its dynamically excited state; the satellite has a tumbling, non-synchronous rotation that chaotically exchanges energy and angular momentum with its precessing, eccentric orbit. This asteroid system was one of the two targets of NASA's upcoming Janus Mayhem mission, until the delay of the rocket launch made both targets inaccessible.

      <span class="nowrap">(285263) 1998 QE<sub>2</sub></span> Near-Earth asteroid

      (285263) 1998 QE2, provisional designation 1998 QE2, is a dark asteroid and synchronous binary system, classified as near-Earth object and potentially hazardous asteroid of the Amor group, approximately 3 kilometers in diameter. It was discovered on 19 August 1998, by astronomers of the LINEAR program at Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, in the United States. Its sub-kilometer minor-planet moon was discovered by radar on 30 May 2013.

      <span class="nowrap">2020 BX<sub>12</sub></span> Binary near-Earth asteroid

      2020 BX12 is a sub-kilometer binary asteroid, classified as a near-Earth asteroid and potentially hazardous object of the Apollo group. It was discovered on 27 January 2020 by the Asteroid Terrestrial-impact Last Alert System survey at the Mauna Loa Observatory during its approach to Earth of 0.02915 AU (4.361 million km; 11.34 LD). Radar observations of the asteroid were carried out by the Arecibo Observatory on 4 February 2020, revealing a natural satellite orbiting 360 m (1,180 ft) from the primary body.

      References

      1. 1 2 3 4 5 6 7 "4337 Arecibo (1985 GB)" (2021-09-24 last obs.). Jet Propulsion Laboratory. Archived from the original on 7 February 2022. Retrieved 16 June 2022.
      2. 1 2 3 4 5 6 7 "(4337) Arecibo = 1933 HE = 1979 FR3 = 1979 HG2 = 1985 GB". Minor Planet Center. Archived from the original on 4 October 2016. Retrieved 16 June 2022.
      3. 1 2 3 4 5 6 "LCDB Data for (4337) Arecibo". Asteroid Lightcurve Database (LCDB). Collaborative Asteroid Lightcurve Link. Archived from the original on 29 June 2022. Retrieved 16 June 2022.
      4. 1 2 3 4 5 6 7 8 9 10 11 12 Gault, David; Nosworthy, Peter; Nolthenius, Richard; Bender, Kirk; Herald, Dave (January 2022). "A New Satellite of 4337 Arecibo Detected and Confirmed by stellar Occultation". The Minor Planet Bulletin. 49 (1): 3–5. Bibcode:2022MPBu...49....3G. Archived from the original on 29 June 2022. Retrieved 16 June 2022.
      5. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Tanga, P.; Pauwels, T.; Mignard, F.; Muinonen, K.; Cellino, A.; David, P.; et al. (June 2022). "Gaia Data Release 3: the Solar System survey" (PDF). Astronomy & Astrophysics. arXiv: 2206.05561 . doi: 10.1051/0004-6361/202243796 . Archived (PDF) from the original on 13 June 2022. Retrieved 16 June 2022.
      6. 1 2 3 Behrend, Raoul. "Asteroids and comets rotation curves, CdR & Regular variable stars light curves, CdL". Observatoire de Genève. Archived from the original on 3 August 2003. Retrieved 16 June 2022.
      7. 1 2 Mainzer, Amy K.; Bauer, James M.; Cutri, Roc M.; Grav, Tommy; Kramer, Emily A.; Masiero, Joseph R.; et al. (2019). "NEOWISE Diameters and Albedos V2.0". PDS Small Bodies Node. Bibcode:2019PDSS..251.....M. doi: 10.26033/18S3-2Z54 . Archived from the original on 16 June 2022. Retrieved 16 June 2022.
      8. 1 2 Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv: 1606.08923 . Bibcode:2016AJ....152...63N. doi: 10.3847/0004-6256/152/3/63 . S2CID   119289027. 63.
      9. 1 2 3 4 5 6 7 Nosworthy, Peter; Gault, Dave. "Arecibo Moon Discovery". Hazelbrook Observatory. Archived from the original on 28 January 2022. Retrieved 16 June 2022.
      10. 1 2 "M. P. C. 9671" (PDF). Minor Planet Circulars. Minor Planet Center (9671): 71. 4 May 1985. Archived (PDF) from the original on 10 August 2017. Retrieved 17 June 2022.
      11. ↑ "M. P. C. 10039" (PDF). Minor Planet Circulars. Minor Planet Center (10039): 59. 29 September 1985. Archived (PDF) from the original on 10 August 2017. Retrieved 16 June 2022.
      12. ↑ "M. P. C. 15690" (PDF). Minor Planet Circulars. Minor Planet Center (15690): 90. 11 January 1990. Archived (PDF) from the original on 24 February 2013. Retrieved 16 June 2022.
      13. ↑ "M. P. C. 16445" (PDF). Minor Planet Circulars. Minor Planet Center. 8 June 1990. p. 155. Archived (PDF) from the original on 23 June 2021. Retrieved 16 June 2022.
      14. 1 2 3 4 "CBET 4981 : (4337) ARECIBO". Central Bureau Electronic Telegrams. Central Bureau for Astronomical Telegrams (4981). 20 June 2021. Archived from the original on 28 January 2022. Retrieved 16 June 2022.
      15. 1 2 Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families". Asteroids IV. pp. 297–321. arXiv: 1502.01628 . Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN   9780816532131. S2CID   119280014.
      16. ↑ Houdart, Robert. "Telescope Limiting Magnitude Calculator". Cruxis. Archived from the original on 26 May 2021. Retrieved 17 June 2022.
      17. ↑ "Coordinate transformations". Astronomy and Astrophysics. European Southern Observatory. January 1998. Archived from the original on 17 June 2021. Retrieved 17 June 2022.
      18. 1 2 3 Nugent, Richard (January 2022). "The International Occultation Timing Association's 39th Annual Meeting, 2021 July 17-18 via Zoom Online" (PDF). Journal for Occultation Astronomy. 12 (1): 38–40. Archived (PDF) from the original on 3 April 2022. Retrieved 16 June 2022.
      19. ↑ Roegiers, Tineke; Tanga, Paolo; Galluccio, Laurent (13 June 2022). "Is it a Solar System object?". European Space Agency. Archived from the original on 14 June 2022. Retrieved 16 June 2022.
      This page is based on this Wikipedia article
      Text is available under the CC BY-SA 4.0 license; additional terms may apply.
      Images, videos and audio are available under their respective licenses.