Eurybates was discovered on 19 September 1973, by Dutch astronomers Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by Tom Gehrels at the Palomar Observatory in California, United States. In 1951, it was first observed as 1954 CB at the Goethe Link Observatory, extending the asteroid's observation arc by 22 years prior to its official discovery observation at Palomar.[1] Since the discovery of 588 Achilles by Max Wolf in 1906, more than 7,000 Jupiter trojans, with nearly 4,600 bodies in the Greek camp, have already been discovered.[6]
Palomar–Leiden Trojan survey
While the discovery date aligns with the second Palomar–Leiden Trojan survey, Eurybates has not received a "T-2" prefixed survey designation, which was assigned for the discoveries made by the fruitful collaboration between the Palomar and Leiden observatories in the 1960s and 1970s. Gehrels used Palomar's Samuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory where astrometry was carried out. The trio are credited with the discovery of several thousand asteroids.[12]
Eurybates has an axial tilt of 150° with respect to the ecliptic, making it a retrograde rotator.[9]
Diameter and albedo
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Eurybates measures between 63.89 and 72.14 kilometers in diameter and its surface has an albedo between 0.052 and 0.060.[18][19][20] The Collaborative Asteroid Lightcurve Link agrees with IRAS, and derives an albedo of 0.0491 and a diameter of 72.08 kilometers with an absolute magnitude of 9.6.[5]
100+ largest Jupiter trojans
Largest Jupiter Trojans by survey(A) (mean-diameter in kilometers; YoD: Year of Discovery)
Note: missing data was completed with figures from the JPL SBDB (query) and from the LCDB (query form) for the WISE/NEOWISE and SIMPS catalogs, respectively. These figures are given in italics. Also, listing is incomplete above #100.
Animation of Lucy's trajectory around Sun Lucy· Sun· Earth· 52246 Donaldjohanson · 3548 Eurybates· 21900 Orus· 617 Patroclus
Eurybates is planned to be visited by the Lucy spacecraft which launched in 2021.[22] The flyby is scheduled for 12 August 2027, and will approach the asteroid to a distance of 1,000 km (620 mi) at a relative velocity of 5.8 km/s (13,000 mph) and a solar phase angle of 81°.[11]
Satellite
"Queta (moon)" redirects here. For the Olympic athlete, see Enriqueta Basilio.
Queta
Discovery images of Queta taken by Hubble on 12–14 September 2018
Eurybates has one known satellite, named Queta after Mexican Olympic athlete Enriqueta Basilio.[26]Provisionally designated S/2018 (3548) 1, the satellite was discovered by Keith S. Noll and colleagues in images taken with the Hubble Space Telescope in September 2018.[25][27] Subsequent follow-up observations later confirmed the satellite's existence, and the discovery was announced on 9 January 2020. The satellite was given the name Queta on 15 October 2020, in accordance with the International Astronomical Union's Olympic athlete naming convention for small Jupiter trojans (H > 12). In the naming citation, Enriqueta Basilio was recognized as the first woman torchbearer at the 1968 Summer Olympics, analogous to the role of heralds like Eurybates.[26]
Queta is extremely faint, with an apparent magnitude of ~26.77.[25] It is at least 6,000 times fainter than Eurybates, suggesting that Queta is likely very small, about 1.2 ± 0.4 km (0.75 ± 0.25 mi) in diameter if it has the same albedo as Eurybates.[24] The satellite has an orbital period of 82.46±0.06 days, with a semi-major axis of 2,350 ± 11 km (1,460.2 ± 6.8 mi) and low eccentricity of 0.125±009.[10] It is probably a fragment of Eurybates since it is part of a known collisional family.[28][10] The presence of the satellite does not pose any adverse effects on the Lucy mission, though it provides an additional object for the spacecraft to study during its flyby in 2027.[29][28]
^Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System – IRAS-A-FPA-3-RDR-IMPS-V6.0. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 15 June 2018.
