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20325 Julianoey (provisional designation 1998 HO₂₇) is a Vestian asteroid and a synchronous binary system from the inner regions of the asteroid belt, approximately 5 kilometers (3 miles) in diameter. It was discovered on 21 April 1998, by astronomers of the Spacewatch survey at Kitt Peak National Observatory near Tucson, Arizona. The asteroid was named after Australian photometrist Julian Oey. The discovery of its minor-planet moon was announced in December 2014.

Orbit and classification

Julianoey is a member of the Vesta family (401), the second largest family in the asteroid belt, named after 4 Vesta. However, it is a non-family asteroid of the main belt's background population when applying the Hierarchical Clustering Method to its proper orbital elements.

It orbits the Sun in the inner asteroid belt at a distance of 2.2–2.6 AU once every 3 years and 8 months (1,340 days; semi-major axis of 2.38 AU). Its orbit has an eccentricity of 0.08 and an inclination of 6° with respect to the ecliptic. The body's observation arc begins with a precovery taken at Palomar Observatory in May 1954, almost 44 years prior to its official discovery observation at Kitt Peak.

Physical characteristics

Julianoey is an assumed stony S-type asteroid.

Rotation period

In December 2014, a rotational lightcurve of Julianoey was obtained from photometric observations by Donald Pray and several other astronomers across the world. Lightcurve analysis gave a well-defined rotation period of 3.24474 hours with a brightness amplitude of 0.13 magnitude (U=3).

Satellite

The photometric observations from December 2014 also revealed that Julianoey is a synchronous binary asteroid with a minor-planet moon orbiting it every 23.54 hours. The satellite, provisionally designated S/2014 (20325) 1, measures approximately 1.42 kilometers in diameter and its orbit has an estimated semi-major axis of 10 kilometers. The discovery was announced on 24 December 2014.

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Julianoey measures 4.942 kilometers in diameter and its surface has a high albedo of 0.416. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and consequently calculates a larger diameter of 6.81 kilometers based on an absolute magnitude of 13.2.

Numbering and naming

This minor planet was numbered on 9 January 2001 (M.P.C. 41904). It was named after Julian Oey (born 1964), a well-known asteroid photometrist, observing from Australia. He was the principal investigator that led to the discovery of four binary asteroids: 2691 Sersic, 3868 Mendoza, 10208 Germanicus and 15268 Wendelinefroger.

As of 2017, he is also credited as co-discoverer of the following binary asteroids: 1338 Duponta, 1798 Watts, 2121 Sevastopol, 2343 Siding Spring, 2478 Tokai, 4541 Mizuno, 5112 Kusaji, 5481 Kiuchi, 6186 Zenon, 8306 Shoko, 8474 Rettig, 12326 Shirasaki, (15700) 1987 QD, (32039) 2000 JO₂₃, (99913) 1997 CZ₅ and (357439) 2004 BL86.

The naming was suggested by astronomers Alan Harris and Petr Pravec. The official naming citation was published by the Minor Planet Center on 5 June 2016 (M.P.C. 100606; listed on 20 June 2016).

See also

• Minor-planet moon § Asteroid belt

References

1. ^ "JPL Small-Body Database Browser: 20325 Julianoey (1998 HO27)" (2017-11-02 last obs.). Jet Propulsion Laboratory. Retrieved 28 November 2017.
2. ^ "20325 Julianoey (1998 HO27)". Minor Planet Center. Retrieved 28 November 2017.
3. ^ "LCDB Data for (20325) Julianoey". Asteroid Lightcurve Database (LCDB). Retrieved 28 November 2017.
4. ^ "Asteroid 20325 Julianoey – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 29 October 2019.
5. ^ Johnston, Wm. Robert (19 February 2017). "Asteroids with Satellites Database – (20325) Julianoey". Johnston's Archive. Retrieved 28 November 2017.
6. ^ Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 28 November 2017.
7. ^ Pray, D.; Pravec, P.; Benishek, V.; Pollock, J.; Cooney, W.; Gross, J.; et al. (December 2014). "(20325) 1998 HO_27". Central Bureau Electronic Telegrams (4039). Bibcode:2014CBET.4039....1P. Retrieved 28 November 2017.
8. Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 28 November 2017.
9. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 28 November 2017.
10. ^ "Discoveries – Announcements". Blue Mountains Observatory. Retrieved 28 November 2017.

External links

• (20325) Julianoey at Blue Mountains Observatory website
• Julian Oey, 2018 Shoemaker NEO Grant Recipients
• Asteroids with Satellites, Robert Johnston, johnstonsarchive.net
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (20001)-(25000) – Minor Planet Center
• 20325 Julianoey at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 20325 Julianoey at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• Vesta asteroids
• Discoveries by the Spacewatch project
• Named minor planets
• Binary asteroids
• Astronomical objects discovered in 1998