10645 Brač

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10645 Brač
Discovery [1]
Discovered by K. Korlević
Discovery site Višnjan Obs.
Discovery date 14 March 1999
MPC designation (10645) Brač
Named after
Brač (Croatian island)[2]
1999 ES4 · 1962 TN
1968 BF · 1975 TJ1
1980 YK · 1986 EH5
1988 SX4
main-belt · Eunomia[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 54.67 yr (19,968 days)
Aphelion 3.1430 AU
Perihelion 2.1725 AU
2.6578 AU
Eccentricity 0.1826
4.33 yr (1,583 days)
0° 13m 39s / day
Inclination 12.520°
Physical characteristics
Dimensions 9.60 km (calculated)[3]
10.26±0.11 km[4]
2.785±0.005 h[5]
2.78592±0.00003 h[6]
0.21 (assumed)[3]
S[3] · LS[7]
12.5[1] · 12.4[3] · 12.3[4] · 12.41±0.50[7]

10645 Brač, provisional designation 1999 ES4, is a stony Eunomia asteroid from the central region of the asteroid belt, approximately 10 kilometers in diameter. It was discovered on 14 March 1999, by Croatian astronomer Korado Korlević at Višnjan Observatory, and named after the Croatian island of Brač.[2][8]

Classification and orbit[edit]

The asteroid is a member of the Eunomia family, a large group of S-type asteroids and the most prominent family in the intermediate main-belt. It orbits the Sun at a distance of 2.2–3.1 AU once every 4 years and 4 months (1,583 days). Its orbit has an eccentricity of 0.18 and an inclination of 13° with respect to the ecliptic.[1] The first precovery was taken at the U.S. Goethe Link Observatory in 1962, extending the asteroid's observation arc by 37 years prior to discovery.[8]

Physical characteristics[edit]

In October 2014, photometric observations by Italian astronomer Silvano Casulli gave a rotational lightcurve with a period of 2.78592±0.00003 hours and a brightness amplitude of 0.31 in magnitude (U=3-).[6] Three weeks later, a second lightcurve was obtained at the U.S. Etscorn Campus Observatory in New Mexico, rendering a concurring period of 2.785±0.005 with an identical variation in brightness (U=3-).[5]

According to the survey carried out by NASA's space-based Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid measures 10.3 kilometers in diameter and its surface has an albedo of 0.202±0.038,[4] while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.21 and calculates a diameter of 9.6 kilometers.[3] A large-scale survey by Pan-STARRS (PS1) assigns an LS-type, an intermediary spectral type between the common, stony S-types and the rather rare and reddish L-type asteroids.[7]


This minor planet was named after the Croatian island of Brač, the largest Dalmatian island in the Adriatic sea, and the place where the Blaca hermitage Observatory is located.[2] The approved naming citation was published by the Minor Planet Center on 15 December 2005 (M.P.C. 55720).[9]


  1. ^ a b c d "JPL Small-Body Database Browser: 10645 Brac (1999 ES4)" (2017-06-05 last obs.). Jet Propulsion Laboratory. Retrieved 5 July 2017. 
  2. ^ a b c Schmadel, Lutz D. (2006). Dictionary of Minor Planet Names – (10645) Brač, Addendum to Fifth Edition: 2003–2005. Springer Berlin Heidelberg. p. 55. ISBN 978-3-540-34360-8. Retrieved 12 April 2016. 
  3. ^ a b c d e f "LCDB Data for (10645) Brac". Asteroid Lightcurve Database (LCDB). Retrieved 17 May 2016. 
  4. ^ a b c d 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:1209.5794Freely accessible. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 17 May 2016. 
  5. ^ a b Klinglesmith, Daniel A.; DeHart, Austin; Hanowell, Jesse; Hendrickx, Sebastian (April 2015). "Asteroids at Etscorn Campus Observatory: 2014 September - December". The Minor Planet Bulletin. 42 (2): 101–104. Bibcode:2015MPBu...42..101K. ISSN 1052-8091. Retrieved 17 May 2016. 
  6. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (10645) Brac". Geneva Observatory. Retrieved 17 May 2016. 
  7. ^ a b c 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:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 17 May 2016. 
  8. ^ a b "10645 Brac (1999 ES4)". Minor Planet Center. Retrieved 12 April 2016. 
  9. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 17 May 2016. 

External links[edit]