5477 Holmes

5477 Holmes, provisional designation 1989 UH2, is a Hungaria asteroid and binary system from the innermost regions of the asteroid belt, approximately 3 kilometers (2 miles) in diameter. It was discovered on 27 October 1989, by American astronomer Eleanor Helin at the Palomar Observatory in California.[1] The presumed E-type asteroid is likely spherical in shape and has a short rotation period of 2.99 hours.[3] It was named for American amateur astronomer Robert Holmes.[1] The discovery of its 1-kilometer-sized minor-planet moon was announced in November 2005.[5][6]

5477 Holmes
Discovery [1]
Discovered byE. F. Helin
Discovery sitePalomar Obs.
Discovery date27 October 1989
Designations
(5477) Holmes
Named after
Robert Holmes [1]
(American astronomer)
1989 UH2
main-belt · (inner) [2]
Hungaria [1][3][4]
Orbital characteristics [2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc27.60 yr (10,082 d)
Aphelion2.0613 AU
Perihelion1.7732 AU
1.9172 AU
Eccentricity0.0751
2.65 yr (970 d)
295.23°
0° 22m 16.68s / day
Inclination22.552°
49.112°
290.30°
Known satellites1 (D: 1.09 km P: 24.4 h)[3][5][6]
Physical characteristics
Mean diameter
2.95±0.13 km (derived)[5]
3.147±0.137 km[7][8]
3.21 km (taken)[3]
3.215 km[9]
2.9932±0.0002 h[10][lower-alpha 1]
2.9940±0.0002 h[11]
2.99401±0.00007 h[12]
2.99408±0.00007 h[13]
2.9943±0.0002 h[6]
0.2849[9]
0.310±0.038[7][8]
E (assumed)[3]
13.99±0.03 (R)[12]
14.0[2]
14.26±0.54[14]
14.4[8][13]
14.445[3][9]

    Orbit and classification

    Holmes is a core member of the Hungaria family (003),[4] a large family of bright asteroids that forms the innermost dense concentration of asteroids in the Solar System, as the Mars-crosser and near-Earth populations are much more sparse. The family is part of the larger dynamical group with the same name.[1][3] It orbits the Sun in the innermost asteroid belt at a distance of 1.8–2.1 AU once every 2 years and 8 months (970 days; semi-major axis of 1.92 AU). Its orbit has an eccentricity of 0.08 and an inclination of 23° with respect to the ecliptic.[2] The body's observation arc begins with its official discovery observation at Palomar in October 1989.[1]

    Physical characteristics

    Holmes is an assumed E-type asteroid,[3] which agrees with the overall spectral type for members of the Hungaria family.[15]:23

    Rotation period

    Since 2005, several rotational lightcurves of Holmes have been obtained from photometric observations by Brian Warner and Petr Pravec in collaboration with other astronomers.[6][10][11][12][13][lower-alpha 1] Analysis of the best-rated lightcurve gave a well-defined rotation period of 2.9940 hours with a consolidated brightness amplitude between 0.10 and 0.12 magnitude, which indicates that the body has a nearly spherical shape (U=3).[3][11] The asteroid's short period is near that of a fast rotator.

    Diameter and albedo

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), Holmes measures 3.147 kilometers in diameter and its surface has an albedo of 0.31,[7][8] while the Collaborative Asteroid Lightcurve Link adopts Petr Pravec's revised WISE-data, that is, an albedo of 0.2849 and a diameter of 3.21 kilometers based on an absolute magnitude of 14.445.[3][9] Johnston's Archive derives a diameter of 2.95 and 3.15 kilometers for the primary only and for the combined system, respectively.[5]

    Satellite

    The photometric observations obtained by Brian Warner and collaborators during 2–12 November 2005,[13] revealed that Holmes is a synchronous binary asteroid with a minor-planet moon orbiting it every 24.4 hours at an estimated average distance of 6.7 km. The discovery was announced immediately on 15 November 2005.[6] The mutual occultation events indicated the presence of a satellite 37% the size of its primary, which translates into an estimated diameter of 1.09–1.19 kilometers depending on the underlying size estimate of the primary.[3][5]

    Naming

    This minor planet was named after American amateur astronomer Robert E. Holmes Jr (born 1956), who directs the Astronomical Research Observatory (H21) in Westfield, Illinois.[1] The official naming citation was suggested by Sergio Foglia and published by the Minor Planet Center on 18 February 2011 (M.P.C. 73983).[16]

    Notes
    1. Lightcurve plot of 5477 Holmes, Palmer Divide Observatory, Brian D. Warner (2012). Rotation period 2.9932±0.0002 hours with a brightness amplitude of 0.10±0.01 mag. The second plot for the orbital period of the satellite gives a period of 24.37±0.01 hours. Quality code is 3. Summary figures at the LCDB.

    References
    1. "5477 Holmes (1989 UH2)". Minor Planet Center. Retrieved 17 May 2018.
    2. "JPL Small-Body Database Browser: 5477 Holmes (1989 UH2)" (2017-06-04 last obs.). Jet Propulsion Laboratory. Retrieved 17 May 2018.
    3. "LCDB Data for (5477) Holmes". Asteroid Lightcurve Database (LCDB). Retrieved 17 May 2018.
    4. "Asteroid 5477 Holmes". Small Bodies Data Ferret. Retrieved 15 May 2018.
    5. Johnston, Wm. Robert (21 September 2014). "Asteroids with Satellites Database – (5477) Holmes". Johnston's Archive. Retrieved 17 May 2018.
    6. Warner, B. D.; Pravec, P.; Kusnirak, P.; Cooney, W.; Gross, J.; Terrell, D.; et al. (November 2005). "CBET #288 – (5477) 1989 UH_2". Central Bureau Electronic Telegrams. 288 (288): 1. Bibcode:2005CBET..288....1W. Retrieved 17 May 2018.
    7. Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68.
    8. Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. (catalog)
    9. Pravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus. 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026.
    10. Warner, Brian D.; Stephens, Robert D.; Coley Daniel (October 2012). "Lightcurve for the Hungaria Binary 5477 Holmes". The Minor Planet Bulletin. 39 (4): 230–231. Bibcode:2012MPBu...39..230W. ISSN 1052-8091.
    11. Pravec, P.; Scheirich, P.; Kusnirák, P.; Hornoch, K.; Galád, A.; Naidu, S. P.; et al. (March 2016). "Binary asteroid population. 3. Secondary rotations and elongations". Icarus. 267: 267–295. Bibcode:2016Icar..267..267P. doi:10.1016/j.icarus.2015.12.019.
    12. Pravec, P.; Scheirich, P.; Vokrouhlický, D.; Harris, A. W.; Kusnirák, P.; Hornoch, K.; et al. (March 2012). "Binary asteroid population. 2. Anisotropic distribution of orbit poles of small, inner main-belt binaries". Icarus. 218 (1): 125–143. Bibcode:2012Icar..218..125P. doi:10.1016/j.icarus.2011.11.026.
    13. Warner, Brian D.; Pravec, Petr; Kusnirak, Peter; Harris, Alan W.; Cooney, Walter R., Jr.; Gross, John; et al. (April 2011). "Lightcurves from the Initial Discovery of Four Hungaria Binary Asteroids". The Minor Planet Bulletin. 38 (2): 107–109. Bibcode:2011MPBu...38..107W. ISSN 1052-8091.
    14. 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.
    15. 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.
    16. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 17 May 2018.

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