(15692) 1984 RA

(15692) 1984 RA, provisional designation 1984 RA, is a Hungaria asteroid from the innermost regions of the asteroid belt, approximately 2 kilometers (1.2 miles) in diameter. It was discovered on 1 September 1984, by Italian astronomer Maria Barucci at the Palomar Observatory in California, United States.[1] The presumed E-type asteroid has a longer-than average rotation period of 37.4 hours and possibly an elongated shape.[3]

(15692) 1984 RA
Discovery [1]
Discovered byM. Barucci
Discovery sitePalomar Obs.
Discovery date1 September 1984
Designations
(15692) 1984 RA
1984 RA · 1986 JT1
1992 SZ26
main-belt · (inner)[2]
Hungaria [1][3][4]
Orbital characteristics [2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc41.44 yr (15,135 d)
Aphelion2.1225 AU
Perihelion1.7302 AU
1.9264 AU
Eccentricity0.1018
2.67 yr (977 d)
138.59°
0° 22m 6.96s / day
Inclination23.217°
142.60°
273.05°
Physical characteristics
Mean diameter
1.728±0.273 km[5][6]
2.43 km (calculated)[3]
37.44±0.05 h[7][lower-alpha 1]
0.30 (assumed)[3]
0.780±0.146[5][6]
E (assumed)[3]
14.7[6]
14.85±0.97[8]
14.9[2]
15.0[3]

    Orbit and classification

    1984 RA is a bright core member of the Hungaria family (003),[4] a large family of three thousand asteroids located within the dynamical group with the same name.[1][3] Hungarias form the innermost dense concentration of asteroids in the Solar System; they are inside the asteroid belt's core region, sometimes considered a completely independent population.[9]

    The asteroid orbits the Sun in the innermost asteroid belt at a distance of 1.7–2.1 AU once every 2 years and 8 months (977 days; semi-major axis of 1.93 AU). Its orbit has an eccentricity of 0.10 and an inclination of 23° with respect to the ecliptic.[2] The body's observation arc begins with a precovery found in the Digitized Sky Survey and taken at the Siding Spring Observatory in November 1977, almost 7 years prior to its official discovery observation at Palomar.[1]

    Physical characteristics

    1984 RA is an assumed E-type asteroid, known for their high albedos, typically around 0.4.[3]

    Rotation period

    In July 2013, a rotational lightcurve of this asteroid was obtained from photometric observations by American astronomer Brian Warner at the Palmer Divide Station (U82) in California. Lightcurve analysis gave a long rotation period of 37.44 hours with a brightness amplitude of 0.66 magnitude, indicative of an elongated shape (U=2).[7][lower-alpha 1] While not being a slow rotator, 1984 RA has a significantly longer period than most asteroids, which rotate once every 2 to 20 hours around their axis.

    Diameter and albedo

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, this asteroid measures 1.728 kilometers in diameter and its surface has an exceptionally high albedo of 0.78.[5][6] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.30 – a compromise value between the E- (0.40) and S-type (0.20) members of the Hungaria family and group, respectively – and calculates a diameter of 2.43 kilometers based on an absolute magnitude of 15.0.[3]

    Numbering and naming

    This minor planet was numbered by the Minor Planet Center on 26 July 2000 (M.P.C. 40991).[10] As of 2018, it has not been named.[1]

    Notes
    1. Lightcure plot of (15692) 1984 RA, by B. D. Warner at the Center for Solar System Studies – Palmer Divide Station (U82). Rotation period 37.44±0.05 hours. Observation from 8 Jul 2013 to 1 Aug 2013. Data points: 273. Quality code is 2. Summary figures at the LCDB
    gollark: ++remind 2w2d24h Ignore reminder ignorance.
    gollark: ++remind 2w6d Initiate Ħ sequence.
    gollark: ++remind 2w4d25h49m Message from the future: HEAVPOOT IS ABOUT TO BE VERY WRONG FOR SEVERAL DAYS.
    gollark: ++remind 2w5d25h54m gollark is NOT to be considered apioforms. Heavpoot IS to be considered apioforms.
    gollark: ++remind 2w5d25h51m Heavpoot is going to say MEAN THINGS about ME AND REMINDERS. They are FALSE.

    References
    1. "15692 (1984 RA)". Minor Planet Center. Retrieved 10 May 2018.
    2. "JPL Small-Body Database Browser: 15692 (1984 RA)" (2018-04-26 last obs.). Jet Propulsion Laboratory. Retrieved 10 May 2018.
    3. "LCDB Data for (15692)". Asteroid Lightcurve Database (LCDB). Retrieved 10 May 2018.
    4. "Asteroid (15692) 1984 RA – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 27 October 2019.
    5. 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.
    6. 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)
    7. Warner, Brian D. (January 2014). "Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2013 June- September". The Minor Planet Bulletin. 41 (1): 27–32. Bibcode:2014MPBu...41...27W. ISSN 1052-8091.
    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.
    9. 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.
    10. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 10 May 2018.

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