20936 Nemrut Dagi

20936 Nemrut Dagi, provisional designation 4835 T-1, is a stony asteroid from the innermost regions of the asteroid belt, approximately 3.5 kilometers in diameter. It was discovered on 13 May 1971, by Dutch astronomer couple Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by Dutch–American astronomer Tom Gehrels at the Palomar Observatory in California, United States.[2]

20936 Nemrut Dagi
Discovery [1]
Discovered byC. J. van Houten
I. van Houten-G.
T. Gehrels
Discovery sitePalomar Obs.
Discovery date13 May 1971
Designations
(20936) Nemrut Dagi
Named after
Nemrut Dağı
(volcano in Turkey)[2]
4835 T-1 · 1953 CP
1992 SR
main-belt · (inner)[1]
Hungaria [2] · Mars-crosser [3]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc45.97 yr (16,789 days)
Aphelion2.0420 AU
Perihelion1.6667 AU
1.8543 AU
Eccentricity0.1012
2.53 yr (922 days)
343.63°
Inclination18.604°
26.656°
324.48°
Physical characteristics
Dimensions3.21±0.50 km[4]
3.51±0.66 km[5]
3.57±0.19 km[6]
5.16 km (calculated)[3]
3.233±0.002 h (dated)[7]
3.2754±0.0005 h[7]
3.293±0.001 h[lower-alpha 1]
3.321±0.002 h (dated)[8]
5.697±0.002 h (dated)[9]
0.20 (assumed)[3]
0.31±0.11[4]
0.43±0.14[5]
0.460±0.078[6]
S [3]
13.70[6] · 13.8[1][3][5] · 14.46[4]

    Orbit and classification

    Nemrut Dagi as a member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. It orbits the Sun in the inner main-belt at a distance of 1.7–2.0 AU once every 2 years and 6 months (922 days). Its orbit has an eccentricity of 0.10 and an inclination of 19° with respect to the ecliptic.[1]

    Due to its perihelion of less than 1.668 AU, Nemrut Dagi is classified as a Mars-crosser by the Lightcurve Data Base,[3] while in JPL's data base, which requires a perihelion of less than 1.666  AU, the asteroid is simply an inner main-belt asteroid.

    The asteroid's observation arc begins 18 years prior to its official discovery observation, with its identification 1953 CP at Palomar Observatory in February 1953.[2]

    Survey designation

    The survey designation "T-1" stands for the first Palomar–Leiden Trojan survey, named after the fruitful collaboration of the Palomar and Leiden Observatory 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 asteroid discoveries.[10]

    Physical characteristics

    Lightcurves

    In December 2015, a rotational lightcurve of Nemrut Dagi was obtained by American astronomer Brian Warner at his CS3–Palmer Divide Station (U82) in California. Lightcurve analysis gave a well-defined rotation period of 3.2754 hours with a brightness variation of 0.08 magnitude (U=3), indicating that the body has a rather spheroidal shape.[7]

    The results supersede previous observations made by Warner and by Brian A. Skiff, which gave similar results (U=2).[8][9][lower-alpha 1]

    Diameter and albedo

    According to the surveys carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid has an exceptionally high albedo of 0.46 and a diameter of 3.6 kilometers,[6] while the Collaborative Asteroid Lightcurve Link assumed a standard albedo for stony asteroids of 0.20, and correspondingly, calculates a much larger diameter of 5.3 kilometers based on an absolute magnitude of 13.8.[3]

    Naming

    This minor planet was named after the a dormant volcano Nemrut (Nemrut Dağı) in Turkey. It is the most western volcano of a group of volcanoes near Lake Van in Eastern Anatolia. The volcano is named after King Nimrod who is said to have ruled this area in about 2100 BC.[2] The approved naming citation was published by the Minor Planet Center on 6 April 2012 (M.P.C. 79103).[11]

    Notes
    1. Skiff (2011) web: rotation period 3.293±0.001 hours with a brightness amplitude of 0.06 mag. Summary figures for (20936) Nemrut Dagi at Dagi Collaborative Asteroid Lightcurve Link (CALL)

    References
    1. "JPL Small-Body Database Browser: 20936 Nemrut Dagi (4835 T-1)" (2017-04-30 last obs.). Jet Propulsion Laboratory. Retrieved 4 July 2017.
    2. "20936 Nemrut Dagi (4835 T-1)". Minor Planet Center. Retrieved 26 January 2016.
    3. "LCDB Data for (20936) Nemrut Dagi". Asteroid Lightcurve Database (LCDB). Retrieved 26 January 2016.
    4. Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63. Retrieved 4 July 2017.
    5. Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117. Retrieved 4 July 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 26 January 2016.
    7. Warner, Brian D. (April 2016). "Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2015 October-December". The Minor Planet Bulletin. 43 (2): 137–140. Bibcode:2016MPBu...43..137W. ISSN 1052-8091. Retrieved 4 July 2017.
    8. Warner, Brian D. (July 2011). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2010 December- 2011 March". The Minor Planet Bulletin. 38 (3): 142–149. Bibcode:2011MPBu...38..142W. ISSN 1052-8091. Retrieved 26 January 2016.
    9. Warner, Brian D. (June 2008). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: September-December 2007". The Minor Planet Bulletin. 35 (2): 67–71. Bibcode:2008MPBu...35...67W. ISSN 1052-8091. Retrieved 26 January 2016.
    10. "Minor Planet Discoverers". Minor Planet Center. 23 March 2016. Retrieved 4 April 2016.
    11. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 4 July 2017.

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