20936 Nemrut Dagi

20936 Nemrut Dagi
Discovery [1]
Discovered by PLS
C. J. van Houten
I. van Houten
Tom Gehrels
Discovery site Palomar Obs.
Discovery date 13 May 1971
Designations
MPC designation 20936 Nemrut Dagi
Named after
 Nemrut Dağı
(volcano)[2]
4835 T-1 · 1953 CP
1992 SR
main-belt (inner)[1]
Hungaria[2]
Mars-crosser[3]
Orbital characteristics [1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc 44.85 yr (16,382 days)
Aphelion 2.0419 AU
Perihelion 1.6666 AU
1.8543 AU
Eccentricity 0.1012
2.53 yr (922 days)
109.71°
Inclination 18.600°
26.664°
324.22°
Earth MOID 0.6839 AU
Physical characteristics
Dimensions 3.57±0.19 km[4]
5.16 km (calculated)[3]
3.2754±0.0005 h[lower-alpha 1]
3.321±0.002 h[5]
5.697±0.002 h[6]
3.233±0.002[lower-alpha 1]
3.293±0.001 h[lower-alpha 2]
0.460±0.078[4]
0.20 (assumed)[3]
S [3]
13.8[1][3]
13.70[4]

    20936 Nemrut Dagi, provisional designation 4835 T-1, is a stony asteroid from the innermost regions of the asteroid belt, roughly 4 to 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 U.S. Palomar Observatory in California.[2]

    The asteroid orbits the Sun 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 plane of the ecliptic.[1] The Collaborative Asteroid Lightcurve Link (CALL) also classifies the S-type asteroid as a Mars-crosser, due to a perihelion of less than 1.668 AU,[3] while German astronomer Joachim Schubart, who suggested the body's name, described it as a member of the Hungaria family, as its semi-major axis lies in between 1.78 and 2.0 AU. Although the two different classifications are not mutually exclusive, other orbital parameters, such as a period of 2.5 years, an eccentricity of less than 0.16, and an inclination between 16° and 34°, are typical for Hungaria asteroids.

    In December 2015, a photometric light-curve analysis by astronomer Brian Warner the U.S. Palmer Divide Observatory (PDO), Colorado, rendered the first well-defined rotation period of 3.2754±0.0005 hours with a brightness amplitude of 0.08 in magnitude (U=3). Previous observations at the PDO and by astronomer Brian A. Skiff rendered similar periods between 3.23 and 3.29 hours with an amplitude in the range of 0.05 to 0.15 (U=2).[5][lower-alpha 1][lower-alpha 2]

    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,[4] 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.[3]

    The special 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 Cornelis van Houten and Ingrid van Houten-Groeneveld at Leiden Observatory where astrometry was carried out. The trio of astronomers are credited with the discovery of 4,619 minor planets.[7]

    The minor planet is 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]

    References

    1. 1 2 3 Warner (2016): rotation period 3.2754±0.0005 hours with a brightness amplitude of 0.08 mag. U=3. Another observation from 2007 gave a period of 3.233±0.002 with a variation of 0.05 in mag (U=2). Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (20936) Nemrut Dagi
    2. 1 2 Skiff (2011) web: rotation period 3.293±0.001 hours with a brightness amplitude of 0.06 mag. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (20936) Nemrut Dagi
    1. 1 2 3 4 5 "JPL Small-Body Database Browser: 20936 Nemrut Dagi (4835 T-1)" (2016-03-19 last obs.). Jet Propulsion Laboratory. Retrieved April 2016.
    2. 1 2 3 4 "20936 Nemrut Dagi (4835 T-1)". Minor Planet Center. Retrieved January 2016.
    3. 1 2 3 4 5 6 7 "LCDB Data for (20936) Nemrut Dagi". Asteroid Lightcurve Database (LCDB). Retrieved January 2016.
    4. 1 2 3 4 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 January 2016.
    5. 1 2 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 January 2016.
    6. ↑ 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 January 2016.
    7. ↑ "Minor Planet Discoverers". Minor Planet Center. 23 March 2016. Retrieved April 2016.

    External links

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