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20936 Nemrut Dagi

20936 Nemrut Dagi (provisional designation 4835 T-1) is a stony Hungaria asteroid and Mars-grazer from the innermost regions of the asteroid belt, approximately 3.5 kilometers (2.2 miles) 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 Palomar Observatory in California, United States. The asteroid has a rotation period of 3.28 hours, a likely spheroidal shape, and a high albedo typically seen among the enstatite-rich E-type asteroids. In 2012, it was named after the a dormant volcano Nemrut (Nemrut Dağı) in Turkey.[1]

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)[1]
4835 T-1 · 1953 CP
1992 SR
main-belt · (inner)[2]
Hungaria [1]
Orbital characteristics[2]
Epoch 1 July 2021 (JD 2459396.5)
Uncertainty parameter 0
Observation arc50.12 yr (18,308 d)
Aphelion2.0419 AU
Perihelion1.6671 AU
1.8545 AU
Eccentricity0.1011
2.53 yr (922 d)
168.55°
0° 23m 25.08s / day
Inclination18.599°
26.629°
324.45°
Physical characteristics
  • 3.21±0.50 km[3]
  • 3.51±0.66 km[4]
  • 3.567±0.189 km[5]
3.2754±0.0005 h[6][7]
E/S [7]
14.02[1][2]

Orbit and classification

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Nemrut Dagi belongs to the dynamical group of Hungaria asteroids,[1] 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; semi-major axis of 1.85 AU). Its orbit has an eccentricity of 0.10 and an inclination of 19° with respect to the ecliptic.[2] Nemrut Dagi is also an outer Mars-grazer, as its orbit has a perihelion (1.667 AU) slightly below the aphelion of Mars (1.67 AU), not crossing the Red Plant's osculating orbit. It is classified as an "inner main-belt asteroid" in the JPL's data base, where it would be labelled a Mars-crosser if it had a perihelion of 1.666 AU or less.[2] The asteroid's observation arc begins with its observation as 1953 CP at Palomar Observatory in February 1953, or 18 years prior to its official discovery in 1971.[1]

Designation

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Survey designation

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Upon discovery, this minor planet was designated 4835 T-1. The survey designation means that it was the 4835th object discovered in the "T-1" series, which 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 several thousand asteroid discoveries.[8]

Naming

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It was named after the 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. The asteroid's name was proposed by German astronomer Joachim Schubart,[1] and its official naming citation was published by the Minor Planet Center on 6 April 2012 (M.P.C. 79103).[9]

Physical characteristics

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Lightcurves

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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±0.0005 hours with a low brightness variation of 0.08±0.01 magnitude (U=3), indicating that the body has a rather spheroidal shape.[6]

This result supersedes previous observations. Warner obtained similar periods of 3.233±0.002 and an amplitude of 0.05±0.01 (November 2007, revised),[6] 3.321±0.002 hours and 0.15±0.02 (February 2011),[10] and 5.697±0.002 hours and 0.15±0.02 (November 2007),[11] with a quality code of U=2, 2 and 0, respectively.[7] The asteroid was also observed by American astronomer Brian A. Skiff during the Near-Earth Asteroid Photometric Survey (NEAPS) at Lowell Observatory, who obtained a period of 3.233±0.002 in February 2011, which he directly reported to the LCBD (U=2).[a] Additional observations by NEAPS were published in 2019, and gave a concurring period of 3.283±0.007, 3.285±0.004, and 3.274±0.003 (U=2+,2+,2+).[12] In May 2019, observations by Robert Stephens at CS3 (U81) determined a period of 3.328±0.002 (U=2).[13]: 453 

Diameter and albedo

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According to the surveys carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid has a mean-diameter of 3.21±0.50 km, 3.51±0.66 km, and 3.57±0.19 km with an exceptionally high albedo of 0.31±0.11, 0.43±0.14, and 0.460±0.078, respectively.[3][4][5][14] A high albedo of 0.30 or more is typically seen among the bright E-type asteroids that are thought to be composed of enstatite, a mineral which is rich in Magnesium sulfite (MgS03). The Collaborative Asteroid Lightcurve Link assumed a standard albedo for a common S-type asteroid of 0.20, and calculates a larger diameter of 5.3 kilometers based on an absolute magnitude of 13.8.[7]

Notes

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  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

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  1. ^ a b c d e f g h "20936 Nemrut Dagi (4835 T-1)". Minor Planet Center. Retrieved 30 August 2021.
  2. ^ a b c d e "JPL Small-Body Database Browser: 20936 Nemrut Dagi (4835 T-1)" (2021-06-27 last obs.). Jet Propulsion Laboratory. Retrieved 30 August 2021.
  3. ^ a b c 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.
  4. ^ a b c 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. S2CID 9341381.
  5. ^ a b c 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. S2CID 46350317.
  6. ^ a b c Warner, Brian D. (April 2016). "Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2015 October-December" (PDF). The Minor Planet Bulletin. 43 (2): 137–140. Bibcode:2016MPBu...43..137W. ISSN 1052-8091. PMC 7243998. PMID 32455371. Retrieved 30 August 2021. Lightcurve plot
  7. ^ a b c d "LCDB Data for (20936) Nemrut Dagi". Asteroid Lightcurve Database (LCDB). Retrieved 26 January 2016.
  8. ^ "Minor Planet Discoverers". Minor Planet Center. 23 March 2016. Retrieved 4 April 2016.
  9. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 4 July 2017.
  10. ^ Warner, Brian D. (July 2011). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2010 December- 2011 March" (PDF). The Minor Planet Bulletin. 38 (3): 142–149. Bibcode:2011MPBu...38..142W. ISSN 1052-8091. Retrieved 30 August 2021.
  11. ^ Warner, Brian D. (June 2008). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: September–December 2007" (PDF). The Minor Planet Bulletin. 35 (2): 67–71. Bibcode:2008MPBu...35...67W. ISSN 1052-8091. Retrieved 30 August 2021.
  12. ^ Skiff, Brian A.; McLelland, Kyle P.; Sanborn, Jason J.; Pravec, Petr; Koehn, Bruce W. (October 2019). "Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS): Paper 4". Minor Planet Bulletin. 46 (4): 458–503. Bibcode:2019MPBu...46..458S. ISSN 1052-8091.
  13. ^ Stephens, Robert D.; Warner, Brian D. (October 2019). "Main-belt Asteroids Observed from CS3: 2019 April to June" (PDF). Minor Planet Bulletin. 46 (4): 449–456. Bibcode:2019MPBu...46..449S. ISSN 1052-8091. Archived from the original (PDF) on 8 June 2021. Retrieved 30 August 2021. Lightcurve plot
  14. ^ "Asteroid 20936 Nemrut Dagi – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 30 August 2021.
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