| Discovery[1] | |
|---|---|
| Discovered by | C. J. van Houten I. van Houten-G. T. Gehrels |
| Discovery site | Palomar Obs. |
| Discovery date | 13 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 arc | 50.12yr (18,308 d) |
| Aphelion | 2.0419AU |
| Perihelion | 1.6671 AU |
| 1.8545 AU | |
| Eccentricity | 0.1011 |
| 2.53 yr (922 d) | |
| 168.55° | |
| 0° 23m 25.08s / day | |
| Inclination | 18.599° |
| 26.629° | |
| 324.45° | |
| Physical characteristics | |
| 3.2754±0.0005 h[6][7] | |
| E/S[7] | |
| 14.02[1][2] | |
20936 Nemrut Dagi (provisional designation4835 T-1) is a stonyHungaria asteroid and Mars-grazer from the innermost regions of theasteroid belt, approximately 3.5 kilometers (2.2 miles) in diameter. It was discovered on 13 May 1971, by Dutch astronomer coupleIngrid andCornelis van Houten atLeiden, on photographic plates taken by Dutch–American astronomerTom Gehrels atPalomar Observatory in California, United States. The asteroid has arotation period of 3.28 hours, a likely spheroidal shape, and a highalbedo typically seen among theenstatite-richE-type asteroids. In 2012, it was named after the a dormant volcanoNemrut (Nemrut Dağı) in Turkey.[1]
Nemrut Dagi belongs to the dynamical group ofHungaria asteroids,[1] which form the innermost dense concentration of asteroids in theSolar System. It orbits the Sun in theinner 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 aneccentricity of 0.10 and aninclination of 19° with respect to theecliptic.[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 theJPL's data base, where it would be labelled aMars-crosser if it had a perihelion of 1.666 AU or less.[2] The asteroid'sobservation arc begins with its observation as1953 CP at Palomar Observatory in February 1953, or 18 years prior to its official discovery in 1971.[1]
Upon discovery, thisminor planet was designated4835 T-1. Thesurvey designation means that it was the 4835th object discovered in the "T-1" series, which stands for the firstPalomar–Leiden Trojan survey, named after the fruitful collaboration of the Palomar andLeiden Observatory in the 1960s and 1970s. Gehrels used Palomar'sSamuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped thephotographic plates to Ingrid and Cornelis van Houten at Leiden Observatory whereastrometry was carried out. The trio are credited withseveral thousand asteroid discoveries.[8]
It was named after the dormant volcanoNemrut (Nemrut Dağı) in Turkey. It is the most western volcano of a group of volcanoes nearLake 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 astronomerJoachim Schubart,[1] and its officialnaming citation was published by theMinor Planet Center on 6 April 2012 (M.P.C. 79103).[9]
In December 2015, a rotationallightcurve of Nemrut Dagi was obtained by American astronomerBrian Warner at his CS3–Palmer Divide Station (U82) in California. Lightcurve analysis gave a well-definedrotation period of3.2754±0.0005 hours with a low brightness variation of0.08±0.01magnitude (U=3), indicating that the body has a rather spheroidal shape.[6]
This result supersedes previous observations. Warner obtained similar periods of3.233±0.002 and an amplitude of0.05±0.01 (November 2007, revised),[6]3.321±0.002 hours and0.15±0.02 (February 2011),[10] and5.697±0.002 hours and0.15±0.02 (November 2007),[11] with a quality code ofU=2, 2 and 0, respectively.[7] The asteroid was also observed by American astronomerBrian A. Skiff during the Near-Earth Asteroid Photometric Survey (NEAPS) at Lowell Observatory, who obtained a period of3.233±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 of3.283±0.007,3.285±0.004, and3.274±0.003 (U=2+,2+,2+).[12] In May 2019, observations byRobert Stephens at CS3 (U81) determined a period of3.328±0.002 (U=2).[13]: 453
According to the surveys carried out by NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission, the asteroid has a mean-diameter of3.21±0.50 km,3.51±0.66 km, and3.57±0.19 km with an exceptionally highalbedo of0.31±0.11,0.43±0.14, and0.460±0.078, respectively.[3][4][5][14] A high albedo of 0.30 or more is typically seen among the brightE-type asteroids that are thought to be composed ofenstatite, a mineral which is rich inMagnesium sulfite (MgS03). TheCollaborative Asteroid Lightcurve Link assumed a standard albedo for a commonS-type asteroid of 0.20, and calculates a larger diameter of 5.3 kilometers based on anabsolute magnitude of 13.8.[7]
