Discovery [1] | |
---|---|
Discovered by | S. Singer-Brewster |
Discovery site | Palomar Obs. |
Discovery date | 24 August 1987 |
Designations | |
(15700) 1987 QD | |
1987 QD · 2000 JD1 | |
Mars-crosser
[1]
[2] binary [3] [4] [5] | |
Orbital characteristics [2] | |
Epoch 23 March 2018 ( JD 2458200.5) | |
Uncertainty parameter 0 | |
Observation arc | 63.65 yr (23,249 d) |
Aphelion | 2.9047 AU |
Perihelion | 1.5136 AU |
2.2092 AU | |
Eccentricity | 0.3148 |
3.28 yr (1,199 d) | |
132.51 ° | |
0° 18m 0.72s / day | |
Inclination | 26.788° |
175.47° | |
119.47° | |
Known satellites | 1 (strong candidate) [3] [6] |
Earth MOID | 0.6219 AU (242 LD) |
Physical characteristics | |
Mean diameter | 2.95±0.29
km
[7] 3.04 km (derived) [4] |
3.0586±0.0001 h [6] [a] | |
0.20 (assumed)
[4] 0.268±0.054 [7] | |
X (
Pan-STARRS)
[4]
[8] X ( SDSS-MOC) [9] S [4] [10] | |
14.50±0.07 (R)
[a] 14.70 [1] [2] [7] 14.99±0.086 [4] [11] | |
(15700) 1987 QD ( provisional designation 1987 QD) is a Mars-crossing asteroid and a binary candidate from inside the innermost region of the asteroid belt, approximately 3 kilometers (1.9 miles) in diameter. It was discovered on 24 August 1987, by American astronomer Stephen Singer-Brewster at the Palomar Observatory in California. [1] The likely spherical X-type asteroid has a rotation period of 3.1 hours. The suspected presence of a kilometer-sized minor-planet moon was announced in November 2000. [3]
1987 QD is a Mars-crossing asteroid, a member of the dynamically unstable group, located between the main belt and near-Earth populations, and crossing the orbit of Mars at 1.666 AU. It orbits the Sun inside the innermost region of the asteroid belt at a distance 1.5–2.9 AU once every 3 years and 3 months (1,199 days; semi-major axis of 2.21 AU). Its orbit has an eccentricity of 0.31 and an inclination of 27 ° with respect to the ecliptic. [2]
The body's observation arc begins with a precovery published by the Digitized Sky Survey and taken at Palomar in May 1954, more than 33 years prior to its official discovery observation. [1] It will pass 6,352,000 km (0.04246 AU) from the main-belt asteroid 7 Iris on 3 September 2173. [2]
This minor planet was numbered by the Minor Planet Center on 26 July 2000 ( M.P.C. 40991). [12] As of 2018, it has not been named. [1]
In the SDSS-based taxonomy and according to the survey conducted by Pan-STARRS, 1987 QD is an X-type asteroid. [4] [8] [9] It has also been classified as a common, stony S-type asteroid. [4] [10]
In September 2010, a first rotational lightcurve of 1987 QD was obtained from photometric observations by Brian Skiff. Lightcurve analysis gave a rotation period of 3.068 hours and a brightness variation of 0.07 magnitude ( U=3-). [4] [b] Within less than two weeks, follow-up observations by a large international collaboration of astronomers determined a refined period of 3.0586±0.0001 hours with a low amplitude of 0.07 magnitude, indicating that the body has a spherical shape ( U=3). [6] [a] An alternative observation that gave a tentative period 9.709 hours received a poor quality rating ( U=1). [4] [13]
The photometric observations during September and October 2010 revealed that 1987 QD is a candidate for a synchronous binary asteroid with a minor-planet moon orbiting it every 50.3±0.5 hours at an estimated average distance of 14 km. [3] The findings were announced on 6 November 2009. [6] The lightcurve indicated mutual occultation events, however, a conclusive solution for the orbit period was not obtained. [c] The Johnston's archive estimates a diameter of 1.23 kilometer for the satellite, or 31% the size of its primary. [3]
The international collaboration included Richard Durkee at the Shed of Science Observatory ( H39), Petr Pravec, Kamil Hornoch and Peter Kušnirák at Ondřejov Observatory, Donald Pray at Carbuncle Hill Observatory ( 912), David Higgins at Canberra ( E14), Jozef Világi and Štefan Gajdoš at Modra Observatory, Judit Györgyey Ries at McDonald Observatory and Julian Oey at Leura Observatory ( E17), as well as astronomers at the Kharkiv Kharkov ( 101), Simeiz and Skalnate Pleso observatories. [6]
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, 1987 QD measures 2.95 kilometers in diameter and its surface has an albedo of 0.268, [7] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a stony asteroid of 0.20 and derives a diameter of 3.04 kilometers based on an absolute magnitude of 14.99. [4]