(450894) 2008 BT18
| Discovery [1] | |
|---|---|
| Discovered by | LINEAR |
| Discovery site | Lincoln Lab's ETS |
| Discovery date | 31 January 2008 |
| Designations | |
| MPC designation | (450894) 2008 BT18 |
| 2008 BT18 | |
| Apollo · NEO · PHA [1][2] | |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 60.59 yr (22,132 days) |
| Aphelion | 3.5401 AU |
| Perihelion | 0.9030 AU |
| 2.2216 AU | |
| Eccentricity | 0.5935 |
| 3.31 yr (1,209 days) | |
| 284.48° | |
| 0° 17m 51.72s / day | |
| Inclination | 8.1338° |
| 107.67° | |
| 139.28° | |
| Known satellites | 1 [a][b] |
| Earth MOID | 0.0108 AU · 4.2 LD |
| Physical characteristics | |
| Dimensions | 0.6 km[a] 0.630 km [3] 0.650 km (calculated)[4] |
| 2.726±0.007 h[c] | |
| 0.20 (assumed)[4] | |
| S [4] · V [c] | |
| 18.3[1][4] | |
(450894) 2008 BT18 is an eccentric, sub-kilometer sized binary[b] asteroid of the Apollo group, classified as near-Earth object and potentially hazardous asteroid.
It was discovered on 31 January 2008, by the LINEAR program at Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, United States.[2] The primary and its minor-planet moon measure approximately 600 and 200 meters, respectively.
Contents
Orbit and classification[edit]
2008 BT18 orbits the Sun at a distance of 0.9–3.5 AU once every 3 years and 4 months (1,209 days). Its orbit has an eccentricity of 0.59 and an inclination of 8° with respect to the ecliptic.[1] Published by the Digitized Sky Survey (DSS), a first precovery was taken at Palomar Observatory in 1953, extending the asteroid's observation arc by 55 years prior to its discovery.[2]
The asteroid has a low Earth minimum orbit intersection distance of 0.0108 AU (1,620,000 km) which corresponds to 4.2 lunar distances (LD). On 14 July 2008, it transited Earth within 0.015 AU (5.9 LD).[1]
Physical characteristics[edit]
The S-type asteroid is also classified as a V-type by NASA's Infrared Telescope Facility, IRTF.[c]
Rotation period[edit]
A rotational lightcurve for this body was obtained from photometric observations made by astronomer Alberto Betzler at Salvador, Brazil, in July 2008. The fragmentary light-curve gave a rotation period of 2.726±0.007 hours with a brightness variation of 0.04 in magnitude (U=1).[c]
Binary system[edit]
On 6 and 7 July 2008, research conducted using the Arecibo Observatory produced evidence that this is a binary system with an asteroid moon.[5] The secondary component has a diameter of at least 200 meters, about 33% the size of and up to 1.5 kilometers apart from its primary.[a][b] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 650 meters, based on an absolute magnitude of 18.3.[4]
Naming[edit]
As of 2017, this minor planet remains unnamed.[2]
Notes[edit]
- ^ a b c Benner (2008) web: diameter 0.6 kilometers. Central Bureau Electronic Telegrams, No. 1450, #1 (2008). Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (450894)
- ^ a b c Central Bureau for Astronomical Telegrams, No. 1450, from 29 July 2008:
Arecibo (2380-MHz, 12.6-cm) and Goldstone (8560-MHz, 3.5-cm) radar observations during July 6, 7, and 11 reveal that minor planet 2008 BT_18 (cf. MPECs 2008-C03, 2008-H06; MPO 140193) is a binary system. Preliminary estimates for the component diameters are about 0.6 km and > 200 m. The maximum distance between the components on July 11 is at least 1.5 km.
Reported by: L. A. M. Benner, Jet Propulsion Laboratory (JPL), California Institute of Technology (CIT); M. C. Nolan and E. S. Howell, Arecibo Observatory, National Astronomy and Ionosphere Center; C. Magri, University of Maine at Farmington; J. D. Giorgini, S. J. Ostro, and M. Brozovic, JPL/CIT; M. W. Busch, CIT; J. L. Margot and P. A. Taylor, Cornell University; M. K. Shepard, Bloomsburg University; L. M. Carter, Smithsonian Institution; and T. M. Becker, Lehigh University CBET No. 1450 - ^ a b c d Betzler (2009) web: rotation period 2.726±0.007 hours with a brightness amplitude of 0.04 mag. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (450894) and Observations of V-type Binary Near-Earth Asteroids 2006 VV2 and 2008 BT18
References[edit]
- ^ a b c d e f "JPL Small-Body Database Browser: 450894 (2008 BT18)" (2015-10-17 last obs.). Jet Propulsion Laboratory. Retrieved 2 June 2017.
- ^ a b c d "450894 (2008 BT18)". Minor Planet Center. Retrieved 21 May 2016.
- ^ Johnston, Wm. Robert (September 20, 2014). "2008 BT18". Johnston's Archive. Archived from the original on 8 October 2014. Retrieved 14 November 2015.
- ^ a b c d e "LCDB Data for (450894)". Asteroid Lightcurve Database (LCDB). Retrieved 21 May 2016.
- ^ "2008 BT18 Goldstone Radar Observations Planning". NASA Jet Propulsion Laboratory. Retrieved 2008-08-01.[permanent dead link]
External links[edit]
- Asteroids with Satellites, Robert Johnston, johnstonsarchive.net
- Asteroid Lightcurve Database (LCDB), query form (info)
- Dictionary of Minor Planet Names, Google books
- Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
- Discovery Circumstances: Numbered Minor Planets (450001)-(455000) – Minor Planet Center
- (450894) 2008 BT18 at the JPL Small-Body Database
