4957 Brucemurray , provisional designation 1990 XJ , is a stony asteroid , classified as near-Earth object of the Amor group and as Mars-crosser , approximately 3 kilometers in diameter. It was discovered by American astronomer Eleanor Helin at the Palomar Observatory in California on 15 December 1990.[ 3] Bruce C. Murray .[ 2]
Orbit and classification
Brucemurray orbits the Sun at a distance of 1.2–1.9 AU once every 1 years and 12 months (715 days). Its orbit has an eccentricity of 0.22 and an inclination of 35° with respect to the ecliptic .[ 1]
The body's observation arc begins with a precovery taken at the Australian Siding Spring Observatory in March 1976, or more than 14 years prior to its official discovery observation.[ 3]
Close approaches
This deep Mars-crosser makes close approaches both to Earth and Mars. It has an Earth minimum orbital intersection distance of 0.4258 AU (63,700,000 km) which corresponds to 165.9 lunar distances . On 18 May 2033, the asteroid will also pass 0.0684 AU (10,230,000 km ) from Mars.[ 1]
Physical characteristics
In the SMASS classification , Brucemurray is a stony S-type asteroid .[ 1] [ 12]
Rotation period and axis
In the 1990s, two rotational lightcurves of Brucemurray were obtained from photometric observations by Czech astronomer Petr Pravec at Ondřejov Observatory . Lightcurve analysis gave a rotation period of 2.892 hours in both cases with a brightness variation of 0.28 and 0.36 magnitude , respectively (U=2/3 [ 8] [ 9]
In 2004, an international study modeled a lightcurve with a concurring period of 2.8922 hours and found a spin axis of (358.0°, −50.0°) in ecliptic coordinates (λ, β) (Q=3- [ 10]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of Wide-field Infrared Survey Explorer and the ExploreNEOs survey using the Spitzer Space Telescope , Brucemurray measures between 3.01 and 3.499 kilometers in diameter and its surface has an albedo between 0.132 and 0.18.[ 4] [ 5] [ 7] [ 11]
The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 3.11 kilometers based on an absolute magnitude of 14.9.[ 6]
Naming
This minor planet was named after American planetary scientist Bruce C. Murray (1931–2013), director of the Jet Propulsion Laboratory , co-founder of The Planetary Society and professor at California Institute of Technology . This asteroid which comes close both to Mars and Earth, is considered a particularly appropriate object for Murray, who had diligently championed a mission to Mars.[ 2]
The official naming citation was published by the Minor Planet Center on 29 November 1993 (M.P.C. 22829[ 13]
References
^ a b c d e f g h "JPL Small-Body Database Browser: 4957 Brucemurray (1990 XJ)" (2017-07-16 last obs.). Jet Propulsion Laboratory. Retrieved 15 September 2017 .^ a b c Schmadel, Lutz D. (2007). "(4957) Brucemurray". Dictionary of Minor Planet Names – (4957) Brucemurray . Springer Berlin Heidelberg . p. 427. doi :10.1007/978-3-540-29925-7_4836 . ISBN 978-3-540-00238-3 ^ a b c "4957 Brucemurray (1990 XJ)" . Minor Planet Center . Retrieved 15 September 2017 .^ a b c Harris, A. W.; Mommert, M.; Hora, J. L.; Mueller, M.; Trilling, D. E.; Bhattacharya, B.; et al. (March 2011). "ExploreNEOs. II. The Accuracy of the Warm Spitzer Near-Earth Object Survey" (PDF) . The Astronomical Journal . 141 (3): 10. Bibcode :2011AJ....141...75H . doi :10.1088/0004-6256/141/3/75 . S2CID 14208889 . ^ a b c d Trilling, D. E.; Mueller, M.; Hora, J. L.; Harris, A. W.; Bhattacharya, B.; Bottke, W. F.; et al. (September 2010). "ExploreNEOs. I. Description and First Results from the Warm Spitzer Near-Earth Object Survey" (PDF) . The Astronomical Journal . 140 (3): 770– 784. Bibcode :2010AJ....140..770T . doi :10.1088/0004-6256/140/3/770 . S2CID 3006566 . ^ a b c d e "LCDB Data for (4957) Brucemurray" . Asteroid Lightcurve Database (LCDB). Retrieved 15 September 2017 .^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Bauer, J.; Cutri, R. M.; McMillan, R. S.; et al. (November 2012). "Physical Parameters of Asteroids Estimated from the WISE 3-Band Data and NEOWISE Post-Cryogenic Survey". The Astrophysical Journal Letters . 760 (1): 6. arXiv :1210.0502 Bibcode :2012ApJ...760L..12M . doi :10.1088/2041-8205/760/1/L12 . S2CID 41459166 . ^ a b Pravec, Petr; Sarounová, Lenka; Wolf, Marek (December 1996). "Lightcurves of 7 Near-Earth Asteroids". Icarus . 124 (2): 471– 482. Bibcode :1996Icar..124..471P . doi :10.1006/icar.1996.0223 . ^ a b Pravec, Petr; Wolf, Marek; Sarounová, Lenka (November 1998). "Lightcurves of 26 Near-Earth Asteroids". Icarus . 136 (1): 124– 153. Bibcode :1998Icar..136..124P . doi :10.1006/icar.1998.5993 . ^ a b Kaasalainen, Mikko; Pravec, Petr; Krugly, Yurij N.; Sarounová, Lenka; Torppa, Johanna; Virtanen, Jenni; et al. (January 2004). "Photometry and models of eight near-Earth asteroids". Icarus . 167 (1): 178– 196. Bibcode :2004Icar..167..178K . doi :10.1016/j.icarus.2003.09.012 . ^ a b Thomas, C. A.; Trilling, D. E.; Emery, J. P.; Mueller, M.; Hora, J. L.; Benner, L. A. M.; et al. (September 2011). "ExploreNEOs. V. Average Albedo by Taxonomic Complex in the Near-Earth Asteroid Population" . The Astronomical Journal . 142 (3): 12. Bibcode :2011AJ....142...85T . doi :10.1088/0004-6256/142/3/85 ^ a b c d e Dandy, C. L.; Fitzsimmons, A.; Collander-Brown, S. J. (June 2003). "Optical colors of 56 near-Earth objects: trends with size and orbit". Icarus . 163 (2): 363– 373. Bibcode :2003Icar..163..363D . doi :10.1016/S0019-1035(03)00087-3 . ^ "MPC/MPO/MPS Archive" . Minor Planet Center . Retrieved 15 September 2017 .
External links
