2099 Öpik

2099 Öpik, provisional designation 1977 VB, is a dark and eccentric asteroid and Mars-crosser from the inner regions of the asteroid belt, approximately 5.1 kilometers in diameter.

2099 Öpik

Discovery [1]
Discovered by	E. F. Helin
Discovery site	Palomar Obs.
Discovery date	8 November 1977
Designations
MPC designation	(2099) Opik
Named after	Ernst Öpik (Estonian astronomer)[2]
Alternative designations	1977 VB · 1977 UL2
Minor planet category	Mars-crosser [1][3]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	60.26 yr (22,009 days)
Aphelion	3.1370 AU
Perihelion	1.4710 AU
Semi-major axis	2.3040 AU
Eccentricity	0.3616
Orbital period (sidereal)	3.50 yr (1,277 days)
Mean anomaly	148.76°
Mean motion	0° 16m 54.48s / day
Inclination	26.966°
Longitude of ascending node	218.84°
Argument of perihelion	159.18°
Earth MOID	0.4926 AU
Physical characteristics
Dimensions	5.12 km (calculated)[4] 5.17±1.35 km[5]
Synodic rotation period	6.4430±0.0002 h[6] 9.3 h[7]
Geometric albedo	0.05±0.06[5] 0.057 (assumed)[4]
Spectral type	S (Tholen)[1] Ch (SMASS)[1] C (CALL)[4] B–V = 0.690[1] U–B = 0.350[1]
Absolute magnitude (H)	15.18[1][4] · 15.22[5]

The asteroid was discovered on 8 November 1977, by American astronomer Eleanor Helin at the Palomar Observatory in California, and named after Estonian astronomer Ernst Öpik.^[3]

Orbit and classification

Öpik orbits the Sun in the inner main-belt at a distance of 1.5–3.1 AU once every 3 years and 6 months (1,277 days). Its orbit has an eccentricity of 0.36 and an inclination of 27° with respect to the ecliptic.^[1] The first used precovery was taken at the discovering observatory in 1970, extending the asteroid's observation arc by 7 years prior to its discovery.^[3]

Physical characteristics

Originally, the asteroid's spectral type was that of a bright S-type asteroid in the Tholen classification. More recently, it has been characterized as a dark Ch-type, a hydrated subtype of the carbonaceous C-type asteroids in the SMASS classification, which is in agreement with its low albedo (below).^[1]

Diameter and albedo

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Öpik measures 5.17 kilometers in diameter and its surface has an albedo of 0.05.^[5] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 5.12 kilometers with an absolute magnitude of 15.18.^[4]

Rotation period

In 2005, a photometric lightcurve analysis by several astronomers including Pierre Antonini, rendered a rotation period of 6.4430±0.0002 hours and with a brightness amplitude of 0.21 in magnitude (U=2),^[6] superseding the results of an observation from the 1990s that gave a longer period of 9.3 hours (U=2).^[7]

Naming

This minor planet was named after Estonian astronomer and astrophysicist, Ernst Öpik (1893–1985), who has influenced many fields of astronomy during his 60-year long career. He is noted for developing the discipline of statistical celestial mechanics and for methods to estimate the lifetimes of planet-crossing asteroids. In the early 1950s, he calculated the impact probability of Mars-crossing asteroids with Mars, and concluded that a search for impact craters on Mars would be a fruitful. Fourteen years later, Martian craters were discovered by Mariner 4.^[2] The official naming citation was published by the Minor Planet Center on 1 November 1978 (M.P.C. 4548).^[8]

References

1. "JPL Small-Body Database Browser: 2099 Opik (1977 VB)" (2017-03-05 last obs.). Jet Propulsion Laboratory. Retrieved 11 June 2017.
2. Schmadel, Lutz D. (2007). "(2099) Öpik". Dictionary of Minor Planet Names – (2099) Öpik. Springer Berlin Heidelberg. p. 170. doi:10.1007/978-3-540-29925-7_2100. ISBN 978-3-540-00238-3.
3. "2099 Opik (1977 VB)". Minor Planet Center. Retrieved 7 December 2016.
4. "LCDB Data for (2099) Öpik". Asteroid Lightcurve Database (LCDB). Retrieved 7 December 2016.
5. 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.
6. Behrend, Raoul. "Asteroids and comets rotation curves – (2099) Öpik". Geneva Observatory. Retrieved 7 December 2016.
7. Goretti, V. (December 2000). "CCD Photometry of the Mars-crosser Asteroid 2099 Opik". The Minor Planet Bulletin. 27: 46. Bibcode:2000MPBu...27...46G. Retrieved 27 April 2016.
8. Schmadel, Lutz D. (2009). "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7.