785 Zwetana is a minor planet orbiting the Sun that was discovered by Adam Massinger, an assistant at the Heidelberg Observatory, on March 30, 1914. It was named for the daughter of Kiril Popoff, a Bulgarian astronomer.[3] This asteroid is orbiting 2.57 AU from the Sun with an eccentricity (ovalness) of 0.21 and a period of 4.12 yr. The orbital plane is inclined by an angle of 12.8° to the plane of the ecliptic.[1]

785 Zwetana
Discovery
Discovered byAdam Massinger
Discovery siteHeidelberg
Discovery date30 March 1914
Designations
(785) Zwetana
1914 UN
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc95.43 yr (34854 d)
Aphelion3.1099 AU (465.23 Gm)
Perihelion2.0273 AU (303.28 Gm)
2.5686 AU (384.26 Gm)
Eccentricity0.21073
4.12 yr (1503.6 d)
268.20°
0° 14m 21.912s / day
Inclination12.769°
71.882°
131.607°
Physical characteristics
24.27±0.9 km
8.919 h[2]
8.8882 h (0.37034 d)[1]
0.1245±0.010
9.45

This asteroid spans a girth of ~48.5 km and it has a Tholen taxonomic class of M. Radar observations indicate that it is almost certainly metallic.[4] The near infrared spectra suggests the presence of spinel on the surface, which is indicative of calcium–aluminium-rich inclusions.[5] The best meteorite analog to the near infrared spectrum of this object is the enstatite chondrite, Abee.[6]

In 1990, the asteroid was observed from the European Southern Observatory, allowing a composite light curve to be produced that showed a rotation period of 8.919±0.004 h and a brightness variation of 0.13±0.01 in magnitude.[2] 2013 observations from the Palmer Divide Observatory found a rotation period of 8.885 hours with a magnitude amplitude of 0.18. This is consistent with other published results.[7]

References

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  1. ^ a b c Yeomans, Donald K., "785 Zwetana", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 5 May 2016.
  2. ^ a b Dotto, E.; et al. (June 1992), "M-type asteroids - Rotational properties of 16 objects", Astronomy and Astrophysics Supplement Series, vol. 95, no. 2, pp. 195–211, Bibcode:1992A&AS...95..195D.
  3. ^ Schmadel, Lutz D. (2013), Dictionary of Minor Planet Names, Springer Berlin Heidelberg, p. 117, ISBN 9783662066157.
  4. ^ Shepard, Michael K.; et al. (May 2008), "A radar survey of M- and X-class asteroids", Icarus, 195 (1): 184–205, Bibcode:2008Icar..195..184S, doi:10.1016/j.icarus.2007.11.032.
  5. ^ Hardersen, Paul S.; et al. (October 2007), "Nir Spectra And Interpretations For M-asteroids 369 Aeria And 785 Zwetana", Bulletin of the American Astronomical Society, 39: 478, Bibcode:2007DPS....39.3310H.
  6. ^ Ockert-Bell, M. E.; et al. (December 2010), "The composition of M-type asteroids: Synthesis of spectroscopic and radar observations", Icarus, 210 (2): 674–692, Bibcode:2010Icar..210..674O, doi:10.1016/j.icarus.2010.08.002.
  7. ^ Warner, Brian D. (July 2013), "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2013 January - March", The Minor Planet Bulletin, 40 (3): 137–145, Bibcode:2013MPBu...40..137W, ISSN 1052-8091, PMC 7268919, PMID 32494785.
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