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1995 Hajek, provisional designation 1971 UP₁, is a metallic asteroid from the middle region of the asteroid belt, approximately 13 kilometers in diameter.

It was discovered on 26 October 1971, by Czech astronomer Luboš Kohoutek at the Bergedorf Observatory in Hamburg, Germany. It was named after Renaissance astronomer Tadeáš Hájek.

Orbit and classification

Hajek orbits the Sun in the middle main-belt at a distance of 2.4–2.7 AU once every 4.02 years (1,469 days). Its orbit has an eccentricity of 0.05 and an inclination of 11° with respect to the ecliptic. It was first identified as 1941 EA at Heidelberg in 1941. The body's used observation was a precovery taken at Palomar Observatory in 1951, extending its observation arc by 20 years prior to the official discovery observation at Heidelberg.

Physical characteristics

A first rotational lightcurve of Hajek was obtained by French amateur astronomers Alain Klotz, Marc Rieugné, and Pierre Thierry in October 2013. It gave a provisional rotation period of 10 hours with a brightness variation of 0.10 magnitude (U=1+).

Hajek has the spectral properties of a metallic X-type asteroid. It is also classified as a dark P-type asteroid by NASA's Wide-field Infrared Survey Explorer (WISE).

According to the surveys carried out by the Japanese Akari satellite and WISE space-telescope with its subsequent NEOWISE mission, Hajek measures between 12.7 and 15.3 kilometers in diameter and its surface has an albedo of 0.040 and 0.083. The Collaborative Asteroid Lightcurve Link strongly disagrees with the space-based observations and assumes a standard albedo for stony asteroids of 0.200 and calculates a much smaller diameter of 6.5 kilometers. These contrasting albedo and diameter figures closely correspond to a generic magnitude-to-diameter conversion, where, for an absolute magnitude of 13.3, the body's diameter is in the range of 6 to 14 kilometers, based on an albedo between 0.05 and 0.25.

Naming

This minor planet was named after the Bohemian astronomer Tadeáš Hájek (1525–1600), better known by his Latinized name, Thaddaeus Hagecius. He was one of the founders of modern stellar and cometary astronomy, who studied the Great Comet of 1577 and the supernova SN 1572, also known as Tycho's Nova. The lunar crater Hagecius is also named in his honour. The official naming citation was published by the Minor Planet Center on 1 April 1978 (M.P.C. 4358).

References

1. ^ "JPL Small-Body Database Browser: 1995 Hajek (1971 UP1)" (2017-06-04 last obs.). Jet Propulsion Laboratory. Archived from the original on 20 December 2016. Retrieved 1 July 2017.
2. ^ Schmadel, Lutz D. (2007). "(1995) Hajek". Dictionary of Minor Planet Names – (1995) Hajek. Springer Berlin Heidelberg. p. 161. doi:10.1007/978-3-540-29925-7_1996. ISBN 978-3-540-00238-3.
3. ^ "LCDB Data for (1995) Hajek". Asteroid Lightcurve Database (LCDB). Retrieved 8 December 2016.
4. ^ Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. S2CID 35447010.
5. ^ Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. S2CID 118745497. Retrieved 8 December 2016.
6. ^ Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. S2CID 46350317. Retrieved 8 December 2016.
7. ^ Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)
8. ^ Behrend, Raoul. "Asteroids and comets rotation curves – (1995) Hajek". Geneva Observatory. Retrieved 8 December 2016.
9. ^ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 – Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. S2CID 53493339. Retrieved 8 December 2016.
10. ^ Xu, Shui; Binzel, Richard P.; Burbine, Thomas H.; Bus, Schelte J. (May 1995). "Small main-belt asteroid spectroscopic survey: Initial results". Icarus. 115 (1): 1–35. Bibcode:1995Icar..115....1X. doi:10.1006/icar.1995.1075. ISSN 0019-1035. Retrieved 17 December 2015.
11. "1995 Hajek (1971 UP1)". Minor Planet Center. Retrieved 8 December 2016.
12. "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 21 October 2019.
13. 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. Bibcode:2009dmpn.book.....S. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7.

External links

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 1995 Hajek at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 1995 Hajek at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• Background asteroids
• Discoveries by Luboš Kohoutek
• Named minor planets
• X-type asteroids
• Astronomical objects discovered in 1971