Astronomy:1995 Hajek

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1995 Hajek
Discovery[1]
Discovered byL. Kohoutek
Discovery siteBergedorf Obs.
Discovery date26 October 1971
Designations
(1995) Hajek
Named afterTadeáš Hájek (astronomer)[2]
1971 UP1 · 1941 EA
Minor planet categorymain-belt · (middle)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc76.21 yr (27,836 days)
|{{{apsis}}}|helion}}2.6677 AU
|{{{apsis}}}|helion}}2.3911 AU
2.5294 AU
Eccentricity0.0547
Orbital period4.02 yr (1,469 days)
Mean anomaly6.1573°
Mean motion0° 14m 42s / day
Inclination10.825°
Longitude of ascending node47.232°
134.65°
Physical characteristics
Dimensions6.50 km (calculated)[3]
12.683±0.288 km[4][5]
14.45±2.58 km[6]
15.29±1.04 km[7]
Rotation period10 h[8]
Geometric albedo0.040±0.025[6][5]
0.063±0.010[7]
0.0833±0.0249[4]
0.20 (assumed)[3]
P[4] · X[3][9][10]
Absolute magnitude (H)12.80[4][7] · 13.06±0.33[9] · 13.3[1][3][6]


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.[11] It was named after Renaissance astronomer Tadeáš Hájek.[2]

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.[1] 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 ({{{1}}}).[8]

Hajek has the spectral properties of a metallic X-type asteroid.[3][9][10] It is also classified as a dark P-type asteroid by NASA's Wide-field Infrared Survey Explorer (WISE).[4]

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.[4][6][7] 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.[3] 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.[12]

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.[2] The official naming citation was published by the Minor Planet Center on 1 April 1978 (M.P.C. 4358).[13]

References

  1. 1.0 1.1 1.2 1.3 "JPL Small-Body Database Browser: 1995 Hajek (1971 UP1)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001995. 
  2. 2.0 2.1 2.2 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. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 "LCDB Data for (1995) Hajek". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=1995%7CHajek. 
  4. 4.0 4.1 4.2 4.3 4.4 4.5 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. doi:10.1088/0004-637X/741/2/90. Bibcode2011ApJ...741...90M. 
  5. 5.0 5.1 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. doi:10.1088/0004-637X/741/2/68. Bibcode2011ApJ...741...68M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...68M. Retrieved 8 December 2016. 
  6. 6.0 6.1 6.2 6.3 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. doi:10.1088/2041-8205/759/1/L8. Bibcode2012ApJ...759L...8M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012ApJ...759L...8M. Retrieved 8 December 2016. 
  7. 7.0 7.1 7.2 7.3 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. doi:10.1093/pasj/63.5.1117. Bibcode2011PASJ...63.1117U.  (online, AcuA catalog p. 153)
  8. 8.0 8.1 Behrend, Raoul. "Asteroids and comets rotation curves – (1995) Hajek". Geneva Observatory. http://obswww.unige.ch/~behrend/page4cou.html#001995. 
  9. 9.0 9.1 9.2 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. doi:10.1016/j.icarus.2015.08.007. Bibcode2015Icar..261...34V. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V. Retrieved 8 December 2016. 
  10. 10.0 10.1 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. doi:10.1006/icar.1995.1075. ISSN 0019-1035. Bibcode1995Icar..115....1X. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=1995Icar..115....1X. Retrieved 17 December 2015. 
  11. "1995 Hajek (1971 UP1)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=1995. 
  12. "Asteroid Size Estimator". CNEOS NASA/JPL. https://cneos.jpl.nasa.gov/tools/ast_size_est.html. 
  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. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7. Bibcode2009dmpn.book.....S. https://archive.org/details/dictionaryminorp2008schm. 

External links