Astronomy:4606 Saheki
.png) Lightcurve-based 3D-model of Saheki | |
| Discovery [1] | |
|---|---|
| Discovered by | T. Seki |
| Discovery site | Geisei Obs. |
| Discovery date | 27 October 1987 |
| Designations | |
| (4606) Saheki | |
| Named after | Tsuneo Saheki (astronomer)[2] |
| 1987 UM1 · 1972 GA1 1977 TJ7 · 1977 VF2 1982 FH4 | |
| Minor planet category | main-belt · Flora [3] |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 63.81 yr (23,305 days) |
| |{{{apsis}}}|helion}} | 2.4805 AU |
| |{{{apsis}}}|helion}} | 2.0231 AU |
| 2.2518 AU | |
| Eccentricity | 0.1016 |
| Orbital period | 3.38 yr (1,234 days) |
| Mean anomaly | 202.74° |
| Mean motion | 0° 17m 30.12s / day |
| Inclination | 2.6338° |
| Longitude of ascending node | 241.26° |
| 251.92° | |
| Physical characteristics | |
| Dimensions | 6.655±0.069[4] 6.712±0.041 km[5] 7.14 km (calculated)[3] |
| Rotation period | 4.969±0.003 h[lower-alpha 1] 4.97347±0.00005 h[6] 5.032±0.001 h[7] |
| Geometric albedo | 0.24 (assumed)[3] 0.3266±0.0245[5] 0.332±0.088[4] |
| S [3] | |
| Absolute magnitude (H) | 12.7[5] · 13.0[1][3] · 13.35±0.32[8] |
4606 Saheki, provisional designation 1987 UM1, is a stony Flora asteroid from the inner regions of the asteroid belt, approximately 7 kilometers in diameter.
The asteroid was discovered on 27 October 1987, by Japanese astronomer Tsutomu Seki at Geisei Observatory, Japan.[9] It was later named after Japanese astronomer Tsuneo Saheki.[2]
Classification and orbit
Saheki is a member of the Flora family, one of the largest families of stony asteroids. It orbits the Sun in the inner main-belt at a distance of 2.0–2.5 AU once every 3 years and 5 months (1,234 days). Its orbit has an eccentricity of 0.10 and an inclination of 3° with respect to the ecliptic.[1] The first precovery was taken at Palomar Observatory in 1953, extending the asteroid's observation arc by 34 years prior to its discovery.[9]
Physical characteristics
Rotation period
In January 2009, a rotational lightcurve of Saheki was obtained from photometric observations by David Higgins at Hunters Hill Observatory, Australia. Lightcurve analysis rendered a well-defined rotation period of 4.969 hours with a brightness variation of 0.56 in magnitude ({{{1}}}).[lower-alpha 1]
Two months later, in March 2009, a second lightcurve was obtained at the Via Capote Observatory (G69), California. It gave a period of 5.032 and an amplitude of 0.68 in magnitude ({{{1}}}).[7]
Spin axis
In 2013, an international study modeled a lightcurve with a concurring period of 4.97347 hours and found a spin axis of (44.0°, 59.0°) and (222.0°, 68.0°) in ecliptic coordinates (λ, β), respectively ({{{1}}}).[6]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Saheki has a high albedo of 0.33 and a diameter of 6.7 kilometers,[4][5] while the Collaborative Asteroid Lightcurve Link calculates a diameter of 7.1 kilometers, based on an assumed albedo of 0.24, derived from 8 Flora, the Flora family's namesake and largest member.[3]
Naming
This minor planet was named after Japanese astronomer and president of the Toa Astronomical Society, Tsuneo Saheki (1916–1996). Over half a century, Saheki as gathered large inventory of observational data of the planet Mars.[2] The Martian crater Saheki is also named in his honour. The official naming citation was published by the Minor Planet Center on 28 May 1991 (M.P.C. 18308).[10]
Notes
- ↑ 1.0 1.1 Higgins (2011) web: rotation period 4.969±0.003 hours with a brightness amplitude of 0.56 mag. The Collaborative Asteroid Lightcurve Link assigns a quality code of U=3 to the period solution, which denotes a secure result within the precision given and no ambiguity. Summary figures for (4606) Saheki at Collaborative Asteroid Lightcurve Link (CALL)
References
- ↑ 1.0 1.1 1.2 1.3 "JPL Small-Body Database Browser: 4606 Saheki (1987 UM1)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2004606.
- ↑ 2.0 2.1 2.2 Schmadel, Lutz D. (2007). "(4606) Saheki". Dictionary of Minor Planet Names – (4606) Saheki. Springer Berlin Heidelberg. p. 396. doi:10.1007/978-3-540-29925-7_4531. ISBN 978-3-540-00238-3.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 "LCDB Data for (4606) Saheki". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=4606%7CSaheki.
- ↑ 4.0 4.1 4.2 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. Bibcode: 2011ApJ...741...68M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...68M. Retrieved 5 December 2016.
- ↑ 5.0 5.1 5.2 5.3 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. Bibcode: 2011ApJ...741...90M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...90M. Retrieved 23 January 2016.
- ↑ 6.0 6.1 Hanus, J.; Broz, M.; Durech, J.; Warner, B. D.; Brinsfield, J.; Durkee, R. et al. (November 2013). "An anisotropic distribution of spin vectors in asteroid families". Astronomy and Astrophysics 559: 19. doi:10.1051/0004-6361/201321993. Bibcode: 2013A&A...559A.134H. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2013A&A...559A.134H. Retrieved 23 January 2016.
- ↑ 7.0 7.1 Brinsfield, James W. (July 2009). "Asteroid Lightcurve Analysis at the Via Capote Observatory: 2009 1st Quarter". The Minor Planet Bulletin 36 (3): 127–128. ISSN 1052-8091. Bibcode: 2009MPBu...36..127B. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2009MPBu...36..127B. Retrieved 23 January 2016.
- ↑ 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. Bibcode: 2015Icar..261...34V. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V. Retrieved 26 April 2016.
- ↑ 9.0 9.1 "4606 Saheki (1987 UM1)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=4606.
- ↑ "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html.
External links
- Asteroid Lightcurve Database (LCDB), query form (info )
- 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
- 4606 Saheki at AstDyS-2, Asteroids—Dynamic Site
- 4606 Saheki at the JPL Small-Body Database
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