Shape model of Ishihara from its lightcurve | |
| Discovery | |
|---|---|
| Discovered by | K. Endate K. Watanabe |
| Discovery site | Kitami Observatory |
| Discovery date | 16 April 1993 |
| Designations | |
| (9971) Ishihara | |
Named after | Takahiro Ishihara (Japanese astronomer) |
| 1993 HS · 1991 YC2 1996 EU1 | |
| main-belt · Flora | |
| Orbital characteristics | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 24.91 yr (9,097 days) |
| Aphelion | 2.4465 AU |
| Perihelion | 1.9164 AU |
| 2.1814 AU | |
| Eccentricity | 0.1215 |
| 3.22 yr (1,177 days) | |
| 158.69° | |
| 0° 18m 21.24s / day | |
| Inclination | 2.7482° |
| 20.550° | |
| 246.01° | |
| Physical characteristics | |
| Dimensions | 4.986±0.053 km 5.012±0.069 km |
| 6.715±0.0036 h 6.71574±0.00001 h | |
Pole ecliptic latitude | (42.0°, 76.0°) (λ1/β1) |
| 0.2328±0.0281 0.235±0.027 | |
| S (assumed) | |
| 13.7 · 13.9 · 13.852±0.006 (R) · 14.3 | |
_Ishihara.png){kind=link}
9971 Ishihara (prov. designation: 1993 HS) is a stony Flora asteroid from the inner regions of the asteroid belt, approximately 5 kilometers (3.1 miles) in diameter. It was discovered by Japanese amateur astronomers Kin Endate and Kazuro Watanabe at Kitami Observatory on 16 April 1993, and named after Takahiro Ishihara, president of the astronomical society at Hiroshima.
Orbit and classification
Ishihara is a member of the Flora family, one of the largest families of stony asteroids in the asteroid belt. It orbits the Sun in the inner main-belt at a distance of 1.9–2.4 AU once every 3 years and 3 months (1,177 days). Its orbit has an eccentricity of 0.12 and an inclination of 3° with respect to the ecliptic. It was first identified as 1991 YC2 at Karl Schwarzschild Observatory in 1991, extending the body's observation arc by approximately 2 years prior to its official discovery at Kitami.
Naming
This minor planet was named after Takahiro Ishihara (born 1961), an observer of comets, communicator of astronomy, and former president of the astronomical society at Hiroshima (1987–1997). The official naming citation was published by the Minor Planet Center on 6 January 2003 (M.P.C. 47298).
Physical characteristics
Rotation and poles
In January 2012, a rotational lightcurve of Ishihara was obtained from photometric observations by astronomers at the Palomar Transient Factory in California. Lightcurve analysis gave a rotation period of 6.715±0.0036 hours with a brightness amplitude of 1.06 in magnitude, which indicates that the body has a non-spheroidal shape (U=2).
A 2016-published lightcurve, using modeled photometric data from the Lowell Photometric Database (LPD), gave a concurring period of 6.71574 hours (U=n.a.), as well as a spin axis of (42.0°, 76.0°) in ecliptic coordinates (λ, β).
Diameter and albedo
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Ishihara measures 4.986 and 5.012 kilometers in diameter and its surface has an albedo of 0.235 and 0.2328, respectively. The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, a S-type asteroid and the family's largest member and namesake – and calculates a diameter of 3.74 kilometers with an absolute magnitude of 14.3.
References
- ^ a b c d "9971 Ishihara (1993 HS)". Minor Planet Center. Retrieved 10 April 2017.
- ^ a b c Schmadel, Lutz D. (2006). "(9971) Ishihara [2.18, 0.12, 2.7]". Dictionary of Minor Planet Names – (9971) Ishihara, Addendum to Fifth Edition: 2003–2005. Springer Berlin Heidelberg. p. 49. doi:10.1007/978-3-540-34361-5_391. ISBN 978-3-540-34361-5.
- ^ a b c d "JPL Small-Body Database Browser: 9971 Ishihara (1993 HS)" (2016-11-23 last obs.). Jet Propulsion Laboratory. Retrieved 22 June 2017.
- ^ a b c d "LCDB Data for (9971) Ishihara". Asteroid Lightcurve Database (LCDB). Retrieved 10 April 2017.
- ^ a b c 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. Retrieved 10 April 2017.
- ^ a b c d 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.
- ^ a b c Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 10 April 2017.
- ^ a b c Durech, J.; Hanus, J.; Oszkiewicz, D.; Vanco, R. (March 2016). "Asteroid models from the Lowell photometric database". Astronomy and Astrophysics. 587: 6. arXiv:1601.02909. Bibcode:2016A&A...587A..48D. doi:10.1051/0004-6361/201527573. Retrieved 10 April 2017.
- ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 10 April 2017.
External links
- Lightcurve Database Query (LCDB), at www.minorplanet.info
- Dictionary of Minor Planet Names, Google books
- Asteroids and comets rotation curves, CdR – Geneva Observatory, Raoul Behrend
- Discovery Circumstances: Numbered Minor Planets (5001)-(10000) – Minor Planet Center
- 9971 Ishihara at AstDyS-2, Asteroids—Dynamic Site
- 9971 Ishihara at the JPL Small-Body Database