9971 Ishihara

9971 Ishihara
	Shape model of Ishihara from its lightcurve
Discovery
Discovered by	K. Endate; K. Watanabe
Discovery site	Kitami Observatory
Discovery date	16 April 1993
Designations
MPC designation	(9971) Ishihara
Named after	Takahiro Ishihara; (Japanese astronomer)
Alternative designations	1993 HS · 1991 YC2; 1996 EU1
Minor planet category	main-belt · Flora
Orbital characteristics
	Epoch 4 September 2017 (JD 2458000.5)
	Uncertainty parameter 0
Observation arc	24.91 yr (9,097 days)
\|{{{apsis}}}\|helion}}	2.4465 AU
\|{{{apsis}}}\|helion}}	1.9164 AU
Semi-major axis	2.1814 AU
Eccentricity	0.1215
Orbital period	3.22 yr (1,177 days)
Mean anomaly	158.69°
Mean motion	0° 18m 21.24s / day
Inclination	2.7482°
Longitude of ascending node	20.550°
\|{{{apsis}}}\|helion}}	246.01°
Physical characteristics
Dimensions	4.986±0.053 km; 5.012±0.069 km
Rotation period	6.715±0.0036 h; 6.71574±0.00001 h
Pole ecliptic latitude	(42.0°, 76.0°) (λ1/β1)
Geometric albedo	0.2328±0.0281; 0.235±0.027
Spectral type	S (assumed)
Absolute magnitude (H)	13.7 · 13.9 · 13.852±0.006 (R) · 14.3

Short description: Asteroid

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,^[1] and named after Takahiro Ishihara, president of the astronomical society at Hiroshima.^[2]

Orbit and classification

Orbit of Ishihara (blue), inner planets and Jupiter (outermost)

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.^[3] 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.^[1]

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).^[2] The official naming citation was published by the Minor Planet Center on 6 January 2003 (M.P.C. 47298).^[9]

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 ({{{1}}}).^[7]

A 2016-published lightcurve, using modeled photometric data from the Lowell Photometric Database (LPD), gave a concurring period of 6.71574 hours ({{{1}}}), as well as a spin axis of (42.0°, 76.0°) in ecliptic coordinates (λ, β).^[8]

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.^[5]^[6] 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.^[4]

References

↑ ^1.0 ^1.1 ^1.2 ^1.3 "9971 Ishihara (1993 HS)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=9971.
↑ ^2.0 ^2.1 ^2.2 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.
↑ ^3.0 ^3.1 ^3.2 ^3.3 "JPL Small-Body Database Browser: 9971 Ishihara (1993 HS)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2009971.
↑ ^4.0 ^4.1 ^4.2 ^4.3 "LCDB Data for (9971) Ishihara". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=9971.
↑ ^5.0 ^5.1 ^5.2 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 10 April 2017.
↑ ^6.0 ^6.1 ^6.2 ^6.3 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.
↑ ^7.0 ^7.1 ^7.2 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. doi:10.1088/0004-6256/150/3/75. Bibcode: 2015AJ....150...75W. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015AJ....150...75W. Retrieved 10 April 2017.
↑ ^8.0 ^8.1 ^8.2 Durech, J.; Hanus, J.; Oszkiewicz, D.; Vanco, R. (March 2016). "Asteroid models from the Lowell photometric database". Astronomy and Astrophysics 587: 6. doi:10.1051/0004-6361/201527573. Bibcode: 2016A&A...587A..48D. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2016A&A...587A..48D. Retrieved 10 April 2017.
↑ "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html.

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
- Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
9971 Ishihara at the JPL Small-Body Database
- Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

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Original source: https://en.wikipedia.org/wiki/9971 Ishihara. Read more

[MPC-object-1] 1.0 ^1.1 ^1.2 ^1.3 "9971 Ishihara (1993 HS)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=9971.

[springer-2] 2.0 ^2.1 ^2.2 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.

[jpldata-3] 3.0 ^3.1 ^3.2 ^3.3 "JPL Small-Body Database Browser: 9971 Ishihara (1993 HS)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2009971.

[lcdb-4] 4.0 ^4.1 ^4.2 ^4.3 "LCDB Data for (9971) Ishihara". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=9971.

[Masiero-2011-5] 5.0 ^5.1 ^5.2 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 10 April 2017.

[WISE-6] 6.0 ^6.1 ^6.2 ^6.3 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.

[Waszczak-2015-7] 7.0 ^7.1 ^7.2 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. doi:10.1088/0004-6256/150/3/75. Bibcode: 2015AJ....150...75W. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015AJ....150...75W. Retrieved 10 April 2017.

[Durech-2016-8] 8.0 ^8.1 ^8.2 Durech, J.; Hanus, J.; Oszkiewicz, D.; Vanco, R. (March 2016). "Asteroid models from the Lowell photometric database". Astronomy and Astrophysics 587: 6. doi:10.1051/0004-6361/201527573. Bibcode: 2016A&A...587A..48D. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2016A&A...587A..48D. Retrieved 10 April 2017.

[MPC-Circulars-Archive-9] "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html.

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