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.

Discovery ^[1]
Shape model of Ishihara from its lightcurve
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)^[2]
Alternative designations	1993 HS · 1991 YC₂ 1996 EU₁
Minor planet category	main-belt ^[1]^[3] · Flora ^[4]
Orbital characteristics ^[3]
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° 18^m 21.24^s / day
Inclination	2.7482°
Longitude of ascending node	20.550°
\|{{{apsis}}}\|helion}}	246.01°
Physical characteristics
Dimensions	4.986±0.053 km^[5] 5.012±0.069 km^[6]
Rotation period	6.715±0.0036 h^[7] 6.71574±0.00001 h^[8]
Pole ecliptic latitude	(42.0°, 76.0°) (λ₁/β₁)^[8]
Geometric albedo	0.2328±0.0281^[6] 0.235±0.027^[5]
Spectral type	S (assumed)^[4]
Absolute magnitude (H)	13.7^[6] · 13.9^[3] · 13.852±0.006 (R)^[7] · 14.3^[4]