364 Isara

Isara[16] (minor planet designation: 364 Isara) is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 27 kilometers in diameter. It was discovered on 19 March 1893, by French astronomer Auguste Charlois at the Nice Observatory in southeast France.[17] The asteroid was named after the Isère River in France.[2]

364 Isara
Discovery [1]
Discovered byA. Charlois
Discovery siteNice Obs.
Discovery date19 March 1893
(364) Isara
Named after
Isère River
(river in France)[2]
1893 T · 1976 AB
main-belt · (inner)
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc117.10 yr (42,772 days)
Aphelion2.5532 AU
Perihelion1.8881 AU
2.2206 AU
3.31 yr (1,209 days)
0° 17m 52.08s / day
Physical characteristics
Dimensions25.901±0.665 km[9]
27.99±1.0 km[10]
28.78±0.30 km[11]
35.209±0.253 km[12]
9.151±0.007 h[13]
9.155 h[a]
9.156±0.001 h[14][b]
9.1570±0.0005 h[5]
9.15751±0.00005 h[15]
Tholen = S[1] · S[3]
B–V = 0.912 [1]
U–B = 0.538 [1]

Orbit and classificationEdit

Isara is a member of the Flora family (402), a giant asteroid family and the largest family of stony asteroids in the main-belt.[3][4][18]: 23 

It orbits the Sun in the inner main-belt at a distance of 1.9–2.6 AU once every 3 years and 4 months (1,209 days). Its orbit has an eccentricity of 0.15 and an inclination of 6° with respect to the ecliptic.[1] The body's observation arc begins at Vienna Observatory in April 1900, seven years after to its official discovery observation at Nice.[17]

Physical characteristicsEdit

In the Tholen classification, Isara is a common stony S-type asteroid, which agrees with the overall spectral type of the Flora family.[1][18]: 23 

Rotation periodEdit

In 2009, photometric observations of Isara were made by American astronomer Brian Warner at the Palmer Divide Observatory (716) in Colorado,[b] by amateur astronomer René Roy at Blauvac Observatory (627) in France, and by a group of Polish astronomers lead by Agnieszka Kryszczyńska of the Polish Astronomical Society. The resulting asymmetrical lightcurves showed a synodic rotation period between 9.151 and 9.157 hours with a brightness variation between 0.30 and 0.40 in magnitude (U=3/3/2+).[13][14][5]

The results agree with the first rotational lightcurve was already obtained in the 1960s (U=2).[a]

Spin axisEdit

In 2013, an international study modeled a lightcurve with a concurring period of 9.15751 hours and found two spin axis of (282.0°, 44.0°) and (86.0°, 42.0°) in ecliptic coordinates (λ, β) (Q=2).[15]

Diameter and albedoEdit

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Isara measures between 25.901 and 35.209 kilometers in diameter and its surface has an albedo between 0.1625 and 0.300.[9][10][11][12]

The Collaborative Asteroid Lightcurve Link adopt the results obtained by IRAS, that is, an albedo of 0.2566 and a diameter of 27.99 kilometers based on an absolute magnitude of 9.86.[3]


This minor planet was named after the Isère River in south eastern France. ("Isara" is an early name for this river.) The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 40).[2]


  1. ^ a b Yang (1965) web: rotation period 9.155 hours with a brightness amplitude of 0.35 mag. Quality Code of 2. Summary figures for (364) Isara at Collaborative Asteroid Lightcurve Link (CALL)
  2. ^ a b Lightcurve plot of 364 Isara, Palmer Divide Observatory, Brian D. Warner (2009)


  1. ^ a b c d e f g h "JPL Small-Body Database Browser: 364 Isara (1893 T)" (2017-06-06 last obs.). Jet Propulsion Laboratory. Archived from the original on 15 September 2020. Retrieved 5 September 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (364) Isara. Springer Berlin Heidelberg. p. 45. doi:10.1007/978-3-540-29925-7_365. ISBN 978-3-540-00238-3.
  3. ^ a b c d e "LCDB Data for (364) Isara". Asteroid Lightcurve Database (LCDB). Retrieved 5 September 2017.
  4. ^ a b "Asteroid 364 Isara – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 24 October 2019.
  5. ^ a b c Kryszczynska, A.; Colas, F.; Polinska, M.; Hirsch, R.; Ivanova, V.; Apostolovska, G.; et al. (October 2012). "Do Slivan states exist in the Flora family?. I. Photometric survey of the Flora region". Astronomy and Astrophysics. 546: 51. Bibcode:2012A&A...546A..72K. doi:10.1051/0004-6361/201219199.
  6. ^ William Bolles (1846) A Phonographic Pronouncing Dictionary of the English Language
  7. ^ Walker (1830) A Key to the Classical Pronunciation of Greek, Latin, and Scripture Proper Names
  8. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  9. ^ a b c d 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. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8.
  10. ^ a b c d Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 22 October 2019.
  11. ^ a b c d 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. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)
  12. ^ 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.
  13. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (364) Isara". Geneva Observatory. Retrieved 5 September 2017.
  14. ^ a b Warner, Brian D. (October 2009). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2009 March-June". The Minor Planet Bulletin. 36 (4): 172–176. Bibcode:2009MPBu...36..172W. ISSN 1052-8091.
  15. ^ a b 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. arXiv:1309.4296. Bibcode:2013A&A...559A.134H. doi:10.1051/0004-6361/201321993.
  16. ^ with the stress on the 'i'
  17. ^ a b "364 Isara (1893 T)". Minor Planet Center. Retrieved 5 September 2017.
  18. ^ a b Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). Identification and Dynamical Properties of Asteroid Families. Asteroids IV. pp. 297–321. arXiv:1502.01628. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131.

External linksEdit