364 Isara[c] 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.[16] The asteroid was named after the Isère River in France.[5]
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.[16]
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 led 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][8]
The results agree with the first rotational lightcurve was already obtained in the 1960s (U=2).[a]
Spin axis
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]
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.[6]
364 Isara has been observed to occult 4 stars between 2002 and 2023.
^ abYang (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)
^ abcdMasiero, 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. S2CID46350317.
^ abWarner, 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. ISSN1052-8091.