190 Ismene

190 Ismene

Discovery
Discovered by	C. H. F. Peters, 1878
Discovery date	22 September 1878
Designations
Minor planet category	Main belt (Hilda)
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	121.44 yr (44357 d)
Aphelion	4.6480 AU (695.33 Gm)
Perihelion	3.3248 AU (497.38 Gm)
Semi-major axis	3.9864 AU (596.36 Gm)
Eccentricity	0.16597
Orbital period	7.96 yr (2907.2 d)
Mean anomaly	134.92°
Mean motion	0° 7^m 25.788^s / day
Inclination	6.1772°
Longitude of ascending node	175.48°
Argument of perihelion	271.47°
Earth MOID	2.34759 AU (351.194 Gm)
Jupiter MOID	0.773933 AU (115.7787 Gm)
Jupiter Tisserand parameter	3.022
Physical characteristics
Mean radius	79.5 km[1] 90 km[2]
Rotation period	6.52 h (0.272 d)^3
Geometric albedo	0.066
Spectral type	P
Absolute magnitude (H)	7.77[3] 7.59[1]

190 Ismene is a very large main belt asteroid. It was discovered by German-American astronomer C. H. F. Peters on September 22, 1878 in Clinton, New York and named after Ismene, the sister of Antigone in Greek mythology.

Being a P-type asteroid, it has a very dark surface. Ismene orbits near the outer edge of the asteroid belt. It is one of the largest members of the Hilda asteroid family, which are locked in 3:2 resonance with the planet Jupiter.^[4]

References

1. Yeomans, Donald K., "190 Ismene", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 6 May 2016.
3. Warner, Brian D. (December 2007), "Initial Results of a Dedicated H-G Project", The Minor Planet Bulletin 34, pp. 113–119, Bibcode:2007MPBu...34..113W.
4. Dahlgren, M.; Lagerkvist, C.-I. (October 1995), "A study of Hilda asteroids. I. CCD spectroscopy of Hilda asteroids", Astronomy and Astrophysics 302: 907, Bibcode:1995A&A...302..907D.

External links

• 190 Ismene at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters