Asteroid (15) Eunomia

Eunomia at Opposition in 2010

Eunomia will only just brighten to magnitude 9.0 at its opposition on 27 June 2010. The asteroid will be in Sagittarius between the end of May and beginning of August when it is brighter than magnitude 9.5. Throughout this period in will be moving in a retrograde sense, that is to the west through the stars.

Eunomia's orbital period is 4.30 years, its distance from the Sun varying between 2.15 and 3.14 AU, with an eccentricity of .186. Thus at the most favourable oppositions Eunomia is about 1.15 AU from the Earth when it will have a magnitude 7.9. At its opposition in 2010 it will be 1.77 AU from the Earth, so this is not a favourable opposition.

Eunomia's orbit is inclined at 11.750° to the ecliptic. The asteroid has a diameter about 272 km, making it about the eighth biggest asteroid. It was discovered in 1851 by A de Gasparis at Naples.

Chart showing path of Eunomia from the end if May to early August 2010.

The position of (1) Ceres is also marked for the end of May.

The chart is a southern hemisphere view with north at the bottom and east to the right. Stars to magnitude 9.0 are shown, which is about the limiting magnitude of 50 mm aperture binoculars. The circle on the chart represents a field of view 5° in diameter, a fairly typical field of view for binoculars.

Path of Eunomia winter 2010.

Positional data for Eunomia May to August 2010.

Date 2010	R.A hr min	Dec ° '	Mag.	Const
May 28	18 50.4	-30 00	9.6	Sagittarius
Jun 7	18 43.1	-29 50	9.4	Sagittarius
Jun 17	18 33.7	-29 33	9.2	Sagittarius
Jun 27	18 23.2	-29 07	9.0	Sagittarius
Jul 7	18 12.5	-28 33	9.1	Sagittarius
Jul 17	18 02.9	-27 51	9.3	Sagittarius
Jul 27	17 55.3	-27 04	9.4	Sagittarius
Aug 6	17 50.4	-26 18	9.6	Sagittarius

Royal Astronomical Society of New Zealand

The Brighter Asteroids in 2010: (15) Eunomia

Eunomia at Opposition in 2010

Chart showing path of Eunomia from the end if May to early August 2010.