1245 Calvinia
1245 Calvinia is a stony Koronian asteroid from the outer regions of the asteroid belt, approximately in diameter. It was discovered on 26 May 1932, by South African astronomer Cyril Jackson at the Union Observatory in Johannesburg. The S-type asteroid is likely elongated and has a rotation period of 4.9 hours. It was named for the city of Calvinia in South Africa.
Orbit and classification
According to Zappalà, Mothé-Diniz, as well as Milani and Knežević, Calvinia is a member of the Koronis family, a very large outer asteroid family with nearly co-planar ecliptical orbits. Interestingly, in one of the most recent and complete synthetic HCM-analysis by Nesvorný, Calvinia is not a Koronian asteroid but belongs to the background population.It orbits the Sun in the outer main-belt at a distance of 2.7–3.1 AU once every 4 years and 11 months. Its orbit has an eccentricity of 0.08 and an inclination of 3° with respect to the ecliptic. The asteroid was first observed as at the Heidelberg Observatory in March 1906. The body's observation arc begins with its official discovery observation at Johannesburg in May 1932.
Naming
This minor planet was named after the regional city Calvinia in the Cape Province of South Africa. The official was mentioned in The Names of the Minor Planets by Paul Herget in 1955.Physical characteristics
In the Tholen classification, Calvinia is a common stony S-type asteroid, which is also the overall spectral type for members of the Koronis family. In the Barucci taxonomy, it is an S0-type asteroid.Rotation period
In October 2017, a rotational lightcurve of Calvinia was obtained from photometric observations by Romain Montaigut, Christophe Gillier and Arnaud Leroy. Lightcurve analysis gave a rotation period of hours with a brightness variation of 0.28 magnitude.Other rotational were obtained by Brines in 2016, by Lagerkvist and in 1975 and 1978, respectively, by Erikson in 1990, by Slivan in 2002, by Roy, and by Tedesco in 1979.
A modeled lightcurve using photometric data from the Lowell Photometric Database was published in 2016. It gave a concurring period of hours, as well as two spin axes at and in ecliptic coordinates.