The Spectroscopic Orbit of 56deg 2617
Abstract
The star 56 deg 2617 is one of the absorption line O-type stars whose investigation is being undertaken at Victoria and the orbit was required to obtain the velocity of the system and the mass function. The spectrum contains practically only the Balmer lines of hydrogen and the lines of enhanced helium with traces of ordinary helium and may be assigned to the spectral class O6 with a probable temperature of 21000 deg K. The orbit was obtained from 28 spectra and was corrected by least-squares. The period 1.36372 days, the eccentricity 0.3336, the semi-amplitude 77.01 km., and the longitude of the apse 289deg.94 form the principal elements. The projected semi-axis major is 1,354,500 km. and the mass function 0.054 solar masses. The latter, small for a high temperature star, indicates relatively small mass unless the ratio of masses of the components or the inclination of the orbital plane is large. The velocity of the system -1.04 km. per second is so widely different from the velocity -18.5 km. given by the stationary H and K lines as to indicate that the calcium vapor cannot be connected with the star.
- Publication:
-
Publications of the Dominion Astrophysical Observatory Victoria
- Pub Date:
- August 1923
- Bibcode:
- 1923PDAO....2..269P