Mouvement orbital de la cepheide naine SZ LYN.
Abstract
The dwarf cepheid SZ Lyn, whose binarity, first suspected in 1967, was established in 1981, was observed from 1979 November 27 to 1983 November 21 with the CORAVEL photoelectric spectrometer. Measurements secured over 30 pulsational cycles yield a sequence of 21 mean radial velocity values. Taking previous observations into account, we derive a period longer than was supposed previously: P = 1181.5 ± 1.4days. The other orbital elements, calculated with CORAVEL results only, are the following: T0 = 2445804.9 ± 7.9 JD e = 0.191 ± 0.008 K = 9.56 ± 0.09 km s-1 V0 = 34.17 ± 0.05 km s-1 ω = 100°.6 ± 2°.7 a1 sin i = (152.4 ± 1.6). 106 km = 219.3 ± 2.3 Rsun ƒ(M) = 0.101 ± 0.003 Msun. The radial velocity curve is accurate to 0.20km s-1. Data from previous publications (Mv = 1.87 or Mv = 2.92 at minimum light) are consistent with an F0 IV-V or an F2 III-IV spectral type, and we find the secondary component to be cooler than F2 V or G2 V. The distance between the two components lies in the range of 573 to 672 Rsun. The system is separated, with an orbit inclination greater than 50°, and its distance from us is found to be 365 pc or 225 pc, depending upon the assumed absolute magnitude.
- Publication:
-
Astronomy and Astrophysics Supplement Series
- Pub Date:
- August 1984
- Bibcode:
- 1984A&AS...57..249B
- Keywords:
-
- Binary Stars;
- Cepheid Variables;
- Dwarf Stars;
- Stellar Motions;
- Radial Velocity;
- Stellar Spectra;
- Astronomy