Photometry and spectroscopy of the new sdBV CS 1246

作者：Barlow B N^*; Dunlap B H; Clemens J C; Lynas Gray A E; Ivarsen K M; LaCluyze A P; Reichart D E; Haislip J B; Nysewander M C

来源：Monthly Notices of the Royal Astronomical Society, 2010, 403(1): 324-334.

DOI：10.1111/j.1365-2966.2009.16119.x

• stars: individual: CS 1246
• stars: oscillations
• subdwarfs

We report the discovery of a large-amplitude oscillation in the hot subdwarf B star CS 1246 and present multicolour photometry and time-resolved spectroscopy supporting this discovery. We used the 0.41-m Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes array to acquire data in the u', g', r' and i' filters simultaneously over three consecutive nights in 2009 April. These data reveal a single oscillation mode with a period of 371.707 +/- 0.002 s and an amplitude dependent upon wavelength, with a value of 34.5 +/- 1.6 mma in the u' filter. We detected no additional frequencies in any of the light curves. Subsequently, we used the 4.1-m SOAR telescope to acquire a time-series of 248 low-resolution spectra spanning 6 h to look for line profile variations. Models fits to the spectra give mean atmospheric values of T(eff) = 28 450 +/- 700 K and log g = 5.46 +/- 0.11 undergoing variations with semi-amplitudes of 507 +/- 55 K and 0.034 +/- 0.009, respectively. We also detect a radial velocity oscillation with an amplitude of 8.8 +/- 1.1 km s-1. The relationship between the angular and physical radii variations shows that the oscillation is consistent with a radial mode. Under the assumption of a radial pulsation, we compute the stellar distance, radius and mass as d = 460 +/- 190(90) pc, R = 0.19 +/- 0.08 R(circle dot) and M = 0.39 +/- 0.30(0.13) M(circle dot), respectively, using the Baade-Wesselink method.

• 出版日期2010-3-21