Photometry and spectroscopy of the new sdBV CS 1246

Abstract

We report the discovery of a large-amplitude oscillation in the hot subdwarf B star CS 1246 and present multi-colour photometry and time-resolved spectroscopy supporting this discovery. We used the 0.41-m PROMPT array to acquire data in the u', g', r', and i' filters simultaneously over 3 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 hrs to look for line profile variations. Models fits to the spectra give mean atmospheric values of Teff = 28450 +/- 700 K and log g = 5.46 +/- 0.11 undergoing variations with semi-amplitudes of 507 +/- 55 K and 0.034 +/- 0.009 dex, respectively. We also detect a radial velocity oscillation with an amplitude of 8.8 +/- 1.1 km/s. The relationship between the angular and physical radii variations shows 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 +/- 140 pc, R = 0.19 +/- 0.08 Rsun, and M = 0.39 +/- 0.22 Msun, respectively, using the Baade-Wesselink method.

12 pages, 11 figures, 3 tables. Accepted for publication in MNRAS

References in corpus (7)

• A binary model for the UV-upturn of elliptical galaxies (MNRAS version)
• Mode identification for Balloon 090100001 using combined multicolour photometry and spectroscopy
• A Quantitative Analysis of the Available Multicolor Photometry for Rapidly Pulsating Hot B Subdwarfs
• Observations and asteroseismic analysis of the rapidly pulsating hot B subdwarf PG 0911+456
• The planet-hosting subdwarf B star V391 Pegasi is a hybrid pulsator
• The masses of hot subdwarfs
• The MSST Campaign: II.Effective temperature and gravity variations in the multi-periodic pulsating subdwarf B star PG1605+072

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