Detection of Photometric Variations in the sdBV Star JL 166

The Astronomical Journal (Impact Factor: 4.02). 06/2009; 138(2). DOI: 10.1088/0004-6256/138/2/686
Source: arXiv


We report the discovery of oscillations in the hot subdwarf B star JL 166
from time-series photometry using the Goodman Spectrograph on the 4.1-m
Southern Astrophysical Research Telescope. Previous spectroscopic and
photometric observations place the star near the hot end of the empirical sdB
instability strip and imply the presence of a cool companion. Amplitude spectra
of the stellar light curve reveal at least 10 independent pulsation modes with
periods ranging from 97 to 178 s and amplitudes from 0.9 to 4 mma. We adopt
atmospheric parameters of T_eff = 34350 K and log g = 5.75 from a model
atmosphere analysis of our time-averaged, medium-resolution spectrum.

Download full-text


Available from: B. N. Barlow, Apr 20, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Context. A search programme for pulsating subdwarf B stars was conducted with the Nordic Optical Telescope on La Palma over 59 nights between 1999 and 2009. Aims: The purpose of the programme was to significantly extend the number of rapidly pulsating sdB stars to better understand the properties of this new group of variable compact stars. Methods: Candidates were selected initially from the HS and HE surveys, but were supplemented with additional objects from other surveys. Short sequences of time-series photometry were made on the candidates to determine the presence of rapid pulsations. Results: In total twenty new pulsators were found in this survey, most of which have already been published and some extensively studied. We present four new short period pulsators, bringing the total of such pulsators up to 49. We also give limits on pulsation amplitudes for 285 objects with no obvious periodic variations, summarise the results of the survey, and provide improved physical parameters on the composite pulsators for which only preliminary estimates were published earlier. Full Table 5 is only available in electronic form at the CDS via anonymous ftp to ( or via
    Full-text · Article · Apr 2010 · Astronomy and Astrophysics
  • [Show abstract] [Hide abstract]
    ABSTRACT: About half of the hot subdwarfs are found to have spectra of composite types, indicating a main sequence companion of spectral type F-K, and the pulsators are no exception to this rule. The spectroscopic contamination from the main sequence stars makes it hard to reliably establish physical parameters for the hot component, and also makes pulsations harder to detect as the amplitudes are depressed. The binary fraction of the observed sample of hot subdwarf pulsators is discussed, as are the biases that are affecting it. Spectroscopic evidence is presented that clearly demonstrates that the well known sdB pulsator, EO Ceti, is misclassified, and is actually an sdOV star.
    No preview · Article · Mar 2012