The OmegaWhite survey for short-period variable stars - VII. High amplitude short-period blue variables

Ramsay G, Woudt PA, Kupfer T, Van Roestel J, Paterson K, Warner B, Buckley DAH, Groot PJ, Heber U, Irrgang A, Jeffery CS, Motsoaledi M, Schwartz MJ, Wevers T (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Monthly Notices of the Royal Astronomical Society Oxford University Press

Book Volume: 513

Pages Range: 2215-2225

Journal Issue: 2

DOI: 10.1093/mnras/stac1000

Abstract

Blue Large-Amplitude Pulsators (BLAPs) are a relatively new class of blue variable stars showing periodic variations in their light curves with periods shorter than a few tens of minutes and amplitudes of more than 10 per cent. We report nine blue variable stars identified in the OmegaWhite survey conducted using ESO's VST, which shows a periodic modulation in the range 7-37 min and an amplitude in the range 0.11-0.28 mag. We have obtained a series of followup photometric and spectroscopic observations made primarily using SALT and telescopes at SAAO. We find four stars which we identify as BLAPs, one of which was previously known. One star, OW J0820-3301, appears to be a member of the V361 Hya class of pulsating stars and is spatially close to an extended nebula. One further star, OW J1819-2729, has characteristics similar to the sdAV pulsators. In contrast, OW J0815-3421 is a binary star containing an sdB and a white dwarf with an orbital period of 73.7 min, making it only one of six white dwarf-sdB binaries with an orbital period shorter than 80 min. Finally, high cadence photometry of four of the candidate BLAPs show features that we compare with notch-like features seen in the much longer period Cepheid pulsators.

Authors with CRIS profile

Ulrich Heber Professur für Astronomie und Astrophysik Andreas Irrgang Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut

Involved external institutions

Armagh Observatory GB United Kingdom (GB) University of Cape Town (UCT) ZA South Africa (ZA) Texas Tech University (TTU) US United States (USA) (US) California Institute of Technology (Caltech) US United States (USA) (US) European Southern Observatory (ESO) DE Germany (DE)

How to cite

APA:

Ramsay, G., Woudt, P.A., Kupfer, T., Van Roestel, J., Paterson, K., Warner, B.,... Wevers, T. (2022). The OmegaWhite survey for short-period variable stars - VII. High amplitude short-period blue variables. Monthly Notices of the Royal Astronomical Society, 513(2), 2215-2225. https://dx.doi.org/10.1093/mnras/stac1000

MLA:

Ramsay, Gavin, et al. "The OmegaWhite survey for short-period variable stars - VII. High amplitude short-period blue variables." Monthly Notices of the Royal Astronomical Society 513.2 (2022): 2215-2225.

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