PHL 1445

an eclipsing cataclysmic variable with a substellar donor near the period minimum

M. J. McAllister*, S. P. Littlefair, I. Baraffe, V. S. Dhillon, T. R. Marsh, J. Bento, J. Bochinski, M. C P Bours, E. Breedt, C. M. Copperwheat, L. K. Hardy, P. Kerry, S. G. Parsons, J. W. Rostron, D. I. Sahman, C. D J Savoury, R. L. Tunnicliffe

*Corresponding author for this work

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We present high-speed, three-colour photometry of the eclipsing dwarf nova PHL 1445, which, with an orbital period of 76.3 min, lies just below the period minimum of ~82 min for cataclysmic variable stars (CVs). Averaging four eclipses reveals resolved eclipses of the white dwarf and bright spot. We determined the system parameters by fitting a parametrized eclipse model to the averaged light curve. We obtain a mass ratio of q = 0.087 ± 0.006 and inclination i = 85°.2 ± 0°.9. The primary and donor masses were found to be Mw = 0.73 ± 0.03 M and Md = 0.064 ± 0.005 M, respectively. Through multicolour photometry a temperature of the white dwarf of Tw = 13 200 ± 700 K and a distance of 220 ± 50 pc were determined. The evolutionary state of PHL 1445 is uncertain. We are able to rule out a significantly evolved donor, but not one that is slightly evolved. Formation with a brown dwarf donor is plausible, though the brown dwarf would need to be no older than 600 Myr at the start of mass transfer, requiring an extremely low mass ratio (q = 0.025) progenitor system. PHL 1445 joins SDSS 1433 as a sub-period minimum CV with a substellar donor. The existence of two such systems raises an alternative possibility that current estimates for the intrinsic scatter and/or position of the period minimum may be in error.

Original languageEnglish
Pages (from-to)114-125
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume451
Issue number1
DOIs
Publication statusPublished - 21 Jul 2015

Fingerprint Dive into the research topics of 'PHL 1445: an eclipsing cataclysmic variable with a substellar donor near the period minimum'. Together they form a unique fingerprint.

  • Cite this

    McAllister, M. J., Littlefair, S. P., Baraffe, I., Dhillon, V. S., Marsh, T. R., Bento, J., ... Tunnicliffe, R. L. (2015). PHL 1445: an eclipsing cataclysmic variable with a substellar donor near the period minimum. Monthly Notices of the Royal Astronomical Society, 451(1), 114-125. https://doi.org/10.1093/mnras/stv956