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McAllister, MJ, Littlefair, SP, Baraffe, I, Dhillon, VS, Marsh, TR, Bento, J, Bochinski, J, Bours, MCP, Breedt, E, Copperwheat, CM, Hardy, LK, Kerry, P, Parsons, SG, Rostron, JW, Sahman, DI, Savoury, CDJ and Tunnicliffe, RL (2015) PHL 1445: An eclipsing cataclysmic variable with a substellar donor near the period minimum. Monthly Notices of the Royal Astronomical Society, 451 (1). pp. 114-125. ISSN 1365-2966
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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. Averaging four eclipses reveals resolved eclipses of the white dwarf and bright spot. We determined the system parameters by fitting a parameterised eclipse model to the averaged lightcurve. We obtain a mass ratio of q = 0.087 +- 0.006 and inclination i = 85.2 +- 0.9 degrees. The primary and donor masses were found to be Mw = 0.73 +- 0.03 Msun and Md = 0.064 +- 0.005 Msun, respectively. Through multicolour photometry a temperature of the white dwarf of Tw = 13200 +- 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 Myrs 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. These 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.
| Item Type: | Article |
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| Additional Information: | This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record MNRAS (July 21, 2015) 451 (1): 114-125 is available online at: http://dx.doi.org/10.1093/mnras/stv956 |
| Uncontrolled Keywords: | astro-ph.SR; astro-ph.SR |
| Subjects: | Q Science > QB Astronomy |
| Divisions: | Astrophysics Research Institute |
| Publisher: | Oxford University Press |
| Related URLs: | |
| Date Deposited: | 07 May 2015 13:59 |
| Last Modified: | 04 Sep 2021 14:26 |
| DOI or ID number: | 10.1093/mnras/stv956 |
| URI: | https://researchonline.ljmu.ac.uk/id/eprint/1021 |
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