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

doi:10.1093/mnras/stv956

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

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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 (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 M_w = 0.73 ± 0.03 M_⊙ and M_d = 0.064 ± 0.005 M_⊙, respectively. Through multicolour photometry a temperature of the white dwarf of T_w = 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 language	English
Pages (from-to)	114-125
Number of pages	12
Journal	Monthly Notices of the Royal Astronomical Society
Volume	451
Issue number	1
DOIs	https://doi.org/10.1093/mnras/stv956
Publication status	Published - 21 Jul 2015

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

McAllister, M. J. ; Littlefair, S. P. ; Baraffe, I. ; Dhillon, V. S. ; Marsh, T. R. ; Bento, J. ; Bochinski, J. ; Bours, M. C P ; Breedt, E. ; Copperwheat, C. M. ; Hardy, L. K. ; Kerry, P. ; Parsons, S. G. ; Rostron, J. W. ; Sahman, D. I. ; Savoury, C. D J ; Tunnicliffe, R. L. / PHL 1445 : an eclipsing cataclysmic variable with a substellar donor near the period minimum. In: Monthly Notices of the Royal Astronomical Society. 2015 ; Vol. 451, No. 1. pp. 114-125.

@article{8822c18baba646b4a44d15947973c556,

title = "PHL 1445: an eclipsing cataclysmic variable with a substellar donor near the period minimum",

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.",

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

year = "2015",

month = jul,

day = "21",

doi = "10.1093/mnras/stv956",

language = "English",

volume = "451",

pages = "114--125",

journal = "Monthly Notices of the Royal Astronomical Society: Letters",

issn = "1745-3925",

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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 & Tunnicliffe, RL 2015, 'PHL 1445: an eclipsing cataclysmic variable with a substellar donor near the period minimum', Monthly Notices of the Royal Astronomical Society, vol. 451, no. 1, pp. 114-125. https://doi.org/10.1093/mnras/stv956

PHL 1445 : an eclipsing cataclysmic variable with a substellar donor near the period minimum. / McAllister, M. J.; Littlefair, S. P.; Baraffe, I.; Dhillon, V. S.; Marsh, T. R.; Bento, J.; Bochinski, J.; Bours, M. C P; Breedt, E.; Copperwheat, C. M.; Hardy, L. K.; Kerry, P.; Parsons, S. G.; Rostron, J. W.; Sahman, D. I.; Savoury, C. D J; Tunnicliffe, R. L.

In: Monthly Notices of the Royal Astronomical Society, Vol. 451, No. 1, 21.07.2015, p. 114-125.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - PHL 1445

T2 - an eclipsing cataclysmic variable with a substellar donor near the period minimum

AU - McAllister, M. J.

AU - Littlefair, S. P.

AU - Baraffe, I.

AU - Dhillon, V. S.

AU - Marsh, T. R.

AU - Bento, J.

AU - Bochinski, J.

AU - Bours, M. C P

AU - Breedt, E.

AU - Copperwheat, C. M.

AU - Hardy, L. K.

AU - Kerry, P.

AU - Parsons, S. G.

AU - Rostron, J. W.

AU - Sahman, D. I.

AU - Savoury, C. D J

AU - Tunnicliffe, R. L.

PY - 2015/7/21

Y1 - 2015/7/21

N2 - 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.

AB - 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.

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U2 - 10.1093/mnras/stv956

DO - 10.1093/mnras/stv956

M3 - Article

AN - SCOPUS:84938237229

VL - 451

SP - 114

EP - 125

JO - Monthly Notices of the Royal Astronomical Society: Letters

JF - Monthly Notices of the Royal Astronomical Society: Letters

SN - 1745-3925

IS - 1

ER -

PHL 1445: an eclipsing cataclysmic variable with a substellar donor near the period minimum

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