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Chris Copperwheat

I am a postdoctoral research fellow in the Astronomy & Astrophysics group at the University of Warwick. I joined in November 2006 after completing my PhD at the Mullard Space Science Laboratory.


Research Interests

Cataclysmic variables: CVs are close binaries consisting of a white dwarf accreting matter from a main sequence donor star, and provide us with a large, homogeneous and easily observed population which can be compared to theoretical predictions. My interests are focused in the time domain, including photometric studies of eclipsing systems (using data obtained with ULTRACAM), time resolved spectroscopy (with VLT/X-shooter, and other facilities) and astroseismology (ULTRACAM; LT/RISE).

Ultracompact binaries: With periods in the range 5 – 65 min, the shortest of any known binary subclass, ultracompact binaries are thought to consist of a white dwarf accreting mass from a donor star which is also at least partially degenerate. These systems are of interest from a binary evolution point of view and as potential SN Ia progenitors. My main interest in this area is the detection of the gravitational radiation via changes in the orbital period, and to that end I am involved in the long-term monitoring of a number of systems.

Subdwarfs: Subdwarf B (sdB) stars are hot, sub-luminous stars which are thought to be core-helium burning with thin hydrogen envelopes. The main mechanism by which these stars lose their envelopes is thought to be binary star interaction. SdB stars are a 'clean' binary population relatively free of selection effects, and therefore are a strong test of population synthesis models. Since 2000 we have conducted a programme of radial velocity measurements of these stars with INT/IDS and LT/FRODOSPEC. Of the ~100 known sdB binaries, 51 have been discovered via our radial velocity programme.

Exoplanets: The same techniques which are used to model eclipsing binary stars can be applied to exoplanets. A recent interest of mine is the exploitation of multiband ULTRACAM photometry of transiting exoplanets. The aim is to probe the atmospheric composition of these planets.

Ultraluminous X-ray Sources: ULXs are point like, non-nuclear X-ray with luminosities in excess of the Eddington luminosity for a stellar mass black hole. The emission might be beamed or super-Eddington, but a popular explanation is that the compact object in these systems is an intermediate mass black hole (M > 100Msun). As part of my PhD studies I constructed the first model for the optical counterparts of these sources, accounting for the emission from the X-ray irradiated donor star and accretion disc


Recent (first author) publications

Copperwheat C.M., Marsh T.R., Parsons S. et al., 2012, MNRAS, 421, 149
A J-band detection of the donor star in the dwarf nova OY Carinae, and an optical detection of its ‘iron curtain’

Copperwheat C.M., Morales-Rueda L., Marsh T.R. et al., 2011, MNRAS, 415, 1381
Radial-velocity measurements of subdwarf B stars

Copperwheat C.M., Marsh T.R., Dhillon V.S. et al., 2011, MNRAS, 413, 3068
The photometric period in ES Ceti

Copperwheat C.M., Marsh T.R., Littlefair S.P. et al., 2011, MNRAS, 410, 1113
SDSS J0926+3624: the shortest period eclipsing binary star

A complete publication list can be found here (ADS).

Chris Copperwheat


Write to:

C.M. Copperwheat,
Department of Physics,
University of Warwick,
Coventry, CV4 7AL
 

Contact Details:

Office: PS 005a
Telephone:
+44 (0)24765 74329
Fax:
+44 (0)24766 92016
E-Mail: c.copperwheat (at) warwick.ac.uk