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Jan van Roestel

PhD student at the Department of Astrophysics of the Radboud University Nijmegen.

Visiting address: Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
Postal addres: P.O. Box 9010, 6500 GL Nijmegen, The Netherlands

Location: Huygens building
Room: 02.738
Telephone: +31 (0) 24 36 52823
Telefax: +31 (0) 24 36 52807
Email: j.vanroestel at astro.ru.nl
Resume

Fast optical transient

The subject I am currently working on are fast optical transients.

Compact binaries

Eclipsing binary star Another subject I am interested in are compact binary star. Specifically, binary stars containing white dwarfs, subdwarf B/O stars and related objects. The topic of my bachelor thesis is a pulsating SdO star, which are often found in a binary system with a short orbital periods. My work for my Master thesis about a eclipsing Post Common Envelope Binary (PCEB, also known as a pre-CV). I used high cadence ULTRACAM photometry with radial velocity measurements, to determine the mass and radius of both components. The figure to the right visualises the white dwarf in blue and the red dwarf in red. The yellow shade indicates the irradiation of the red dwarf by the white dwarf.









EL CVn binaries in PTF

Colourplot EL CVn binaries are eclipsing pre-white dwarfs and A-main sequence stars. The light curve of these systems shows shallow eclipses, 0.1 mag or less, and the targets are relativly blue. This type of binary was first discovered by the kepler satellite. Indications are that these systems are quite common, and SWASP found 17 of these systems (V<13). I have used PTF light curve statistics and PANSTARRS colours to find new systems. I trained a machine learning classifier to find more of these systems. Using this method we find a total of 36 new EL CVn binaries in the PTF light curve database. The figure shows a 3D view of the colour parameter space and the location of the EL CVn systems. I have also applied ML methods to find more eclipsing WD-RD systems in the PTF database. These are shown as yellow in the 3D figure.

Publications
My publications at ADS.
Master Thesis

The subject of my Master Thesis is PTF1108ag, a new eclipsing white dwarf red dwarf binary star. This research was carried out during 2012-2013, the second year of my Master education.

Bachelor Thesis

A the end of my Bachelor eduation I did a 3 month project, analysing spectra of pulsating SdO star SDSS J160043.6+074802.9 (found by Woudt et al. 2006 ). The report of my Bachelor thesis can be found here.