Related papers: Discovery of a stripped red giant core in a bright…
Pulsating low-mass white dwarf stars are white dwarfs with stellar masses between 0.30~M$_{\odot}$ and 0.45~M$_{\odot}$ that show photometric variability due to gravity-mode pulsations. Within this mass range, they can harbour both a…
1SWASP J162545.15-043027.9 (WASP 1625-04) has been announced as one of EL CVn candidates showing total primary eclipses and ellipsoidal variations. This paper presents the absolute properties of the binary star, based on our high-resolution…
Using data from the extended Kepler mission in K2 Campaign 10 we identify two eclipsing binaries containing white dwarfs with cool companions that have extremely short orbital periods of only 71.2 min (SDSS J1205-0242, a.k.a. EPIC…
We present the discovery of the eclipsing double white dwarf (WD) binary WDJ 022558.21-692025.38 that has an orbital period of 47.19 min. Following identification with the Transiting Exoplanet Survey Satellite, we obtained time-series…
Cool subdwarfs are metal-poor low-mass stars that formed during the early stages of the evolution of our Galaxy. Because they are relatively rare in the vicinity of the Sun, we know of few cool subdwarfs in the solar neighbourhood, and none…
We report the discovery of the first hot subdwarf B (sdB) star with a massive compact companion in a wide ($P=892.5\pm60.2\,{\rm d}$) binary system. It was discovered based on an astrometric binary solution provided by the Gaia mission Data…
Hot subdwarfs are considered to be the compact helium cores of red giants, which lost almost their entire hydrogen envelope. What causes this enormous mass loss is still unclear. Binary interactions are invoked and a significant fraction of…
We present high-speed ULTRACAM and SOFI photometry and X-shooter spectroscopy of the recently discovered 94 minute orbital period eclipsing white dwarf / main-sequence binary SDSS J085746.18+034255.3 (CSS 03170) and use these observations…
SDSS J030308.35+005444.1 is a close, detached, eclipsing white dwarf plus M dwarf binary which shows a large infrared excess which has been interpreted in terms of a circumbinary dust disk. In this paper we present optical and near-infrared…
We report the discovery of an extremely close, eclipsing binary system. A white dwarf is orbited by a core He-burning compact hot subdwarf star with a period as short as $\simeq0.04987 {\rm d}$ making this system the most compact hot…
Astronomers have discovered thousands of planets outside the solar system, most of which orbit stars that will eventually evolve into red giants and then into white dwarfs. During the red giant phase, any close-orbiting planets will be…
We report the discovery of two new hot, hydrogen-rich subdwarfs (sdB) in close binary systems. The hot subdwarfs, GALEX J0321+4727 and GALEX J2349+3844, were selected from a joint optical-ultraviolet catalogue of hot sub-luminous stars…
Our discovery of 1SWASP J093010.78+533859.5 as a probable doubly eclipsing quadruple system containing a contact binary with P~0.23 d and a detached binary with P~1.31 d was announced in 2013. Subsequently Koo et al. confirmed the detached…
We report the discovery by the WASP transit survey of a giant planet in a close orbit (0.0295+-0.0009 AU) around a moderately bright (V=11.6, K=10) G9 dwarf (0.89+-0.08 M_sun, 0.84+-0.03 R_sun) in the Southern constellation Eridanus. Thanks…
There is a striking and unexplained dearth of brown dwarf companions in close orbits (< 3AU) around stars more massive than the Sun, in stark contrast to the frequency of stellar and planetary companions. Although rare and relatively…
We present EVR-CB-001, the discovery of a compact binary with an extremely low mass ($.21 \pm 0.05 M_{\odot}$) helium core white dwarf progenitor (pre-He WD) and an unseen low mass ($.32 \pm 0.06 M_{\odot}$) helium white dwarf (He WD)…
Hot subdwarf (SD) stars are the stripped cores of red giant stars in transition to the white dwarf sequence. The B-type subdwarfs (sdB) are powered by helium fusion in the core, more evolved ones (sdO) by shell burning. Low mass SDs may…
We have measured the orbital parameters of seven close binaries, including six new objects, in a radial velocity survey of 38 objects comprising a hot subdwarf star with orbital periods ranging from ~0.17 to 3 d. One new system, GALEX…
Understanding interactions of binary systems on the red giant branch is crucial to understanding the formation of compact stellar remnants such as helium-core white dwarfs (He-WDs) and hot subdwarfs. However, the detailed evolution of such…
Context. Though only a handful of extrasolar planets have been discovered via direct imaging, each of these discoveries had tremendous impact on our understanding of planetary formation, stellar formation and cool atmosphere physics. Aims.…