Jul 19, 2018

Masses, Orbits, and Merger Rates of Double White Dwarfs


Measuring the orbits of double white dwarfs. @_sublunar_

Follow-up of interesting binaries and high-order multiple systems uncovered with the Gaia-ESO Survey


Stellar multiplicity is ubiquitous in galaxies because stars are born in clusters or associations rather than in an isolated way. Around 50% of stars similar to the Sun have companions and this fraction increases for high mass stars. Multiple stellar systems, when detected by the radial velocity method using spectrographs, are called spectroscopic binaries.This program is dedicated to the follow-up of the most interesting spectroscopic binaries discovered within the Gaia-ESO Survey. It will provide a better insight on stellar multiplicity (and the way stars form in groups) as well as on stellar evolution and interaction between closeby companions.

Symbiotic stars – important tracers of late evolutionary stages III


We propose a large spectroscopic monitoring of a sample of Magellanic symbiotic stars composed of cold red giant stars and hot white dwarfs, which challenge the binary star evolution models because they do not predict their existence. Our proposed observations will allow us to measure the masses of the two stars in the binary system. They will also help us to understand the formation and evolution of these theoretically impossible although existing binaries.

Spectral monitoring of a new class of high mass interacting binaries


A new class of hot, giant stars interacting with a “dead star” companion has been recently discovered. We are monitoring these intriguing “monster binaries” with SALT, to find out whether they may one day explode assupernovae, or whether they host a black hole.

Systematic radial velocity monitoring of likely intermediate period post-AGB binaries


We are searching for binary stars in some of the most beautiful stellar remnants in the Galaxy.

Detailled study of CEMP stars identified in the RAVE survey


We are observing around 120 stars that are among the oldest in our Galaxy. Determining their chemical composition will allow us to understand what happened during the first billion years of the Universe

Spectroscopic observations of central stars of mid-infrared nebulae discovered w ith Spitzer and WISE


Spectroscopic observations of central stars of mid-infrared nebulae discovered with Spitzer and WISE

Identification of Lensing Objects by Real-time Spectroscopy of Microlensing Events


A “source” star can appear to brighten when a massive “lens” object passes between us and the source. We hope to identify the lens with real-time SALT spectroscopy of such “gravitational microlensing events,” and someday use the methods we develop to discover isolated black holes

Observing the Transient Universe


This large SALT program is aimed at studying “things that go bang in the night”, namely transient objects in the Universe which either are newly discovered objects, or known objects who suddenly change their appeatance. Such things include binary stars with accreting compact companions, many of them X-ray or gamma ray sources, eruptive stars which suddenly brighten, black holes systems, including active galaxies powered by them, and all manner of explosions including the most energetic of all, gamma ray bursts.

Jul 18, 2018

Characterising the host star and protoplanetary disk environment in nearby young star systems


The young star β Pictoris is seen orbited by a warped edge-on debris disc of gas and dust, as well as a massive planet. In order to gain insights into the mechanisms of planetary system formation, it is useful to study the properties, behaviour and interaction of exocomets within this and other similar young planetary system.