The HATSouth Exoplanet Survey

We detect exoplanets by monitoring large parts of the sky and attempting to determine if the light from a star periodically dims for a short time. This short "dip" in the light received may be due to a small planetary-sized object moving in its orbit in front of the star as seen from our vantage point on Earth. This is a so-called exoplanet transit signal. The length and shape of this transit signal is related to the radius and orbital period of the object passing in front of the star. Extensive follow-up observations are usually carried out to determine if the object detected in this way has a radius and mass consistent with that of a planet. Exoplanet detection by this method has proven to be enormously successful, and is responsible for a large fraction of all discovered exoplanets over the past twenty years.

HATSouth telescope systems are located at the Las Campanas Observatory (LCO) in Chile, at the High Energy Stereoscopic System (HESS) site in Namibia, and at the Siding Spring Observatory (SSO) in Australia. Each site has two HATSouth stations; each station consists of four 180-mm f/2.8 Takahashi astrographs attached to large-format CCD cameras, accompanied by purpose-built heavy-duty mounts and dome enclosures. All operations are automated; the HATSouth stations make autonomous decisions about when and what to observe based on weather conditions and pre-programmed observing priorities.

The large separation in longitude of the HATSouth sites allows us to seamlessly monitor the sky over the better part of 24 hours, reducing our susceptibility to false-positive exoplanet transit signals caused by interruptions in observing. This is especially advantageous during the Southern summer months, when a target star field can be observed in a continuous relay by telescopes at all three sites. During the Southern winter, a target star field will still be observed by telescopes at two sites near-continuously, thus ensuring dense coverage year-round.