Las Campanas Observations: Winter Solstice 2018

By: David Osip and Javiera Rey

Exoplanets across LCO

The discovery and characterization of planets beyond our own Solar System, called exoplanetsis an area of study that allows the people and facilities at Las Campanas Observatory to demonstrate their spectacular ability to work together for a common cause. 

Photo of Magellan telescopes on mountain with blooming flowers in the foreground

Exoplanet discovery observations are taking place from our smallest (0.18-meter) to our largest (6.5-meter) aperture telescopes. The HATSouth project, in operation since 2009, uses three observing stations spread around the southern hemisphere, one located at LCO, to continuously observe regions of the sky and to look for evidence of a transiting planet briefly shadowing a fraction of a bright star’s stellar light. 


The Carnegie Astrometric Planet Search Camera (CAPSCam), operating since 2007, is deployed at the du Pont 2.5-meter telescope in an ongoing campaign to detect exoplanets by measuring their gravitational effect on the host star, which causes a measurable wobble in the position of the star. 


Operating on the Magellan Clay telescope since 2010, the Planet Finder Spectrograph (PFS) uses high-resolution spectra to measure radial velocities of stars to an exquisite precision of better than one meter per second.  The periodic variation of these stellar velocities can reveal the presence of a planet—sometimes more than one—orbiting their host star and be used to determine its mass and orbit.  


These same facilities are also regularly used to verify and characterize the properties of discovered exoplanets that were discovered elsewhere. High-precision measurements of changes in a star’s luminosity to confirm the existence transiting exoplanets are sometimes done by the Swope 1-meter telescope.  Our most-recently commissioned telescope at LCO, the CHAT 0.7-meter, is dedicated to similar high-precision brightness measurements to find transiting exoplanets and candidates from HATSouth. The Magellan telescopes allow even more-detailed investigations of exoplanet atmospheres based on transmission spectroscopy taken during transits with the IMACS and LDSS3 spectrographs, as well as with high-resolution spectral line analysis of Doppler shifted spectra observed with PFS and the MIKE echelle spectrographs.  


It is when working as a team that LCO’s suite of telescopes and instruments best allows its scientists to search for and elucidate the true nature of exoplanets. Who knows? Maybe one day Earth’s twin will be found at LCO! 


[Top image left courtesty Gaspar Bakos/HATSouth. Top image right courtesy PFS team. Bottom images both courtesy of Yuri Beletsky