Extrasolar Planet Research at the LSW

Radial Velocities

From 1999 to 2012 we carried out a precise radial velocity survey of a sample of 373 G and K giant stars, using the Hamilton High Resolution Spectrograph in conjunction with an iodine cell and the 60cm CAT Telescope at Lick Observatory. The goal was and still is to search for substellar companions (extrasolar planets and brown dwarfs) in this sample, and to compare the properties of the identified substellar companions to those found around main-sequence stars in order to investigate the effect of primary star mass and stellar evolution. A particular emphasis more recently has been on the dynamical simulation of systems containing several stellar or planetary companions.

Waltz Spectrograph

In 2012, observing at Lick stopped, one of the reasons being that the iodine cell was damaged. A new cell would introduce a radial velocity offset. We are taking the opportunity to built a high resolution spectrograph for the 70cm Waltz Telescope on the Königstuhl in Heidelberg, where we plan to continue observing our Lick giants stars in the future. The Waltz Spectrograph will also be used for student education, and we are thrilled to combine science and education by offering our students night time observing experience.


We are also heavily involved in the CARMENES project, a german-spanish collaboration which carries out a precise Doppler survey of about 300 M dwarfs at the 3.5m telescope at Calar Alto (Spain) since 2016. The goal of the CARMENES survey is to find low-mass planets orbiting in the habitable zones of their host stars. The CARMENES instrument consists of two spectrographs which cover the visible and the near infrared wavelength regimes simultaneously. The visual spectrograph reaches a precision of around 1 m/s.

Direct Imaging

The LSW is part of an international consortium which performs a direct imaging survey for planets in wide orbits around nearby young stars using the NaCo instrument at one of ESO's VLT Telescopes in Chile. The survey runs from 2015 to 2019, with about 120 guaranteed nights in total. Originally, the plan was to carry out an astrometric survey for planets around nearby stars with the PRIMA instruments, but those efforts were terminated in 2014.


We are looking forward to use Gaia Data for our Exoplanet Research!

In the past, we have used the Intermediate Astrometric Data provided by Hipparcos to place upper limits on the masses of planets and brown dwarfs detected with the Doppler method. We could confirm nine planets and two brown dwarfs. For 20 systems, we could detect the astrometric signature of the companion in the Hipparcos data, yielding constraints on inclination and ascending node (Reffert & Quirrenbach 2011, A&A 527, A140).

last updated: Dec 19, 2023, by Sabine Reffert