The Radial Velocity TATOOINE Search for Circumbinary Planets: Planet Detection Limits for a Sample of Double-lined Binary Stars - Initial Results from Keck I/Hires, Shane/CAT/Hamspec and TNG/Sarg Observations

TL;DR

This paper reports a novel high-precision radial velocity technique applied to a small sample of double-lined binary stars, enabling the detection of circumbinary planets with masses down to a few Jupiter masses within five-year periods.

Contribution

It introduces a new radial velocity method with 2 m/s precision for double-lined binaries and demonstrates its capability to set planet detection limits.

Findings

Achieved 2 m/s RV precision with iodine cell technique.

Ruled out planets >0.3-3 MJup within 5.3-year orbits for the sample.

Demonstrated the feasibility of circumbinary planet searches with current methods.

Abstract

We present preliminary results of the first and on-going radial velocity survey for circumbinary planets. With a novel radial velocity technique employing an iodine absorption cell we achieve an unprecedented RV precision of up to 2 m/s for double-lined binary stars. The high resolution spectra collected with the Keck I/Hires, TNG/Sarg and Shane/CAT/Hamspec telescopes/spectrographs over the years 2003-2008 allow us to derive RVs and compute planet detection limits for ten double-lined binary stars. For this initial sample of targets, we can rule out planets on dynamically stable orbits with masses as small as ~0.3 to 3 MJup for the orbital periods of up to ~5.3 years. Even though the presented sample of stars is too small to make any strong conclusions, it is clear that the search for circumbinary planets is now technique-wise possible and eventually will provide new constraints for the planet formation theories.