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

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 radial velocity (RV) precision of up to 2 m s −1 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 10 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 M Jup 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.

SPOTS: The Search for Planets Orbiting Two Stars

“…It has been suggested that at least some of these planets might have formed as second-generation planets from ejected stellar material after the common-envelope phase (Perets 2010). Efforts are also made to search for circumbinary planets with Doppler spectroscopy (Konacki et al 2009). …”

Binaries Among Debris Disk Stars

“…The problem is that the spectra of close binary stars are highly variable due to their orbital motion which typically leads to relatively large velocity uncertainties. However, the TATOOINE radial velocity survey (Konacki et al 2009) is searching for planets around double-lined spectroscopic binaries and has reached precisions of a few m s −1 , comparable to, albeit not as good as, precisions reached for single stars. Although Konacki et al (2009) have yet to report a circumbinary planet and their sample size is small (10 systems), their work demonstrates that future planet searches may be performed on close binaries.…”

“…However, the TATOOINE radial velocity survey (Konacki et al 2009) is searching for planets around double-lined spectroscopic binaries and has reached precisions of a few m s −1 , comparable to, albeit not as good as, precisions reached for single stars. Although Konacki et al (2009) have yet to report a circumbinary planet and their sample size is small (10 systems), their work demonstrates that future planet searches may be performed on close binaries. Duquennoy & Mayor (1991) estimate that 57% of G stars may be in multiple systems.…”

“…Eclipse timing variations of HW Virginis, CM Draconis, and NN Serpentis (a post-common envelope binary) suggest that planets may orbit these binaries (Deeg et al 2008;Lee et al 2009;Beuermann et al 2010). Despite these efforts (see also Konacki et al 2009), detection of planets in circumbinary orbits remains a challenge. While this manuscript was being prepared, Doyle et al (2011) presented the discovery of Kepler-16b, the first circumbinary planet among the Kepler data.…”

The Dwarf project: Eclipsing binaries – precise clocks to discover exoplanets

“…Three principal techniques are: (i) precise radialvelocity (hereafter RV) measurements to detect the wobble of the binary mass center (Konacki et al 2009), (ii) photometric detection of transits of the planet(s) across the disks of the components of the inner binary (Doyle et al 2011), and (iii) timing of the inner binary eclipses (Lee et al 2009). …”