The KOBE experiment: K-dwarfs Orbited By habitable Exoplanets. Project goals, target selection and stellar characterization

Abstract

The detection of habitable worlds is one of humanity's greatest endeavors. So far, astrobiological studies show that one of the most critical components for life development is liquid water. Its chemical properties and its capacity to dissolve and hence transport other substances makes this constituent a key piece in the development of life. As a consequence, looking for life as we know it is directly related to the search for liquid water. For a remote detection of life in distant planetary systems, this means looking for planets in the so-called habitable zone. In this sense, K-dwarf stars are the perfect hosts. Contrary to G-dwarfs, the habitable zone is closer, thus making planet detection easier using transit or radial velocity techniques. Contrary to M-dwarfs, the stellar activity is much smaller, hence having a smaller impact in both the detectability and in the true habitability of the planet. Also, K-dwarfs are the quietest in terms of oscillations, and granulation noise. Despite this, there is a dearth of planets in the habitable zone of K-dwarfs due to a lack of observing programs devoted to this parameter space. In response to a call for Legacy Programs of the Calar Alto observatory, we have started the first dedicated and systematic search for habitable planets around K-dwarfs, the K-dwarfs Orbited By habitable Exoplanets (KOBE). This survey is monitoring the radial velocity of 50 carefully pre-selected K-dwarfs with the CARMENES instrument along 5 semesters with an average of 90 data points per target. Based on planet occurrence rates convolved with our detectability limits, we expect to find $1.68\pm 0.25$ planets per star in the KOBE sample and in half of the sample we expect to find one of those planets within the habitable zone. In this paper, we describe the project motivation, goals and target selection and preliminary stellar characterization.

Accepted for publication in A&A. 12 pages, 9 figures, 1 table. Language corrected

References in corpus (28)

• Array Programming with NumPy
• The Gaia mission
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• Extreme Water Loss and Abiotic O${}_2$ Buildup On Planets Throughout the Habitable Zones of M Dwarfs
• The Kepler Catalog of Stellar Flares
• Trumpeting M Dwarfs with CONCH-SHELL: a Catalog of Nearby Cool Host-Stars for Habitable ExopLanets and Life
• Tidal Locking of Habitable Exoplanets
• Magnetic activity in the HARPS M-dwarf sample. The rotation-activity relationship for very low-mass stars through R'HK
• A nearby M star with three transiting super-Earths discovered by K2
• The CARMENES search for exoplanets around M dwarfs -- Planet occurrence rates from a subsample of 71 stars
• High-resolution imaging of $Kepler$ planet host candidates. A comprehensive comparison of different techniques
• Validation of Twelve Small Kepler Transiting Planets in the Habitable Zone
• A candidate short-period sub-Earth orbiting Proxima Centauri
• Searching the Entirety of Kepler Data. II. Occurrence Rate Estimates for FGK Stars
• Revisiting Proxima with ESPRESSO
• The CARMENES search for exoplanets around M dwarfs. Stellar atmospheric parameters of target stars with SteParSyn
• Warm terrestrial planet with half the mass of Venus transiting a nearby star
• A Preponderance of Perpendicular Planets
• An Exomoon Survey of 70 Cool Giant Exoplanets and the New Candidate Kepler-1708 b-i
• About Exobiology: The Case for Dwarf K Stars
• A precise architecture characterization of the $\pi$ Men planetary system
• The K Dwarf Advantage for Biosignatures on Directly Imaged Exoplanets
• The TROY project: Searching for co-orbital bodies to known planets. I. Project goals and first results from archival radial velocity
• HAZMAT. V. The Ultraviolet and X-ray Evolution of K Stars
• The Impact of Stellar Surface Magnetoconvection and Oscillations on the Detection of Temperate, Earth-Mass Planets Around Sun-Like Stars
• The CARMENES search for exoplanets around M dwarfs: Not-so-fine hyperfine-split vanadium lines in cool star spectra
• Characterization of Exoplanet-Host Stars

Cited by in corpus (12)

• An unusually low-density super-Earth transiting the bright early-type M-dwarf GJ 1018 (TOI-244)
• TOI-5005 b: A super-Neptune in the savanna near the ridge
• The ultraviolet habitable zone of exoplanets
• Two super-Earths at the edge of the habitable zone of the nearby M dwarf TOI-2095
• TOI-969: a late-K dwarf with a hot mini-Neptune in the desert and an eccentric cold Jupiter
• Large Interferometer For Exoplanets (LIFE). X. Detectability of currently known exoplanets and synergies with future IR/O/UV reflected-starlight imaging missions
• Expanding the frontiers of cool-dwarf asteroseismology with ESPRESSO. Detection of solar-like oscillations in the K5 dwarf $\epsilon$ Indi
• KOBE-1: The first planetary system from the KOBE survey. Two planets likely residing in the sub-Neptune mass regime around a late K-dwarf
• The star HIP 41378 potentially misaligned with its cohort of long-period planets
• K2-399 b is not a planet. The Saturn that wandered through the Neptune desert is actually a hierarchical eclipsing binary
• Discovery of a transiting hot water-world candidate orbiting Ross 176 with TESS and CARMENES
• $\mathtt{KOBEsim}$: a Bayesian observing strategy algorithm for planet detection in radial velocity blind-search surveys