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Published June 27, 2017 | Submitted
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Precise Radial Velocities of 2046 Nearby FGKM Stars and 131 Standards

Abstract

We present radial velocities with an accuracy of 0.1 km/s for 2046 stars of spectral type F,G,K, and M, based on 29000 spectra taken with the Keck I telescope. We also present 131 FGKM standard stars, all of which exhibit constant radial velocity for at least 10 years, with an RMS less than 0.03 km/s. All velocities are measured relative to the solar system barycenter. Spectra of the Sun and of asteroids pin the zero-point of our velocities, yielding a velocity accuracy of 0.01 km/s for G2V stars. This velocity zero-point agrees within 0.01 \kms with the zero-points carefully determined by Nidever et al. (2002) and Latham et al. (2002). For reference we compute the differences in velocity zero-points between our velocities and standard stars of the IAU, the Harvard-Smithsonian Center for Astrophysics, and l'Observatoire de Geneve, finding agreement with all of them at the level of 0.1 km/s. But our radial velocities (and those of all other groups) contain no corrections for convective blueshift or gravitational redshifts (except for G2V stars), leaving them vulnerable to systematic errors of 0.2 \kms for K dwarfs and ~0.3 km/s for M dwarfs due to subphotospheric convection, for which we offer velocity corrections. The velocities here thus represent accurately the radial component of each star's velocity vector. The radial velocity standards presented here are designed to be useful as fundamental standards in astronomy. They may be useful for Gaia (Crifo et al. 2010, Gilmore et al. 2012} and for dynamical studies of such systems as long-period binary stars, star clusters, Galactic structure, and nearby galaxies, as will be carried out by SDSS, RAVE, APOGEE, SkyMapper, HERMES, and LSST.

Additional Information

Submitted on 26 Jul 2012 (v1), last revised 1 Aug 2012 (this version, v2). We are indebted to the University of California and NASA for allocation of telescope time on the Keck telescope. We thank Charles Francis and Erik Anderson for a critical review of the velocities compared to past measurements. We thank Guillermo (Willie) Torres and Dimitri Pourbaix for valuable suggestions that improved the manuscript. This work benefited from valuable discussions about radial velocity standard stars with Dave Latham, Stephane Udry, and Dainis Dravins. We are grateful to UCLA for hospitality during the writing of some of the paper. This work made use of the Exoplanet Orbit Database and the Exoplanet Data Explorer at www.exoplanets.org. All 29000 spectra are archived and publicly available, thanks to the Keck Observatory Archive made possible by a NASA-funded collaboration between the NASA Exoplanet Science Institute and the W. M. Keck Observatory. We acknowledge support by NASA grants NAG5-8299, NNX11AK04A, NSF grants AST95-20443 (to GWM) and AST-1109727 (to JTW), and by Sun Microsystems. This research was made possible by the generous support from the Watson and Marilyn Albert SETI Chair fund (to GWM) and by generous donations from Howard and Astrid Preston. The Center for Exoplanets and Habitable Worlds is supported by the Pennsylvania State University, the Eberly College of Science, and the Pennsylvania Space Grant Consortium. This research has made use of NASA's Astrophysics Data System and the SIMBAD database, operated at CDS, Strasbourg, France. We thank R.Paul Butler and Steven Vogt for help making observations. We thank the staff of the W.M Keck Observatory and Lick Observatory for their valuable work maintaining and improving the telescopes and instruments, without which the observations would not be possible. We appreciate the State of California for its support of operations at both observatories. We thank the University of California, Caltech, the W.M. Keck Foundation, and NASA for support that made the Keck Observatory possible. We appreciate the indigenous Hawaiian people for the use of their sacred mountain, Mauna Kea.

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Additional details

Created:
August 19, 2023
Modified:
October 26, 2023