Barycentric Corrections at 1 cm s-1 for Precise Doppler Velocities

By J. Wright, Jason Eastman. 2014

144 citations recorded by the source corpus.

The goal of this paper is to establish the requirements of a barycentric correction with an rms of ≲1 cm s-1, which is an order of magnitude better than necessary for the Doppler detection of true Earth analogs (∼9 cm s-1). We describe the theory and implementation of accounting for the effects on precise Doppler measurements of motion of the telescope through space, primarily from rotational and orbital motion of the Earth, and the motion of the solar system with respect to target star (i.e., the “barycentric correction”). We describe the minimal algorithm necessary to accomplish this and how it differs from a naïve subtraction of velocities (i.e., a Galilean transformation). We demonstrate the validity of code we have developed from the California Planet Survey code via comparison with the pulsar timing package, TEMPO2. We estimate the magnitude of various terms and effects, including relativistic effects, and the errors associated with incomplete knowledge of telescope position, timing, and stellar position and motion. We note that chromatic aberration will create uncertainties in the time of observation, which will complicate efforts to detect true Earth analogs. Our code is available for public use and validation.

Subfields: Astronomy and Astrophysics, Oceanography

View Paper: https://www.semanticscholar.org/paper/d94c006bcc33d44d88c14e56080f5a67183d472c

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

EXTRACTING RADIAL VELOCITIES OF A- AND B-TYPE STARS FROM ECHELLE SPECTROGRAPH CALIBRATION SPECTRA (2015, background): “We do not correct for the gravitational redshift due to either the host star or our own sun, as those effects would be on the order of a few m s−1, which is well below our target precision (Wright & Eastman 2014).”
Spectrum radial velocity analyser (SERVAL). High-precision radial velocities and two alternative spectral indicators (2017, methodology): “For ultimate precision in the barycentric correction, the code from Wright & Eastman (2014) with 1 cm/s accuracy can be used instead, which includes relativistic corrections3.”
State of the Field: Extreme Precision Radial Velocities (2016, background): “…for the velocity of the Earth must be applied in order to recover precise radial velocity measurements of stars for exoplanet detection.92 Wright & Eastman (2014) outline the magnitude of error contributions to the barycentric velocity correction, including rotational and orbital motion…”
The CARMENES search for exoplanets around M dwarfs (2018, background): “They are corrected for barycentric motion (Wright & Eastman 2014), as well as for secular acceleration, which is important for stars with high proper motions (Zechmeister et al. 2009).”