J/MNRAS/484/L8 Correcting HIRES/Keck RVs for systematic errors (Tal-Or+, 2019)
Correcting HIRES/Keck radial velocities for small systematic errors.
Tal-Or L., Trifonov T., Zucker S., Mazeh T., Zechmeister M.
<Mon. Not. R. Astron. Soc. 484, L8-L13 (2019)>
=2019MNRAS.484L...8T 2019MNRAS.484L...8T (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Radial velocities
Keywords: instrumentation: spectrographs - techniques: radial velocities -
planetary systems
Abstract:
The HIRES spectrograph, mounted on the 10-m Keck-I telescope, belongs
to a small group of radial-velocity (RV) instruments that produce
stellar RVs with long-term precision down to ∼1m/s. In 2017, the
HIRES team published 64480 RVs of 1699 stars, collected between 1996
and 2014. In this bank of RVs, we identify a sample of RV-quiet stars,
whose RV scatter is <10m/s, and use them to reveal two small but
significant nightly zero-point effects: a discontinuous jump, caused
by major modifications of the instrument in August 2004, and a
long-term drift. The size of the 2004 jump is 1.5±0.1m/s, and the
slow zero-point variations have a typical magnitude of <1m/s. In
addition, we find a small but significant correlation between stellar
RVs and the time relative to local midnight, indicative of an average
intranight drift of 0.051±0.004m/s/h. We correct the 64480 HIRES
RVs for the systematic effects we find, and make the corrected RVs
publicly available. Our findings demonstrate the importance of
observing RV-quiet stars, even in the era of simultaneously-calibrated
RV spectrographs. We hope that the corrected HIRES RVs will facilitate
the search for new planet candidates around the observed stars.
Description:
The catalogue contains the data presented in Table 1 of the source
paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 62 1699 List of studied stars
table1.dat 88 64480 Radial velocities of 1699 stars from Butler et al.,
2017, J/AJ/153/208, corrected for
small systematic errors
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See also:
J/AJ/153/208 : LCES HIRES/Keck radial velocity Exoplanet Survey (Butler+, 2017)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Target identifier
16- 17 I2 h RAh ? Right ascension (J2000)
19- 20 I2 min RAm ? Right ascension (J2000)
22- 26 F5.2 s RAs ? Right ascension (J2000)
28 A1 --- DE- Declination sign (J2000)
29- 30 I2 deg DEd ? Declination (J2000)
32- 33 I2 arcmin DEm ? Declination (J2000)
35- 38 F4.1 arcsec DEs ? Declination (J2000)
41- 44 I4 --- Nobs [2/813] Number of observations in table1.dat
47- 66 A20 --- SName Simbad name
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Target identifier
16- 28 F13.5 d BJD Barycentric Julian Date
30- 39 F10.3 m/s RVcor [-39874/42364] Corrected radial velocity
41- 47 F7.3 m/s e_RVcor [0.01/374] 1σ uncertainty in RVel
49- 55 F7.4 --- S [-5.5/69] Chromosperic activity S-index (1)
57- 63 F7.4 --- H [-1/0.11]?=-1 Chromosperic activity H-index (2)
65- 70 I6 --- Count [67/616935] Median photons per pixel
72- 75 I4 s ExpTime [-1/2551] Exposure time
77- 82 F6.3 m/s CorV [-39874/42364] Radial velocity correction value
84- 88 F5.3 m/s e_CorV [0.01/253] 1σ uncertainty in CorV
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Note (1): A measure of the chromospheric emission at the Ca II H and K lines.
Note (2): A measure of the chromospheric emission at the Hα Balmer line.
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Acknowledgements:
Lev Tal-Or, School of Geosciences, Tel Aviv University
levtalo(at)post.tau.ac.il
(End) L. Tal-Or [School of Geosciences, Tel Aviv], P. Vannier [CDS] 05-Dec-2018