J/AJ/153/208 LCES HIRES/Keck radial velocity Exoplanet Survey (Butler+, 2017)
The LCES HIRES/Keck precision radial velocity Exoplanet Survey.
Butler R.P., Vogt S.S., Laughlin G., Burt J.A., Rivera E.J., Tuomi M.,
Teske J., Arriagada P., Diaz M., Holden B., Keiser S.
<Astron. J., 153, 208-208 (2017)>
=2017AJ....153..208B 2017AJ....153..208B (SIMBAD/NED BibCode)
ADC_Keywords: Planets ; Stars, nearby ; Stars, dwarfs ; Radial velocities ;
Keywords: planetary systems
Abstract:
We describe a 20 year survey carried out by the Lick-Carnegie
Exoplanet Survey Team (LCES), using precision radial velocities from
HIRES on the Keck I telescope to find and characterize extrasolar
planetary systems orbiting nearby F, G, K, and M dwarf stars. We
provide here 60949 precision radial velocities for 1624 stars
contained in that survey. We tabulate a list of 357 significant
periodic signals that are of constant period and phase, and not
coincident in period and/or phase with stellar activity indices. These
signals are thus strongly suggestive of barycentric reflex motion of
the star induced by one or more candidate exoplanets in Keplerian
motion about the host star. Of these signals, 225 have already been
published as planet claims, 60 are classified as significant
unpublished planet candidates that await photometric follow-up to rule
out activity-related causes, and 54 are also unpublished, but are
classified as "significant" signals that require confirmation by
additional data before rising to classification as planet candidates.
Of particular interest is our detection of a candidate planet with
Msin(i)=3.8M⊕, and P=9.9 days orbiting Lalande 21185, the
fourth-closest main-sequence star to the Sun. For each of our
exoplanetary candidate signals, we provide the period and
semi-amplitude of the Keplerian orbital fit, and a likelihood ratio
estimate of its statistical significance. We also tabulate 18
Keplerian-like signals that we classify as likely arising from stellar
activity.
Description:
We present 60949 precision radial velocities of 1624 stars obtained
over the past 20 years from the Lick-Carnegie Exoplanet Survey Team
(LCES) survey with the HIgh-Resolution Echelle Spectrometer (HIRES)
spectrometer on the Keck I telescope. We tabulate a list of 357
significant periodic signals that are of constant period and phase,
and not coincident in period and/or phase with stellar activity
indices.
For this survey, the HIRES spectrometer was configured to operate at a
nominal spectral resolving power of R∼60000 and wavelength range of
3700-8000Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
targets.dat 14 1680 Stars observed (corrected velocities in Tal-Or
et al, 2019, Cat. J/MNRAS/484/L8)
table1.dat 74 62913 Radial velocities and chromospheric activity
indices of all program stars
(corrected velocities in Tal-Or
et al, 2019, Cat. J/MNRAS/484/L8)
table2.dat 73 357 *Signals in the Keck data sets
table3.dat 84 1010 Maximum likelihood parameter estimates and
standard errors for the "nuisance" parameters
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Note on table2.dat: With likelihood ratio ΔlnLj=lnL(j=k)-lnL(j=k-1)
between models with k and k-1 signals for which the ratio exceeds a value
corresponding to a 0.1% False Alarm Probability (FAP) threshold of a
three-parameter model (amplitude K, period P, and phase Φ).
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See also:
J/A+A/566/A66 : Correlation of logR'HK with logIHa (Gomes da Silva+, 2014)
J/A+A/551/A79 : RV periodic variations in τ Ceti (Tuomi+, 2013)
J/ApJ/646/505 : Catalog of nearby exoplanets (Butler+, 2006)
J/ApJ/634/625 : Radial velocities and photometry of GJ 876 (Rivera+, 2005)
J/MNRAS/484/L8 : Correcting HIRES/Keck RVs for systematic errors (Tal-Or+, 2019)
Byte-by-byte Description of file: targets.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Target identifier
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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- 38 F9.2 m/s RV [-39874.3/42363.6] Radial velocity
40- 45 F6.2 m/s e_RV [0.01/252.9] 1σ uncertainty in RV
47- 53 F7.4 --- S [-5.5/68.9] Chromosperic activity index S-index (1)
55- 62 F8.5 --- H [-1/0.11]? Chromosperic activity index H-index (2)
64- 69 I6 --- Count [67/616935] Median photons per pixel
71- 74 I4 s Exp [-1/2551] Exposure time
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Note (1): Obtained from measurement of the emission reversal at the cores of the
Fraunhofer H and K lines of Ca II at 3968Å and 3934Å respectively.
Note (2): A measure of the chromospheric emission component at the Hα
Balmer line of hydrogen at 6563Å (Gomes da Silva et al.
2011A&A...534A..30G 2011A&A...534A..30G). Note that H-index values H≥0.062 are to be
considered with caution (see Section 4 in the paper).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Num [4/1672] Target number
6- 15 A10 --- Name Target identifier
17 I1 --- Ns [1/4] Number of signals (nsignals)
19- 24 F6.2 [-] LR [16.5/673.3] Likelihood ratio (ΔlnLk)
26- 35 F10.5 d Per [1/6264.7] Period
37- 45 F9.5 d e_Per [0/573.77] Uncertainty in Per
47- 52 F6.2 m/s K [1.25/840.71] Radial velocity amplitude
54- 59 F6.2 m/s e_K [0.17/165.1] Uncertainty in K
61- 69 A9 --- Signal Interpretation (either Activity, Candidate,
Published, or SRC=Signal Requiring
Confirmation) (1)
71- 73 A3 --- Note Additional note (1-7) (2)
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Note (1): The signals are classified as follows:
Published = Signal that have already been published as planet claim;
Candidate = Significant unpublished planet candidate that await
photometric follow-up to rule out activity-related cause;
SRC = Signal Requiring Confirmation by additional data before rising
to classification as planet candidate;
Activity = Keplerian-like signal that we classify as likely arising from
stellar activity.
Note (2): Additional notes are defined as follows:
1 = Signal coincides with a photometric rotation period based on ASAS
V-band photometry;
2 = Corresponding signal in the S-index data at a very nearby period likely
indicative of the rotation period of the star;
3 = Signal not constrained from above in the parameter space as the
analyses were limited to 1 day<P<Tobs;
4 = Coincides with the stellar magnetic cycle apparent in the S-index but
strong enough as a signal to be interpreted as a candidate planet;
5 = Likely artifact signal caused by orbital evolution of the system;
6 = Daily alias of the known transiting planet orbiting the star with an
orbital period of 0.73 days (Winn et al. 2011ApJ...737L..18W 2011ApJ...737L..18W);
7 = The strongest S-index counterpart in our sample indicates this signal
is likely caused by activity unless one argues that S-index variability
cannot have counterparts in radial velocities. Signal reported as a
planet candidate.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Num [3/1673] Target number
6- 19 A14 --- Name Target identifier
21- 28 F8.3 m/s/yr dV/dt [-900.31/622.51] Linear acceleration γ
30- 36 F7.3 m/s/yr e_dV/dt [0.035/332.111] Standard error in dV/dt
38- 42 F5.2 m/s sigmaJ [0.32/98.7] Excess white noise or "jitter"
(σJ)
44- 48 F5.2 m/s e_sigmaJ [0.07/20.31] Standard error in sigmaJ
50- 58 F9.3 m/s cS [-4866.9/8437.7] Coefficient quantifying
linear dependence of the radial velocities
on the S-index (cS)
60- 67 F8.3 m/s e_cS [0.18/4622.1] Standard error in cS
69- 75 F7.3 [-] LRS [7.883/159.22]?=0 Likelihood ratio statistic
ΔlnLS (1)
77- 84 F8.3 d Per [2.065/6308.8]?=0 Period of the signal in the
S-index time-series (PS)
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Note (1): ΔlnLS=lnLS(k=1)-lnLS(k=0) represents the likelihood ratio
statistic of model with a signal (k=1) in the S-index with respect to a
model without a signal (k=0). Only signals exceeding a ratio of 7.82
corresponding to 5% False Alarm Probability (FAP) are shown.
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 07-Aug-2017