J/AJ/166/123 EXPRES radial volocity for τ Ceti (Korolik+, 2023)
Refining the Stellar Parameters of τ Ceti: a Pole-on Solar Analog
Korolik M., Roettenbacher R.M., Fischer D.A., Kane S.R., Perkins J.M.,
Monnier J.D., Davies C.L., Kraus S., Le Bouquin J.-B., Anugu N.,
Gardner T., Lanthermann C., Schaefer G.H., Setterholm B., Brewer J.M.,
Llama J., Zhao L.L., Szymkowiak A.E., Henry G.W.
<Astron. J., 166, 123 (2023)>
=2023AJ....166..123K 2023AJ....166..123K
ADC_Keywords: Stars, high-velocity; Stars, G-type; Spectra, optical;
Radial velocities
Keywords: Solar analogs ; Stellar properties ; Spectroscopy ; Long
baseline interferometry ; G dwarf stars
Abstract:
To accurately characterize the planets a star may be hosting, stellar
parameters must first be well determined. τCeti is a nearby solar
analog and often a target for exoplanet searches. Uncertainties in the
observed rotational velocities have made constraining τCeti's
inclination difficult. For planet candidates from radial velocity (RV)
observations, this leads to substantial uncertainties in the planetary
masses, as only the minimum mass (msini) can be constrained with RV.
In this paper, we used new long-baseline optical interferometric data
from the CHARA Array with the MIRC-X beam combiner and extreme
precision spectroscopic data from the Lowell Discovery Telescope with
EXPRES to improve constraints on the stellar parameters of τCeti.
Additional archival data were obtained from a Tennessee State
University Automatic Photometric Telescope and the Mount Wilson
Observatory HK project. These new and archival data sets led to
improved stellar parameter determinations, including a limb-darkened
angular diameter of 2.019±0.012mas and rotation period of
46±4days. By combining parameters from our data sets, we obtained
an estimate for the stellar inclination of 7°±7°. This
nearly pole-on orientation has implications for the previously
reported exoplanets. An analysis of the system dynamics suggests that
the planetary architecture described by Feng et al. may not retain
long-term stability for low orbital inclinations. Additionally, the
inclination of τCeti reveals a misalignment between the
inclinations of the stellar rotation axis and the previously measured
debris disk rotation axis (idisk=35°±10°).
Description:
The Extreme PREcision Spectrograph (EXPRES) at the 4.3m Lowell
Discovery Telescope (LDT) run by Lowell Observatory was used to obtain
200 spectra of τCeti over the period of time from 2019 August to
2021 October. The data from EXPRES reach a median resolving power of
R∼137500 and an radial velocity precision of 30cm/s for main-sequence
FGK stars with a target signal-to-noise ratio of ∼250.
Objects:
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RA (2000) DE Designation(s) (Period)
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01 44 04.08 -15 56 14.9 tau Ceti = * tau Cet (P=46d)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 24 200 EXPRES radial velocity data
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See also:
III/150 : Perkins Revised MK Types for the Cooler Stars (Keenan+ 1989)
III/159 : Ca II H and K Measurements Made at MWO (Duncan+ 1991)
J/ApJ/457/L99 : 25yr CaII-HK observations of FK nearby stars (Baliunas+, 1996)
J/A+A/348/897 : Ages of main-sequence stars (Lachaume+, 1999)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/ApJ/771/40 : Main-sequence A, F, G, & K stars photometry (Boyajian+, 2013)
J/A+A/582/A81 : Gaia FGK benchmark stars; abundances (Jofre+, 2015)
J/ApJ/803/90 : τ Cet chemical composition (Pagano+, 2015)
J/ApJS/225/32 : Extended abundance analysis of cool stars (Brewer+, 2016)
J/A+A/597/A137 : HD 123999 and Alpha Cen A and B OIFITS files (Kervella+, 2017)
J/A+A/623/A72 : Bin of Hipparcos stars from Gaia pm anomaly (Kervella+, 2019)
J/AJ/160/24 : Circumstellar dust of 104 stars with GPIES (Esposito+, 2020)
J/AJ/159/187 : 1st RVs with the EXPRES spectrograph 51Peg (Petersburg+, 2020)
J/AJ/163/183 : S-value for 59 Sun-like starswith HIRES and HKP (Baum+, 2022)
J/AJ/164/184 : ARMADA. II. Bin astrometry & radial velocity (Gardner+, 2022)
J/AJ/163/171 : The EXPRES Stellar Signals Project. II. RVel (Zhao+, 2022)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 11 F11.5 d MJD [58710/59505] Modified Julian date, JD-2400000.5
13- 18 F6.3 m/s RVel [-4.94/4.02] Radial velocity
20- 24 F5.3 m/s e_RVel [0.3/0.6] The 1-sigma uncertainty in RVel
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 22-Mar-2024