J/AJ/168/252 SPIRou & HARPS obs. template star parameters (Artigau+, 2024)
Measuring sub-Kelvin variations in stellar temperature with high-resolution
spectroscopy.
Artigau E., Cadieux C., Cook N.J., Doyon R., Dauplaise L., Arnold L.,
Cadieux M., Donati J.-F., Cristofari P., Delfosse X., Fouque P.,
Moutou C., Larue P., Allart R.
<Astron. J., 168, 252 (2024)>
=2024AJ....168..252A 2024AJ....168..252A
ADC_Keywords: Spectroscopy ; Optical ; Infrared ; Effective temperatures ;
Abundances, [Fe/H]
Keywords: Stellar effective temperatures ; High resolution spectroscopy ;
Time series analysis
Abstract:
The detection of stellar variability often relies on the measurement
of selected activity indicators, such as coronal emission lines and
nonthermal emissions. On the flip side, the effective stellar
temperature is normally seen as one of the key fundamental parameters
(with mass and radius) to understanding the basic physical nature of a
star and its relation with its environment (e.g., planetary
instellation). We present a novel approach for measuring disk-averaged
temperature variations to sub-Kelvin accuracy inspired by algorithms
developed for precision radial velocity (pRV). This framework uses the
entire content of the spectrum, not just preidentified lines, and can
be applied to existing data obtained with high-resolution
spectrographs. We demonstrate the framework by recovering the known
rotation periods and temperature modulation of Barnard star and AU Mic
in data sets obtained in the infrared with SPIRou at CHFT and at
optical wavelengths on ε Eridani with HARPS at ESO 3.6m
telescope. We use observations of the transiting hot Jupiter
HD189733b, obtained with SPIRou, to show that this method can unveil
the minute temperature variation signature expected during the transit
event, an effect analogous to the Rossiter-McLaughlin effect but in
temperature space. This method is a powerful new tool for
characterizing stellar activity, and in particular temperature and
magnetic features at the surfaces of cool stars, affecting both pRV
and transit spectroscopic observations. We demonstrate this method in
the context of high-resolution spectroscopy but it could be used at
lower resolution.
Description:
We focus on data sets obtained with two instruments, the
SPectropolarimetre InfraROUge (SPIRou), at the 3.6m optical/infrared
Canada-France-Hawaii Telescope (CFHT) in Maunakea, Hawaii and the High
Accuracy Radial velocity Planet Searcher (HARPS), at ESO 3.6m optical
telescope in La Silla Observatory, Chile, to showcase the performance
of this activity indicator at both optical and infrared wavelengths.
The M dwarf templates from SPIRou that were used are observations from
the SPIRou legacy survey (Fouque+, 2023A&A...672A..52F 2023A&A...672A..52F;
Moutou+ 2023, J/A+A/678/A207), while K and G stars templates are archival
observations obtained in the context of exoplanet transit surveys.
HARPS data was obtained from the ESO archive (http://archive.eso.org/).
Each template is constructed from the median combination of all
observations of each target. Effective temperature, metallicity, and
surface gravity were taken from Gaia DR3 (Gaia collab. 2022, I/355).
For more information on template construction and sample selection
criteria, see Section 3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 54 141 *Parameters for all stars used as templates
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Note on tablea1.dat: The template derivatives used here are provided for the
HARPS and SPIRou domains in the LBL webpage (http://lbl.exoplanets.ca/).
Table A1 provides the list of objects used as HARPS and/or SPIRou
templates, the Teff used for the polynomial fit in Section 3, the
surface gravity, and the systemic velocity for template alignment.
See the Appendix.
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See also:
B/cfht : Log of CFHT Exposures (CADC, 1979-)
B/eso : ESO Science Archive Catalog (ESO, 1991-2025)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/A+A/506/303 : CoRoT-7 radial velocities (Queloz+, 2009)
J/ApJ/744/138 : Calibrated visibilities of ε Eri (Baines+, 2012)
J/A+A/544/A106 : p-mode frequencies of the solar twin 18 Sco (Bazot+, 2012)
J/A+A/541/A9 : M dwarfs activity and radial velocity (Gomes da Silva+, 2012)
J/other/Nat/563.365 : Barnard's star radial velocity curve (Ribas+, 2018)
J/A+A/623/A44 : CARMENES M-dwarfs activity indicators (Schoefer+, 2019)
J/A+A/649/A6 : Gaia Cat. of Nearby Stars - GCNS (Gaia collaboration, 2021)
J/AJ/162/181 : RV & Hipparcos positions: epsilon Eridani (Llop-sayson+, 2021)
J/AJ/162/61 : RV follow up of Barnard's star with HPF (Lubin+, 2021)
J/A+A/654/A159 : CHEOPS photometry of Au Mic b transits in 2020 (Szabo+, 2021)
J/A+A/666/A196 : Proxima telluric-corrected ESPRESSO RV (Allart+, 2022)
J/A+A/664/A34 : Sun and HD128621 spectra (Al Moulla+, 2022)
J/AJ/164/96 : SPIRou and IRD radial velocity of TOI-1452 (Cadieux+, 2022)
J/AJ/163/19 : EXPRES. III. Phot. & RV of eps Eridani (Roettenbacher+, 2022)
J/A+A/659/L7 : AU Mic b and c transits with CHEOPS (Szabo+, 2022)
J/A+A/674/A110 : Gl 388 (AD Leo) RV curves (Carmona+, 2023)
J/A+A/678/A207 : SPIRou GJ 876 and GJ 1148 RV curves (Moutou+, 2023)
http://archive.eso.org/ : ESO Science Archive
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- ID Simbad identifier
18- 30 A13 --- Inst Instrument identifier(s) (1)
32- 35 I4 K Teff [2863/6319] Effective temperature from Gaia DR3
(I/355)
37- 41 F5.2 [Sun] [Fe/H] [-0.5/0.5] Metallicity from Gaia DR3 (I/355)
43- 46 F4.2 [cm/s2] logg [4/5.2] log surface gravity from Gaia DR3
(I/355)
48- 54 I7 m/s Vsys [-9.8e4/1.5e5] Systemic velocity
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Note (1): Instruments as follows:
HARPS = High Accuracy Radial velocity Planet Searcher,
at ESO 3.6m optical telescope, La Silla Observatory, Chile
(97 occurrences)
SPIRou = SPectropolarimetre InfraROUge,
at the 3.6m optical/infrared Canada-France-Hawaii Telescope,
Maunakea, Hawaii (36 occurrences)
HARPS, SPIRou = (8 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 01-Jul-2025