J/A+A/674/A110 Gl 388 (AD Leo) RV curves (Carmona+, 2023)
Near-IR and optical radial velocities of the active M dwarf star Gl 388 (AD Leo)
with SPIRou at CFHT and SOPHIE at OHP.
A 2.23 day rotation period and no evidence for a corotating planet.
Carmona A., Delfosse X., Bellotti S., Cortes-Zuleta P., Ould-Elhkim M.,
Heidari N., Mignon L., Donati J.F., Moutou C., Cook N., Artigau E.,
Fouque P., Martioli E., Cadieux C., Morin J., Forveille T., Boisse I.,
Hebrard G., Diaz R.F., Lafreniere D., Kiefer F., Petit P., Doyon R.,
Acuna L., Arnold L., Bonfils X., Bouchy F., Bourrier V., Dalal S.,
Deleuil M., Demangeon O., Dumusque X., Hara N., Hoyer S., Mousis O.,
Santerne A., Segrasan D., Stalport M., Udry S.
<Astron. Astrophys., 674, A110 (2023)>
=2023A&A...674A.110C 2023A&A...674A.110C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Stars, M-type ; Radial velocities ;
Optical ; Infrared
Keywords: planetary systems - stars: low-mass - methods: observational -
techniques: spectroscopic - techniques: radial velocities
Abstract:
The search for extrasolar planets around the nearest M dwarfs is a
crucial step toward identifying the nearest Earth-like planets. One of
the main challenges in this search is that M dwarfs can be
magnetically active and stellar activity can produce radial velocity
(RV) signals that could mimic those of a planet.
We aim to investigate whether the 2.2-day period observed in optical
RVs of the nearby active M dwarf star Gl 388 (AD Leo) is due to
stellar activity or to a planet that corotates with the star as
suggested in the past.
We obtained quasi-simultaneous RVs of Gl 388 from 2019 to 2021 with
SOPHIE, the optical echelle spectrograph R∼75k) at the Observatoire
de Haute-Provence in France, and RV and Stokes V measurements with
SPIRou, the near-infrared spectropolarimeter at the Canada France
Hawaii Telescope (R∼70k).
The SOPHIE RV time series (precision of 3-5m/s per visit) displays a
periodic signal with a 2.23±0.01 day period and 23.6±0.5m/s
amplitude, which is consistent with previous HARPS observations
obtained in 2005-2006. The SPIRou RV time series (precision of 2m/s
per visit) is flat at 5m/s rms and displays no periodic signals. RV
signals of amplitude higher than 5.3m/s at a period of 2.23 days can
be excluded with a confidence level higher than 99%. Using the
modulation of the longitudinal magnetic field (Bl) measured with
SPIRou as a proxy of stellar rotation, we measure a rotation period of
2.2305±0.0016 days.
SPIRou RV measurements provide solid evidence that the periodic
variability of the optical RVs of Gl 388 is due to stellar activity
rather than to a corotating planet. The magnetic activity nature of
the optical RV signal is further confirmed by the modulation of Bl
with the same period. The SPIRou campaign on Gl 388 demonstrates the
power of near-infrared RV to confirm or infirm planet candidates
discovered in the optical around active stars. Our SPIRou observations
additionally reiterate how effective spectropolarimetry is at
determining the stellar rotation period from the variations of Bl.
Description:
Contemporaneous new RV and spectropolarimetry observations of the
magnetically active M dwarf Gl 388 obtained between 2019 and 2021,
with the optical high-resolution spectrometer SOPHIE at OHP and the
near-IR high-resolution spectropolarimeter SPIRou at CHFT. Our
observations were obtained ten to 15yr after previous RV measurements
with HARPS at la Silla (2005 and 2006) and optical spectropolarimetry
observations with ESPaDOnS at CFHT (2007 and 2008).
Objects:
-------------------------------------------------
RA (2000) DE Designation(s)
-------------------------------------------------
10 19 36.28 +19 52 12.0 Gl 388 = V* AD Leo
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablec1.dat 32 51 HARPS RV measurements of Gl 388
tablec2.dat 47 71 SOPHIE RV measurements of Gl 388
tablec3.dat 72 74 SPIRou RV and Bl measurements of Gl 388
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See also:
J/A+A/637/A13 : AD Leo high resolution spectra (Muheki+, 2020)
J/A+A/638/A5 : HD 285507 and AD Leo light and velocity curves (Carleo+, 2020)
J/A+A/666/A143 : AD Leo RV and stellar activity indices (Kossakowski+, 2022)
J/A+A/669/A118 : AD Leo spectral observations (Wollmann+, 2023)
J/A+A/676/A56 : Large-scale magnetic field of AD Leo (Bellotti+, 2023)
Byte-by-byte Description of file: tablec1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 "date" Obs.date Observation date
12- 22 F11.5 d BJD Barycentric Julian date (BJD-2400000)
24- 28 F5.1 m/s dRV Relative radial velocity
30- 32 F3.1 m/s e_dRV Relative radial velocity error
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Byte-by-byte Description of file: tablec2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 "date" Obs.date Observation date
12- 22 F11.5 d BJD Barycentric Julian date (BJD-2400000)
24- 30 F7.4 km/s RV Radial velocity
32- 37 F6.4 km/s e_RV Radial velocity error
39- 43 F5.1 m/s dRV Relative radial velocity
45- 47 F3.1 m/s e_dRV Relative radial velocity error
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Byte-by-byte Description of file: tablec3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 "date" Obs.date Observation date
12- 22 F11.5 d BJD Barycentric Julian date (BJD-2400000)
24- 30 F7.4 km/s RV Radial velocity
32- 37 F6.4 km/s e_RV Radial velocity error
39- 43 F5.1 m/s dRV Relative radial velocity
45- 47 F3.1 m/s e_dRV Relative radial velocity error
49- 55 F7.2 gauss Bl ?=- Longitudinal magnetic field
57- 60 F4.1 gauss e_Bl ?=- Longitudinal magnetic field error
62- 67 F6.1 gauss Bl2 ? Second longitudinal magnetic field value
69- 72 F4.1 gauss e_Bl2 ? Second longitudinal magnetic field error
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 14-Aug-2023