J/MNRAS/506/306 EBLM project. VIII.43 M-dwarf light curve (Swayne+, 2021)
The EBLM project. VIII. First results for M-dwarf mass, radius and effective
temperature measurements using CHEOPS light curves.
Swayne M.I., Maxted P.F.L., Triaud A.H.M.J., Sousa S.G., Broeg C.,
Floren H.-G., Guterman P., Simon A.E., Boisse I., Bonfanti A., Martin D.,
Santerne A., Salmon S., Standing M.R., Van Grootel V., Wilson T.G.,
Alibert Y., Alonso R., Anglada Escude G., Asquier J., Barczy T., Barrado D.,
Barros S.C.C., Battley M., Baumjohann W., Beck M., Beck T., Bekkelien A.,
Benz W., Billot N., Bonfils X., Brandeker A., Busch M.-D., Cabrera J.,
Charnoz S., Collier Cameron A., Csizmadia Sz., Davies M.B., Deleuil M.,
Deline A., Delrez L., Demangeon O.D.S., Demory B.-O., Dransfield G.,
Ehrenreich D., Erikson A., Fortier A., Fossati L., Fridlund M., Futyan D.,
Gandolfi D., Gillon M., Guedel M., Hebrard G., Heidari N., Hellier C.,
Heng K., Hobson M., Hoyer S., Isaak K.G., Kiss L., Kunovac Hodzic V.,
Lalitha S., Laskar J., Lecavelier des Etangs A., Lendl M., Lovis C.,
Magrin D., Marafatto L., McCormac J., Miller N., Nascimbeni V., Olofsson G.,
Ottensamer R., Pagano I., Palle E., Peter G., Piotto G., Pollacco D.,
Queloz D., Ragazzoni R., Rando N., Rauer H., Ribas I., Santos N.C.,
Scandariato G., Segransan D., Smith A.M.S., Steinberger M., Steller M.,
Szabo G.M., Thomas N., Udry S., Walter I., Walton N.A., Willett E.
<Mon. Not. R. Astron. Soc. 506, 306-322 (2021)>
=2021MNRAS.506..306S 2021MNRAS.506..306S (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Stars, M-type ; Photometry
Keywords: binaries: eclipsing - stars: fundamental parameters -
stars: low-mass - techniques: photometric - techniques: spectroscopic
Abstract:
The accuracy of theoretical mass, radius and effective temperature
values for M-dwarf stars is an active topic of debate. Differences
between observed and theoretical values have raised the possibility
that current theoretical stellar structure and evolution models are
inaccurate towards the low-mass end of the main sequence. To explore
this issue we use the CHEOPS satellite to obtain high-precision light
curves of eclipsing binaries with low mass stellar companions. We use
these light curves combined with the spectroscopic orbit for the
solar-type companion to measure the mass, radius and effective
temperature of the M-dwarf star. Here we present the analysis of three
eclipsing binaries. We use the pycheops data analysis software to fit
the observed transit and eclipse events of each system. Two of our
systems were also observed by the TESS satellite - we similarly
analyse these light curves for comparison. We find consistent results
between CHEOPS and TESS, presenting three stellar radii and two
stellar effective temperature values of low-mass stellar objects.
These initial results from our on-going observing programme with
CHEOPS show that we can expect to have ∼24 new mass, radius and
effective temperature measurements for very low mass stars within the
next few years.
Description:
Two visits each of three EBLMs were obtained with CHEOPS to observe
the primary transit and secondary eclipse events for each object. Each
visit used exposure times of 60s and was obtained as part of a CHEOPS
GTO programme.
Objects:
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RA (2000) DE Designation(s)
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17 41 21.28 +31 24 55.2 EBLM J1741+31 = TYC 2606-1838-1
19 34 25.69 -42 23 12.0 EBLM J1934-42 = UCAC2 13875304
20 46 43.88 +06 18 09.7 EBLM J2046+06 = TYC 524-2528-1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
j1741.dat 59 533 Detrended CHEOPS light curve containing the
transit and eclipse of EBLM J1741+31
j1934.dat 59 519 Detrended CHEOPS light curve containing the
transit and eclipse of EBLM J1934-42
j2046.dat 60 827 Detrended CHEOPS light curve containing the
transit and eclipse of EBLM J2046+06
list.dat 129 6 List of fits files
fits/* . 6 Individual fits files
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Byte-by-byte Description of file: j1741.dat j1934.dat j2046.dat
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Bytes Format Units Label Explanations
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1- 18 F18.13 d Time Time of observation (JD-2450000)
20- 37 F18.16 --- Flux Detrended flux
39- 60 F22.20 --- e_Flux Error on flux
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right Ascension of center (J2000)
4- 5 I2 min RAm Right Ascension of center (J2000)
7- 11 F5.2 s RAs Right Ascension of center (J2000)
12 A1 --- DE- Declination sign of center (J2000)
13- 14 I2 deg DEd Declination of center (J2000)
16- 17 I2 arcmin DEm Declination of center (J2000)
19- 22 F4.1 arcsec DEs Declination of center (J2000)
24- 26 I3 --- Nx Number of observations
28- 46 A19 "datime" Obs.Date Observation Date
48- 49 I2 Kibyte size Size of FITS file
51- 89 A39 --- FileName Name of FITS file, in subdirectory fits
91-129 A39 --- Title Title of the FITS file
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Acknowledgements:
Matthew Iain Swayne, m.i.swayne(at)keele.ac.uk
(End) Patricia Vannier [CDS] 13-Jul-2021