2018A&A...612A.111G


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.27CET11:42:19

2018A&A...612A.111G - Astronomy and Astrophysics, volume 612A, 111-111 (2018/4-1)

The atmospheric parameters of FGK stars using wavelet analysis of CORALIE spectra.

GILL S., MAXTED P.F.L. and SMALLEY B.

Abstract (from CDS):


Context. Atmospheric properties of F-, G- and K-type stars can be measured by spectral model fitting or with the analysis of equivalent width (EW) measurements. These methods require data with good signal-to-noise ratios (S/Ns) and reliable continuum normalisation. This is particularly challenging for the spectra we have obtained with the CORALIE echelle spectrograph for FGK stars with transiting M-dwarf companions. The spectra tend to have low S/Ns, which makes it difficult to analyse them using existing methods.
Aims. Our aim is to create a reliable automated spectral analysis routine to determine Teff, [Fe/H], Vsini from the CORALIE spectra of FGK stars.
Methods. We use wavelet decomposition to distinguish between noise, continuum trends, and stellar spectral features in the CORALIE spectra. A subset of wavelet coefficients from the target spectrum are compared to those from a grid of models in a Bayesian framework to determine the posterior probability distributions of the atmospheric parameters.
Results. By testing our method using synthetic spectra we found that our method converges on the best fitting atmospheric parameters. We test the wavelet method on 20 FGK exoplanet host stars for which higher-quality data have been independently analysed using EW measurements. We find that we can determine Teff to a precision of 85K, [Fe/H] to a precision of 0.06dex and Vsini to a precision of 1.35km/s for stars with Vsini≥5km/s. We find an offset in metallicity ~=-0.18dex relative to the EW fitting method. We can determine logg to a precision of 0.13dex but find systematic trends with Teff. Measurements of logg are only reliable enough to confirm dwarf-like surface gravity (logg~=4.5).
Conclusions. The wavelet method can be used to determine Teff, [Fe/H], and Vsini for FGK stars from CORALIE echelle spectra. Measurements of log g are unreliable but can confirm dwarf-like surface gravity. We find that our method is self consistent, and robust for spectra with S/N≳40.

Abstract Copyright: © ESO 2018

Journal keyword(s): stars: atmospheres

Simbad objects: 24

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Number of rows : 24

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 CD-24 102 * 00 20 38.5321093179 -23 56 08.793808265   11.388 10.779     ~ 24 1
2 HD 10069 * 01 37 25.0335097438 -45 40 40.376513381   9.74 9.30     F6IV/V 162 1
3 WASP-53 * 02 07 38.2093703588 -20 39 42.761678019   13.54 12.60 12.44 11.65 ~ 13 1
4 BD-07 436A PM* 02 28 37.2275829401 -07 03 38.378689023   11.07 10.29     G8 22 1
5 WASP-22 * 03 31 16.3269748036 -23 49 10.841600521   12.38 11.99 11.41   G 44 1
6 CD-57 1311 ** 05 55 32.6887769837 -57 17 26.066268562   10.456 9.934     ~ 13 0
7 WASP-23 PM* 06 44 30.6134894586 -42 45 42.666092659   13.42 12.52 12.31   ~ 31 1
8 WASP-19 LP* 09 53 40.0764883458 -45 39 33.055979403   13.05 12.31 12.12 11.35 G8V 140 1
9 WASP-31 * 11 17 45.3578468391 -19 03 17.216528280   12.01 11.66 11.98   F: 45 1
10 CD-31 10766 * 13 55 42.7119654298 -32 09 34.615276547   11.396 10.910     F7 53 1
11 WASP-16 * 14 18 43.9226513410 -20 16 31.842223819   12.51 11.29 11.00 10.49 G3V 51 1
12 NAME Proxima Centauri b Pl 14 29 42.9451234609 -62 40 46.170818907           ~ 237 0
13 WASP-24 * 15 08 51.7366806893 +02 20 35.964406086   12.00 11.22 11.43   F8-9 40 1
14 CD-27 10695 * 15 59 50.9489706053 -28 03 42.309432433   11.83 11.59 11.31 10.92 F4 96 1
15 WASP-80 PM* 20 12 40.1691752075 -02 08 39.191157456   12.810 11.939 11.510 10.279 K7V-M0V 40 1
16 HD 197286 PM* 20 44 10.2207500229 -39 13 30.859306335   9.98 9.50     F5V 64 1
17 BD-05 5432 PM* 21 00 06.1969250596 -05 05 40.037007561   10.93 9.87     ~ 29 1
18 TRAPPIST-1 LM* 23 06 29.3684052886 -05 02 29.031690445     18.798 16.466 14.024 M7.5e 561 0
19 WASP-6 * 23 12 37.7368657624 -22 40 26.277489164   12.90 11.91     G8V 72 1
20 WASP-4 PM* 23 34 15.0858223039 -42 03 41.049468209   13.51 12.48 11.9   G7V 134 1
21 CD-40 15273 PM* 23 51 31.0840161955 -39 54 24.259966546   12.15 11.33 10.896 10.10 K4V 36 1
22 WASP-30 * 23 53 38.0550935909 -10 07 05.096758883   12.15 11.91 11.51 10.83 F8V 25 0
23 WASP-5 V* 23 57 23.7565609528 -41 16 37.745589460   12.71 12.3 11.82 11.44 G4V 93 1
24 CD-35 16019 PM* 23 59 36.0711854449 -35 01 52.923483315   10.49 9.87 9.91   G6 82 0

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