J/A+A/585/A5 Exoplanet hosts/field stars age consistency (Bonfanti+, 2016)
Age consistency between exoplanet hosts and field stars.
Bonfanti A., Ortolani S., Nascimbeni V.
<Astron. Astrophys. 585, A5 (2016)>
=2016A&A...585A...5B 2016A&A...585A...5B (SIMBAD/NED BibCode)
ADC_Keywords: Models, evolutionary ; Fundamental catalog ; Isochrones ;
Stars, fundamental ; Effective temperatures ; Stars, ages ;
Stars, masses
Keywords: stars: evolution - Hertzsprung-Russell and C-M diagrams -
planetary systems
Abstract:
Transiting planets around stars are discovered mostly through
photometric surveys. Unlike radial velocity surveys, photometric
surveys do not tend to target slow rotators, inactive or metal-rich
stars. Nevertheless, we suspect that observational biases could also
impact transiting-planet hosts.
This paper aims to evaluate how selection effects reflect on the
evolutionary stage of both a limited sample of transiting-planet host
stars (TPH) and a wider sample of planet-hosting stars detected
through radial velocity analysis. Then, thanks to uniform derivation
of stellar ages, a homogeneous comparison between exoplanet hosts and
field star age distributions is developed.
Stellar parameters have been computed through our custom-developed
isochrone placement algorithm, according to Padova evolutionary
models. The notable aspects of our algorithm include the treatment of
element diffusion, activity checks in terms of logR'HK and vsini,
and the evaluation of the stellar evolutionary speed in the
Hertzsprung-Russel diagram in order to better constrain age. Working
with TPH, the observational stellar mean density ρ* allows us to
compute stellar luminosity even if the distance is not available, by
combining ρ_* with the spectroscopic logg.
The median value of the TPH ages is ∼5Gyr. Even if this sample is not
very large, however the result is very similar to what we found for
the sample of spectroscopic hosts, whose modal and median values are
[3, 3.5)Gyr and ∼4.8Gyr, respectively. Thus, these stellar samples
suffer almost the same selection effects. An analysis of MS stars of
the solar neighbourhood belonging to the same spectral types bring to
an age distribution similar to the previous ones and centered around
solar age value. Therefore, the age of our Sun is consistent with the
age distribution of solar neighbourhood stars with spectral types from
late F to early K, regardless of whether they harbour planets or not.
We considered the possibility that our selected samples are older than
the average disc population.
Description:
Age, effective temperature, luminosity, surface gravity, mass and
radius of 335 planet-hosting stars computed according to PARSEC
evolutionary models (tracks and isochrones).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 93 335 Isochronal parameters of planet-hosting stars
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Star name
13- 17 F5.2 Gyr Age Stellar age
19- 22 F4.2 Gyr e_Age Uncertainty on age
24- 27 I4 K Teff Effective temperature
29- 31 I3 K e_Teff Uncertainty on Teff
33- 40 F8.4 Lsun L Luminosity
42- 48 F7.4 Lsun e_L Uncertainty on L
50- 55 F6.4 Msun M Mass
57- 62 F6.4 Msun e_M Uncertainty on M
64- 69 F6.4 [cm/s2] logg Logarithm of surface gravity
71- 76 F6.4 [cm/s2] e_logg Uncertainty on logg
78- 83 F6.3 Rsun Rad Radius
85- 89 F5.3 Rsun e_Rad Uncertainty on Rad
91 I1 --- Bin [0,1]? Flag on stellar multiplicity (1)
93 I1 --- Tr [0,1]? Flag on planet detection through
transit method (2)
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Note (1): Flag on stellar multiplicity as follows:
0 = star reported as single
1 = star reported as in a binary or multiple system
Note (2): Flag on planet detection through transit method as follows:
0 = no planets around the star have been detected through transit method
1 = the star hosts at least one planet detected through transit method
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Acknowledgements:
Andrea Bonfanti, andrea.bonfanti.1(at)studenti.unipd.it
(End) Andrea Bonfanti [UniPD, Italy], Patricia Vannier [CDS] 22-Jan-2016