J/A+A/575/A18 Revising the ages of planet-hosting stars (Bonfanti+, 2015)
Revising the ages of planet-hosting stars.
Bonfanti A., Ortolani S., Piotto G., Nascimbeni V.
<Astron. Astrophys. 575, A18 (2015)>
=2015A&A...575A..18B 2015A&A...575A..18B
ADC_Keywords: Stars, fundamental ; Models, evolutionary ; Isochrones ;
Effective temperatures ; Stars, ages ; Stars, masses
Keywords: stars: fundamental parameters
Abstract:
This article aims to measure the age of stars with planets (SWP)
through stellar tracks and isochrones computed with the Padova &
Trieste Stellar Evolutionary Code (PARSEC).
We developed algorithms based on two different techniques for
determining the ages of field stars: isochrone placement and Bayesian
estimation. Their application to a synthetic sample of coeval stars
shows the intrinsic limits of each method. For instance, the Bayesian
computation of the modal age tends to select the extreme age values in
the isochrones grid. Therefore, we used the isochrone placement
technique to measure the ages of 317 SWP.
We found that ∼6% of SWP have ages lower than 0.5Gyr. The age
distribution peaks in the interval [1.5, 2]Gyr, then it decreases.
However, ∼7% of the stars are older than 11Gyr. The Sun turns out to
be a common star that hosts planets, when considering its evolutionary
stage. Our SWP age distribution is less peaked and slightly shifted
towards lower ages if compared with ages in the literature and based
on the isochrone fit. In particular, there are no ages below 0.5Gyr
in the literature.
Description:
Age, effective temperature, luminosity, surface gravity, mass and
radius of 317 planet-hosting stars computed according to Padova
evolutionary models (tracks and isochrones).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 99 317 SWP parameters determined through Padova isochrones
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Star Name
13- 19 F7.4 Gyr Age [0.003/12.6] Stellar age
21- 26 F6.4 Gyr e_Age [0.0005/4.7] rms uncertainty on age
28- 32 I5 K Teff [3704/10942] Effective temperature
34- 36 I3 K e_Teff [2/110] rms uncertainty on Teff
38- 45 F8.4 Lsun L [0.1/504] Star Luminosity
47- 53 F7.4 Lsun e_L [0/21] rms uncertainty on L
55- 61 F7.4 Msun M [0.4/2.6] Star Mass
63- 68 F6.4 Msun e_M [0.0002/0.2] rms uncertainty on M
70- 75 F6.4 [cm/s2] logg [1.1/4.8] Logarithm of surface gravity
77- 82 F6.4 [cm/s2] e_logg [0.0001/0.1] rms uncertainty on logg
84- 90 F7.4 Rsun Rad [0.5/49] Radius
92- 97 F6.4 Rsun e_Rad [0.0001/1.8] rms uncertainty on Rad
99 I1 --- fPlx [0,1]? flag on parallax (0=Hipparcos) (1)
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Note (1): 73 stars have not parallax taken from Hipparcos. Flag as follows:
0 = Measured parallax (taken from Hipparcos)
1 = Inferred parallax (usually from spectroscopy); not necessarily reliable
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Acknowledgements:
Andrea Bonfanti, andrea.bonfanti.1(at)studenti.unipd.it
(End) Andrea Bonfanti [UniPD, Italy], Patricia Vannier [CDS] 12-Feb-2015