Press Release
Free Access
Issue
A&A
Volume 576, April 2015
Article Number L12
Number of page(s) 7
Section Letters
DOI https://doi.org/10.1051/0004-6361/201525865
Published online 10 April 2015

Online material

Appendix A: Best-candidate young α-enhanced stars in the CoRoGEE sample

Table A.1 summarises our measured quantities for the best-candidate young α-enhanced stars (17 2σ-outliers; blue large pentagons in Fig. 1, and 11 1σ-outliers; blue stars in Fig. 1). We first report our input values: the adopted seismic parameters Δν and νmax (as computed by automatic as well as supervised analyses of the CoRoT light curves), ASPCAP spectroscopic parameters Teff, [Fe/H], [α/Fe], and the number of APOGEE observations, NAPO. We note that all stars in question have been observed at very high signal-to-noise ratios (S/N> 140 per resolution element). The radial-velocity scatter between subsequent observations is always smaller than 0.6 km s-1; meaning that their values are consistent with all stars being single stars or widely separated binaries.

We also present the estimated stellar masses Mscale, as determined from seismic scaling relations and the 1σ upper-limits for the ages (as determined by PARAM). A comparison of the masses estimated by PARAM and those inferred directly from the scaling relations is reported in A15 for the full CoRoGEE sample. Also listed are the current Galactocentric positions RGal and ZGal and the guiding radius Rg of each star.

We also show a note on the quality of the light curves (Q) and a flag based on the supervised analysis. Because the automated and supervised analyses sometimes yield different results,

we recomputed masses and ages using the individually obtained Δν and νmax values and updated uncertainties where necessary. As expected, the numbers of the young α-enhanced stars are slightly different. In Table A.1, we only report the robust 2σ- and 1σ-outliers.

The individual supervised analysis shows that:

  • 1.

    After the individual analysis, still 28 stars out of39 candidates fulfilled our outlier criterion;

  • 2.

    Four stars that seemed to be 2σ-outliers were shifted to older ages: CoRoT 101093867, 101071033, 102645343, and 10264381. Similarly, seven candidate 1σ-outliers fall out of the sample: CoRoT 101057962, 101041814, 102626343, 100886873, 101208801, 101212022, and 101227666.

  • 3.

    One star (CoRoT 101071033) had to be excluded from the parent sample due to the very poor quality of its light curve;

  • 4.

    CoRoT 101093867 is a complex case, where both Δν values appear as possible solutions; for six other stars, another solution is possible, because the light curve S/N is not high enough to undoubtedly resolve the radial/dipole mode possible mismatch (such cases cannot be seen in the general blind automated analysis);

  • 5.

    For CoRoT 100958571, the solution obtained through supervised fitting, close to the one found by the automated pipeline, should be preferred. Also, for most of the remaining stars, slight improvements in the determination of the seismic parameters are possible.

Table A.1

Best-candidate young α-enhanced stars: seismic and spectroscopic adopted parameters and uncertainties, stellar masses and ages, current Galactocentric positions RGal and ZGal, and guiding-centre radii Rg.


© ESO, 2015

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