2011A&A...533A..27P


Query : 2011A&A...533A..27P

2011A&A...533A..27P - Astronomy and Astrophysics, volume 533A, 27-27 (2011/9-1)

Determination of the stellar parameters of C-rich hydrostatic stars from spectro-interferometric observations.

PALADINI C., VAN BELLE G.T., ARINGER B., HRON J., REEGEN P., DAVIS C.J. and LEBZELTER T.

Abstract (from CDS):

Giant stars, and especially C-rich giants, contribute significantly to the chemical enrichment of galaxies. The determination of precise parameters for these stars is a necessary prerequisite for a proper implementation of this evolutionary phase in the models of galaxies. Infrared interferometry opened new horizons in the study of the stellar parameters of giant stars, and provided new important constraints for the atmospheric and evolutionary models. We aim to determine which stellar parameters can be constrained by using infrared interferometry and spectroscopy; for C-stars in particular we aim to determine the precision that can be achieved as well as its limitations. For this purpose we obtained new infrared spectra and combined them with unpublished interferometric measurements for five mildly variable carbon-rich asymptotic giant branch stars. The observations were compared with a large grid of hydrostatic model atmospheres and with new isochrones that include the predictions of the thermally pulsing phase. For the very first time we are able to reproduce spectra in the range between 0.9 and 4 µm, and K broad band interferometry with hydrostatic model atmospheres. Temperature, mass, log(g), C/O and a reasonable range for the distance were derived for all objects of our study. All our targets have at least one combination of best-fitting parameters that lies in the region of the HR-diagram where C-stars are predicted. We confirm that low-resolution spectroscopy is not sensitive to the mass and log(g) determination. For hydrostatic objects the 3µm feature is very sensitive to temperature variations, therefore it is a very powerful tool for accurate temperature determinations. Interferometry can constrain mass, radius, and log(g), but a distance has to be assumed. The large uncertainty in the distance measurements available for C-rich stars remains a major problem.

Abstract Copyright:

Journal keyword(s): stars: AGB and post-AGB - stars: atmospheres - stars: carbon - stars: fundamental parameters - techniques: spectroscopic - techniques: high angular resolution

Simbad objects: 8

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Number of rows : 8
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 * g Psc ** 01 11 06.7652458697 +31 25 29.016084267   5.400 5.152     F0V 49 0
2 V* Z Psc C* 01 16 05.0295407752 +25 46 09.695709530 12.85 9.46 6.84     C-N5 167 0
3 V* CR Gem C* 06 34 23.9159138911 +16 04 30.321998626   12.37 8.67     C-N5 69 0
4 HD 50277 * 06 52 49.4710094560 +08 22 49.434264933   5.996 5.742     F0Vn 60 0
5 V* RV Mon C* 06 58 21.4890395542 +06 10 01.560306362   10.4 7.47     C4,5 95 1
6 V* HK Lyr C* 18 42 50.0050823492 +36 57 30.883170555 10.730 10.730 7.650     C-N5 97 0
7 V* DR Ser C* 18 47 21.0229663571 +05 27 18.603538975   13.39 10.40     C5,4 69 0
8 * tet01 Ser PM* 18 56 13.1878925839 +04 12 12.977820598   4.74 4.57     A5V 120 0

    Equat.    Gal    SGal    Ecl

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2021.07.25-18:59:33

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