2012A&A...545A..17C


Query : 2012A&A...545A..17C

2012A&A...545A..17C - Astronomy and Astrophysics, volume 545A, 17-17 (2012/9-1)

Fundamental properties of the population II fiducial stars HD 122563 and Gmb 1830 from CHARA interferometric observations.

CREEVEY O.L., THEVENIN F., BOYAJIAN T.S., KERVELLA P., CHIAVASSA A., BIGOT L., MERAND A., HEITER U., MOREL P., PICHON B., McALISTER H.A., TEN BRUMMELAAR T.A., COLLET R., VAN BELLE G.T., COUDE DU FORESTO V., FARRINGTON C., GOLDFINGER P.J., STURMANN J., STURMANN L. and TURNER N.

Abstract (from CDS):

We have determined the angular diameters of two metal-poor stars, HD122563 and Gmb1830, using CHARA and Palomar Testbed Interferometer observations. For the giant star HD122563, we derive an angular diameter θ3D=0.940±0.011-milliarcseconds (mas) using limb-darkening from 3D convection simulations and for the dwarf star Gmb1830 (HD103095) we obtain a 1D limb-darkened angular diameter θ1D=0.679±0.007mas. Coupling the angular diameters with photometry yields effective temperatures with precisions better than 55K (Teff=4598±41K and 4818±54K - for the giant and the dwarf star, respectively). Including their distances results in very well-determined luminosities and radii (L=230±7L, R=24.1±1.1R and L=0.213±0.002L, R=0.665±0.014R, respectively). We used the CESAM2k stellar structure and evolution code in order to produce models that fit the observational data. We found values of the mixing-length parameter α (which describes 1D convection) that depend on the mass of the star. The masses were determined from the models with precisions of <3% and with the well-measured radii excellent constraints on the surface gravity are obtained (logg=1.60±0.04, 4.59±0.02dex, respectively). The very small errors on both logg and Teff provide stringent constraints for spectroscopic analyses given the sensitivity of abundances to both of these values. The precise determination of Teff for the two stars brings into question the photometric scales for metal-poor stars.

Abstract Copyright:

Journal keyword(s): stars: fundamental parameters - stars: individual: HD122563 - stars: low-mass - stars: Population II - Galaxy: halo - stars: individual: HD103095

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 * mu. Cas SB* 01 08 16.3029454473 +54 55 12.561201263 5.93 5.86 5.17 4.55 4.13 G5Vb 559 1
2 HD 103095 Pe* 11 52 58.7673387755 +37 43 07.254113125 7.38 7.20 6.45 5.80 5.35 K1V_Fe-1.5 776 1
3 HD 103799 PM* 11 57 14.5832839344 +40 20 37.463173692       6.3   F6V 71 0
4 HD 106184 * 12 13 03.0855017592 +28 38 05.763267492   9.26 7.68     K5III 21 0
5 HD 108123 PM* 12 25 15.1084294176 +23 55 34.325009796   7.12 6.02     K1III 51 0
6 HD 119550 PM* 13 43 35.6994238125 +14 21 56.183577981   7.57   6.5   G2V 68 0
7 HD 120066 PM* 13 46 57.1225636378 +06 21 01.346102072   6.96   5.9   G0V 142 0
8 HD 120934 * 13 52 18.4064027184 +12 09 54.497118312   6.138 6.098     A1V 34 0
9 HD 121560 PM* 13 55 49.9935853152 +14 03 23.407899444   6.66   5.9   F6V 132 0
10 HD 122365 * 14 01 20.4264941184 +08 53 41.617038696   6.058 5.973     A2V 33 0
11 HD 122563 Pe* 14 02 31.8455084952 +09 41 09.944391876 7.47 7.10 6.19 5.37 4.79 G8:III:Fe-5 811 0
12 HD 127227 * 14 29 53.6890570656 +16 12 31.532473368   9.04 7.53     K5III 31 0
13 * 32 Boo PM* 14 41 43.5203419224 +11 39 38.383245108   6.50   5.0   G8III 104 0

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2023.02.03-18:24:01

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