2015A&A...582A..25A


Query : 2015A&A...582A..25A

2015A&A...582A..25A - Astronomy and Astrophysics, volume 582A, 25-25 (2015/10-1)

A seismic and gravitationally bound double star observed by Kepler. Implication for the presence of a convective core.

APPOURCHAUX T., ANTIA H.M., BALL W., CREEVEY O., LEBRETON Y., VERMA K., VORONTSOV S., CAMPANTE T.L., DAVIES G.R., GAULME P., REGULO C., HORCH E., HOWELL S., EVERETT M., CIARDI D., FOSSATI L., MIGLIO A., MONTALBAN J., CHAPLIN W.J., GARCIA R.A. and GIZON L.

Abstract (from CDS):

Solar-like oscillations have been observed by Kepler and CoRoT in many solar-type stars, thereby providing a way to probe stars using asteroseismology. The derivation of stellar parameters has usually been done with single stars. The aim of the paper is to derive the stellar parameters of a double-star system (HIP93511), for which an interferometric orbit has been observed along with asteroseismic measurements. We used a time series of nearly two years of data for the double star to detect the two oscillation-mode envelopes that appear in the power spectrum. Using a new scaling relation based on luminosity, we derived the radius and mass of each star. We derived the age of each star using two proxies: one based upon the large frequency separation and a new one based upon the small frequency separation. Using stellar modelling, the mode frequencies allowed us to derive the radius, the mass, and the age of each component. In addition, speckle interferometry performed since 2006 has enabled us to recover the orbit of the system and the total mass of the system. From the determination of the orbit, the total mass of the system is 2.34–0.33+0.45M. The total seismic mass using scaling relations is 2.47±0.07M. The seismic age derived using the new proxy based upon the small frequency separation is 3.5±0.3Gyr. Based on stellar modelling, the mean common age of the system is 2.7-3.9Gyr. The mean total seismic mass of the system is 2.34-2.53 M consistent with what we determined independently with the orbit. The stellar models provide the mean radius, mass, and age of the stars as RA=1.82-1.87R, MA=1.25-1.39M, AgeA=2.6-3.5Gyr; RB=1.22-1.25R, MB=1.08-1.14M, AgeB=3.35-4.21Gyr. The models provide two sets of values for Star A: [1.25-1.27]M and [1.34-1.39]M. We detect a convective core in Star A, while Star B does not have any. For the metallicity of the binary system of Z≃0.02, we set the limit between stars having a convective core in the range [1.14-1.25]M.

Abstract Copyright:

Journal keyword(s): asteroseismology - binaries: general - stars: evolution - stars: solar-type - astrometry

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 HD 49933 PM* 06 50 49.8309774552 -00 32 27.167495244   6.147 5.771 7.04   F3V 375 2
2 HD 52265 PM* 07 00 18.0357115416 -05 22 01.780929120   6.845 6.282     G0V 328 1
3 * alf Cen A SB* 14 39 36.49400 -60 50 02.3737 0.96 0.72 0.01     G2V 1270 1
4 BD+45 2796 PM* 18 56 21.2642726544 +45 30 53.234154468   9.80 9.29     G0.5IV 91 0
5 HD 176071 Er* 18 56 22.1268370056 +45 30 25.361404632   8.81 8.33     F8IV 83 0
6 HD 176465 ** 18 58 03.46393 +47 11 30.6471       8.462   G4V 55 0
7 HD 177153 PM* 19 01 39.6780721176 +41 29 24.328113936   7.76 7.21     G0 112 0
8 HD 177412 SB* 19 02 39.4175915928 +43 07 02.940702096   8.38 7.86     F6IV 64 0
9 HD 234856 Ro* 19 17 45.8018919144 +50 28 48.274775580   9.87 9.32     F9IV-V 79 0
10 * 16 Cyg A ** 19 41 48.9534996168 +50 31 30.219536784 6.79 6.59 5.95 5.50 5.17 G1.5Vb 755 0
11 * 16 Cyg B PM* 19 41 51.9726777456 +50 31 03.089030916 7.07 6.86 6.20 5.76 5.42 G3V 882 1
12 * gam Pav PM* 21 26 26.6049826473 -65 21 58.313057521 4.57 4.70 4.22 3.75 3.45 F9VFe-1.4CH-0.7 411 0

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