2010A&A...516A..42C


Query : 2010A&A...516A..42C

2010A&A...516A..42C - Astronomy and Astrophysics, volume 516, A42-42 (2010/6-2)

Absolute dimensions of eclipsing binaries. XXVIII. BK Pegasi and other F-type binaries: prospects for calibration of convective core overshoot.

CLAUSEN J.V., FRANDSEN S., BRUNTT H., OLSEN E.H., HELT B.E., GREGERSEN K., JUNCHER D. and KROGSTRUP P.

Abstract (from CDS):

Double-lined, detached eclipsing binaries are our main source for accurate stellar masses and radii. In this paper we focus on the 1.15-1.70M interval where convective core overshoot is gradually ramped up in theoretical evolutionary models. We aim to determine absolute dimensions and abundances for the F-type detached eclipsing binary BKPeg, and to perform a detailed comparison with results from recent stellar evolutionary models, including a sample of previously studied systems with accurate parameters. uvby light curves and uvbyβ standard photometry were obtained with the Stroemgren Automatic Telescope, ESO, La Silla, and high-resolution spectra were acquired with the FIES spectrograph at the Nordic Optical Telescope, La Palma. The 5.49d period orbit of BKPeg is slightly eccentric (e=0.053). The two components are quite different with masses and radii of (1.414±0.007M, 1.988±0.008R) and (1.257±0.005M, 1.474±0.017R), respectively. The measured rotational velocities are 16.6±0.2 (primary) and 13.4±0.2 (secondary) km/s. For the secondary component this corresponds to (pseudo)synchronous rotation, whereas the primary component seems to rotate at a slightly lower rate. We derive an iron abundance of [Fe/H]=-0.12±0.07 and similar abundances for Si, Ca, Sc, Ti, Cr and Ni. The stars have evolved to the upper half of the main-sequence band. Yonsei-Yale and Victoria-Regina evolutionary models for the observed metal abundance reproduce BKPeg at ages of 2.75 and 2.50Gyr, respectively, but tend to predict a lower age for the more massive primary component than for the secondary. We find the same age trend for three other upper main-sequence systems in a sample of well studied eclipsing binaries with components in the 1.15-1.70M range. We also find that the Yonsei-Yale models systematically predict higher ages than the Victoria-Regina models. The sample includes BWAqr, and as a supplement we have determined a [Fe/H] abundance of -0.07±0.11 for this late F-type binary. We propose to use BK Peg, BW Aqr, and other well-studied 1.15-1.70M eclipsing binaries to fine-tune convective core overshoot, diffusion, and possibly other ingredients of modern theoretical evolutionary models.

Abstract Copyright:

Journal keyword(s): stars: evolution - stars: fundamental parameters - binaries: eclipsing - stars: individual: BK Peg - stars: individual: BW Aqr - techniques: spectroscopic

VizieR on-line data: <Available at CDS (J/A+A/516/A42): table13.dat table14.dat table15.dat table16.dat table17.dat>

Simbad objects: 16

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Number of rows : 16
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 V* AI Phe SB* 01 09 34.1924055096 -46 15 56.071719360   9.26 8.60     G3V 140 0
2 V* V570 Per SB* 03 09 34.9441274976 +48 37 28.696544364   8.55 8.09     F5 48 0
3 V* V1130 Tau SB* 03 50 41.9411242656 +01 33 50.219292672   7.03 6.66     F2V 59 0
4 V* GX Gem EB* 06 46 09.1272024000 +34 24 52.792971336   11.99 11.71     G5 59 0
5 V* FS Mon EB* 07 24 42.3029495064 -05 09 14.553350424   10.07 9.68     F2 42 0
6 HD 71636 SB* 08 29 56.3117926560 +37 04 15.482319600   8.30 7.90     F5 44 0
7 V* VZ Hya EB* 08 31 41.4131992848 -06 19 07.563903420   9.48 9.06     F3/5V 109 0
8 NGC 2680 ** 08 51 33.5 +30 51 56           ~ 1 1
9 V* AD Boo EB* 14 35 12.7797940752 +24 38 21.323757120   9.95 9.44     G0 66 0
10 IC 4651 OpC 17 24 51 -49 55.0           ~ 339 0
11 V* V442 Cyg EB* 20 27 52.3040139552 +30 47 28.346913456   10.18 9.70     F2 71 0
12 V* BW Aqr SB* 22 23 15.9305850720 -15 19 56.201783268   10.8 10.3     F7 101 0
13 HD 222249 PM* 23 38 49.5007524408 +23 18 29.974196340   7.61 7.14     F5IV 26 0
14 HD 222391 PM* 23 40 03.4151170344 +26 48 07.153378380   8.10   7.2   G0III 33 0
15 V* BK Peg SB* 23 47 08.4664310208 +26 33 59.970121200   10.46 10.04     F8 74 0
16 HD 223323 SB* 23 48 31.4619041664 +25 39 13.796632044 7.410 7.490 7.070     F2IV-V 47 0

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2023.01.27-17:58:34

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