2018ApJ...868..103T


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.20CEST12:02:37

2018ApJ...868..103T - Astrophys. J., 868, 103-103 (2018/December-1)

KIC 2568888: to be or not to be a binary.

THEMESSL N., HEKKER S., MINTS A., GARCIA R.A., GARCIA SARAVIA ORTIZ DE MONTELLANO A., STETSON P.B. and DE RIDDER J.

Abstract (from CDS):

In cases where both components of a binary system show oscillations, asteroseismology has been proposed as a method to identify the system. For KIC 2568888, observed with Kepler, we detect oscillation modes for two red giants in a single power-density spectrum. Through an asteroseismic study we investigate if the stars have similar properties, which could be an indication that they are physically bound into a binary system. While one star lies on the red giant branch (RGB), the other, more evolved star, is either a RGB or asymptotic giant branch star. We found similar ages for the red giants and a mass ratio close to 1. Based on these asteroseismic results, we propose KIC 2568888 as a rare candidate binary system (∼0.1% chance). However, when combining the asteroseismic data with ground-based BVI photometry we estimated different distances for the stars, which we cross-checked with Gaia DR2. From Gaia we obtained for one object a distance between and broadly consistent with the distances from BVI photometry. For the other object we have a negative parallax with a not yet reliable Gaia distance solution. The derived distances challenge a binary interpretation and may either point to a triple system, which could explain the visible magnitudes, or, to a rare chance alignment (∼0.05% chance based on stellar magnitudes). This probability would even be smaller, if calculated for close pairs of stars with a mass ratio close to unity in addition to similar magnitudes, which may indeed indicate that a binary scenario is more favorable.

Abstract Copyright: © 2018. The American Astronomical Society. All rights reserved.

Journal keyword(s): asteroseismology - stars: fundamental parameters - stars: individual: KIC 2568888 - stars: interiors - stars: oscillations including pulsations

Simbad objects: 7

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Number of rows : 7

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 HD 176465 ** 18 58 03.46393 +47 11 30.6471   8.7 8.1     G4V 42 0
2 HD 177412 ** 19 02 39.4182581022 +43 07 02.952679093   8.38 7.86     F6IV 43 0
3 Cl* NGC 6791 SBG 852 * 19 20 22.4114364842 +37 51 41.940601117           ~ 1 0
4 KIC 2568888 RG* 19 20 22.453488 +37 51 41.40828   15.16 13.83 13.42   ~ 5 0
5 Cl* NGC 6791 SBG 867 * 19 20 22.5036047936 +37 51 40.790097691           ~ 1 0
6 NGC 6791 OpC 19 20 53 +37 46.3   10.52 9.5     ~ 840 0
7 HD 190585 EB* 20 03 48.3210976468 +45 36 14.803519667   10.74 9.65     K2 29 0

    Equat.    Gal    SGal    Ecl

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2019.10.20-12:02:37

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