2022A&A...666A..18A


Query : 2022A&A...666A..18A

2022A&A...666A..18A - Astronomy and Astrophysics, volume 666A, 18 (2022/10-1)

Constraining the overcontact phase in massive binary evolution II. Period stability of known O+O overcontact systems.

ABDUL-MASIH M., ESCORZA A., MENON A., MAHY L. and MARCHANT P.

Abstract (from CDS):


Context. Given that mergers are often invoked to explain many exotic phenomena in massive star evolution, understanding the evolutionary phase directly preceding a merger, the overcontact phase, is of crucial importance. Despite this, large uncertainties exist in our understanding of the evolution of massive overcontact binaries.
Aims. We aim to provide robust observational constraints on the future dynamical evolution of massive overcontact systems by measuring the rate at which the periods change for a sample of six such objects. Furthermore, we aim to investigate whether the periods of unequal-mass systems show higher rates of change than their equal mass counterparts, as theoretical models predict.
Methods. Using archival photometric data from various ground- and space-based missions covering up to ∼40 years, we measure the periods of each system over several smaller time spans. We then fit a linear regression through the measured periods to determine the rate at which the period is changing over the entire data set.
Results. We find that all of the stars in our sample have very small period changes and that there does not seem to be a correlation with the mass ratio. This implies that the orbital periods for these systems are stable on the nuclear timescale, and that the unequal-mass systems may not equalize as expected.
Conclusions. When comparing our results with population synthesis distributions, we find large discrepancies between the expected mass ratios and period stabilities. We find that these discrepancies can be mitigated to a degree by removing systems with shorter initial periods, suggesting that the observed sample of overcontact systems may originate from binary systems with longer initial orbital periods.

Abstract Copyright: © M. Abdul-Masih et al. 2022

Journal keyword(s): binaries: close - stars: massive - stars: evolution - techniques: photometric

Simbad objects: 15

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Number of rows : 15
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 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 11178 1
2 MOA J010321.3-720538 SB* 01 03 21.3011685264 -72 05 38.152558428 12.06 13.15 13.36   13.95 O6V+O4/5III(f) 25 0
3 SV* HV 1998 EB* 01 05 30.5993409384 -72 01 21.697362012   14.53 14.856   15.028 ~ 15 0
4 BD+56 864 SB* 03 59 18.2933470368 +57 14 13.757279424 10.837 9.93 9.80     O5.5V(n)+O6.5V(n) 50 0
5 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 17478 0
6 HD 35921 ** 05 29 42.6497086888 +35 22 30.097742031 6.23         O9II 243 0
7 SN 1987A SN* 05 35 28.020 -69 16 11.07           SNIIpec 4945 2
8 OGLE BRIGHT-LMC-ECL-9 SB* 05 38 28.4561494056 -69 11 19.130738892   14.28 14.485   14.385 O4.5V(n)((fc)):z:+O5.5V(n)((fc)):z: 36 0
9 HD 269956 WR* 05 40 07.5344560704 -69 24 31.913547048 12.043 13.014 13.166 13.51 13.205 WN2.5-3+B1V+O4V+O6.5V 50 0
10 * 29 CMa SB* 07 18 40.3789353696 -24 33 31.318248528 3.80 4.80 4.95 4.95 5.08 O7Iafpvar 417 0
11 HD 64315 Em* 07 52 20.2841727949 -26 25 46.683038109 8.76 9.49 9.24 9.63 8.86 O5.5Vz+O7V 117 1
12 V* TU Mus SB* 11 31 10.9241479224 -65 44 32.099167788 7.58 9.52 9.34 9.25   O8V(n)z+B0V(n) 171 0
13 V* V889 Cen El* 13 26 59.8293556824 -62 01 49.329912828 12.71 12.81 11.66 11.27   O4f+_+_O6/7:(f:) 27 0
14 V* V382 Cyg SB* 20 18 47.2202814912 +36 20 26.085111756 9.35 9.19 8.65     O6IVn+O5Vn 191 0
15 BD+40 4220 s*b 20 32 22.4238071594 +41 18 18.942475904 11.32 10.61 9.185     O7Iafep 399 0

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