The B-type Binaries Characterisation Programme I. Orbital solutions for the 30 Doradus population. (arXiv:2107.10170v1 [astro-ph.SR])

The B-type Binaries Characterisation Programme I. Orbital solutions for the 30 Doradus population. (arXiv:2107.10170v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Villasenor_J/0/1/0/all/0/1">J. I. Villase&#xf1;or</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Taylor_W/0/1/0/all/0/1">W. D. Taylor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Evans_C/0/1/0/all/0/1">C. J. Evans</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ramirez_Agudelo_O/0/1/0/all/0/1">O. H. Ram&#xed;rez-Agudelo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sana_H/0/1/0/all/0/1">H. Sana</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Almeida_L/0/1/0/all/0/1">L. A. Almeida</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mink_S/0/1/0/all/0/1">S. E. de Mink</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dufton_P/0/1/0/all/0/1">P. L. Dufton</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Langer_N/0/1/0/all/0/1">N. Langer</a>

We present results from the B-type Binaries Characterisation (BBC) programme,
a multi-epoch spectroscopic study of 88 early B-type binary candidates in the
30 Doradus region of the Large Magellanic Cloud (LMC). From radial-velocity
analysis of 29 observational epochs we confirm the binary status of 64 of our
targets, comprising 50 SB1 and 14 SB2 B-type binaries. A further 20 systems
(classified as SB1*) show clear signs of periodicity but with more tentative
periods. Orbital solutions are presented for these 84 systems, providing the
largest homogeneous sample to date of the binary properties of early B-type
stars. Our derived orbital-period distribution is generally similar to those
for samples of more massive (O-type) binaries in both the LMC and the Galaxy.
This similarity with the properties of the more massive O-type binaries is
important as early B-type stars are expected to account for the majority of
core-collapse supernovae. Differences in the period distributions of the
different samples start to increase above 4 d, and are also present between the
earliest (B0-0.7) and later-type (B1-2.5) systems within the BBC sample,
although further study is required to understand if this is an observational
bias or a real physical effect. We have examined the semi-amplitude velocities
and orbital periods of our sample to identify potential candidates that could
hide compact companions. Comparing with probability distributions of finding
black hole companions to OB-type stars from a recent theoretical study, we have
found 16 binaries in the higher probability region that warrant further study.

We present results from the B-type Binaries Characterisation (BBC) programme,
a multi-epoch spectroscopic study of 88 early B-type binary candidates in the
30 Doradus region of the Large Magellanic Cloud (LMC). From radial-velocity
analysis of 29 observational epochs we confirm the binary status of 64 of our
targets, comprising 50 SB1 and 14 SB2 B-type binaries. A further 20 systems
(classified as SB1*) show clear signs of periodicity but with more tentative
periods. Orbital solutions are presented for these 84 systems, providing the
largest homogeneous sample to date of the binary properties of early B-type
stars. Our derived orbital-period distribution is generally similar to those
for samples of more massive (O-type) binaries in both the LMC and the Galaxy.
This similarity with the properties of the more massive O-type binaries is
important as early B-type stars are expected to account for the majority of
core-collapse supernovae. Differences in the period distributions of the
different samples start to increase above 4 d, and are also present between the
earliest (B0-0.7) and later-type (B1-2.5) systems within the BBC sample,
although further study is required to understand if this is an observational
bias or a real physical effect. We have examined the semi-amplitude velocities
and orbital periods of our sample to identify potential candidates that could
hide compact companions. Comparing with probability distributions of finding
black hole companions to OB-type stars from a recent theoretical study, we have
found 16 binaries in the higher probability region that warrant further study.

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