Observed binary populations reflect the Galactic history. Explaining the orbital periodmass ratio relation in wide hot subdwarf binaries.
(2020) In Astronomy and Astrophysics Abstract
 Context. Wide hot subdwarf B (sdB) binaries with mainsequence companions are outcomes of stable mass transfer from evolved red giants. The orbits of these binaries show a strong correlation between their orbital periods and mass ratios. The origins of this correlation have, so far, been lacking a conclusive explanation.
Aims. We aim to find a binary evolution model which can explain the observed correlation.
Methods. Radii of evolved red giants, and hence the resulting orbital periods, strongly depend on their metallicity. We performed a small but statistically significant binary population synthesis study with the binary stellar evolution code MESA. We used a standard model for binary mass loss and a standard... (More)  Context. Wide hot subdwarf B (sdB) binaries with mainsequence companions are outcomes of stable mass transfer from evolved red giants. The orbits of these binaries show a strong correlation between their orbital periods and mass ratios. The origins of this correlation have, so far, been lacking a conclusive explanation.
Aims. We aim to find a binary evolution model which can explain the observed correlation.
Methods. Radii of evolved red giants, and hence the resulting orbital periods, strongly depend on their metallicity. We performed a small but statistically significant binary population synthesis study with the binary stellar evolution code MESA. We used a standard model for binary mass loss and a standard metallicity history of the Galaxy. The resulting sdB systems were selected based on the same criteria as was used in observations and then compared with the observed population.
Results. We have achieved an excellent match to the observed periodmass ratio correlation without explicitly finetuning any parameters. Furthermore, our models produce a very good match to the observed periodmetallicity correlation. We predict several new correlations, which link the observed sdB binaries to their progenitors, and a correlation between the orbital period, metallicity, and core mass for subdwarfs and young lowmass helium white dwarfs. We also predict that sdB binaries have distinct orbital properties depending on whether they formed in the Galactic bulge, thin or thick disc, or the halo.
Conclusions. We demonstrate, for the first time, how the metallicity history of the Milky Way is imprinted in the properties of the observed postmass transfer binaries. We show that Galactic chemical evolution is an important factor in binary population studies of interacting systems containing at least one evolved lowmass (Minit < 1.6 M⊙) component. Finally, we provide an observationally supported model of mass transfer from lowmass red giants onto mainsequence stars. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/9fae528bef474833b73d8b3631bfb766
 author
 Vos, Joris ; Bobrick, Alexey ^{LU} and Vuckovic, Maja
 organization
 publishing date
 2020
 type
 Contribution to journal
 publication status
 published
 subject
 in
 Astronomy and Astrophysics
 article number
 A163
 publisher
 EDP Sciences
 external identifiers

 scopus:85092207261
 ISSN
 14320746
 DOI
 10.1051/00046361/201937195
 project
 Interacting Giants and Compact Stars
 language
 English
 LU publication?
 yes
 id
 9fae528bef474833b73d8b3631bfb766
 alternative location
 https://ui.adsabs.harvard.edu/abs/2020arXiv200305665V/abstract
 date added to LUP
 20200704 22:57:18
 date last changed
 20220418 23:20:33
@article{9fae528bef474833b73d8b3631bfb766, abstract = {{Context. Wide hot subdwarf B (sdB) binaries with mainsequence companions are outcomes of stable mass transfer from evolved red giants. The orbits of these binaries show a strong correlation between their orbital periods and mass ratios. The origins of this correlation have, so far, been lacking a conclusive explanation.<br> <br> Aims. We aim to find a binary evolution model which can explain the observed correlation.<br> <br> Methods. Radii of evolved red giants, and hence the resulting orbital periods, strongly depend on their metallicity. We performed a small but statistically significant binary population synthesis study with the binary stellar evolution code MESA. We used a standard model for binary mass loss and a standard metallicity history of the Galaxy. The resulting sdB systems were selected based on the same criteria as was used in observations and then compared with the observed population.<br> <br> Results. We have achieved an excellent match to the observed periodmass ratio correlation without explicitly finetuning any parameters. Furthermore, our models produce a very good match to the observed periodmetallicity correlation. We predict several new correlations, which link the observed sdB binaries to their progenitors, and a correlation between the orbital period, metallicity, and core mass for subdwarfs and young lowmass helium white dwarfs. We also predict that sdB binaries have distinct orbital properties depending on whether they formed in the Galactic bulge, thin or thick disc, or the halo.<br> <br> Conclusions. We demonstrate, for the first time, how the metallicity history of the Milky Way is imprinted in the properties of the observed postmass transfer binaries. We show that Galactic chemical evolution is an important factor in binary population studies of interacting systems containing at least one evolved lowmass (Minit < 1.6 M⊙) component. Finally, we provide an observationally supported model of mass transfer from lowmass red giants onto mainsequence stars.}}, author = {{Vos, Joris and Bobrick, Alexey and Vuckovic, Maja}}, issn = {{14320746}}, language = {{eng}}, publisher = {{EDP Sciences}}, series = {{Astronomy and Astrophysics}}, title = {{Observed binary populations reflect the Galactic history. Explaining the orbital periodmass ratio relation in wide hot subdwarf binaries.}}, url = {{http://dx.doi.org/10.1051/00046361/201937195}}, doi = {{10.1051/00046361/201937195}}, year = {{2020}}, }