The twin red giant branch system BD+20 5391: A case study of low-mass double-core evolution
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00640384" target="_blank" >RIV/67985815:_____/25:00640384 - isvavai.cz</a>
Result on the web
<a href="https://hdl.handle.net/11104/0370792" target="_blank" >https://hdl.handle.net/11104/0370792</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1051/0004-6361/202556201" target="_blank" >10.1051/0004-6361/202556201</a>
Alternative languages
Result language
angličtina
Original language name
The twin red giant branch system BD+20 5391: A case study of low-mass double-core evolution
Original language description
Context. Understanding interactions of binary systems on the red giant branch is crucial to understanding the formation of compact stellar remnants such as helium-core white dwarfs (He-WDs) and hot subdwarfs. However, the detailed evolution of such systems, particularly those with nearly identical components, remains under-explored. Aims. We aim to analyse the double-lined spectroscopic binary system BD+20 5391, composed of two red giant stars, in order to characterise its orbital and stellar parameters and to constrain its evolution. Methods. Spectroscopic data were collected between 2020 and 2025 using the Ondˇrejov Echelle Spectrograph and the Mercator Échelle Spectrograph. The time-resolved spectra were fitted with models to determine the radial velocity curve and derive the system’s parameters. We then used the position of both stars in the Hertzsprung-Russell diagram to constrain the system’s current evolutionary state, and we discuss potential outcomes of future interactions between the binary components. Results. We find that the two stars in BD+20 5391 will likely initiate Roche lobe overflow (RLOF) simultaneously, leading to a double-core evolution scenario. The stars’ helium core masses at RLOF onset will be almost identical, at 0.33 M . This synchronised evolution suggests two possible outcomes: common envelope ejection, resulting in a short-period double He-WD binary, or a merger without envelope ejection. In the former case, the resulting double He-WD may merge later and form a hot subdwarf star. Conclusions. This study provides a valuable benchmark example for understanding the evolution of interacting red giant binaries, which will be discovered in substantial numbers in upcoming large-scale spectroscopic surveys.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10308 - Astronomy (including astrophysics,space science)
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Astronomy & Astrophysics
ISSN
0004-6361
e-ISSN
1432-0746
Volume of the periodical
702
Issue of the periodical within the volume
Oct.
Country of publishing house
FR - FRANCE
Number of pages
8
Pages from-to
A200
UT code for WoS article
001598273800007
EID of the result in the Scopus database
2-s2.0-105020015913