The twin red giant branch system BD+20 5391: A case study of low-mass double-core evolution

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

The twin red giant branch system BD+20 5391: A case study of low-mass double-core evolution

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

The twin red giant branch system BD+20 5391: A case study of low-mass double-core evolution

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

702

Číslo periodika v rámci svazku

Oct.

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

8

Strana od-do

A200

Kód UT WoS článku

001598273800007

EID výsledku v databázi Scopus

2-s2.0-105020015913