CGCS 6306, another X-ray-emitting asymptotic giant branch star confirmed to be a symbiotic binary
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F25%3A10511304" target="_blank" >RIV/00216208:11320/25:10511304 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=72DXvN526z" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=72DXvN526z</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1051/0004-6361/202554671" target="_blank" >10.1051/0004-6361/202554671</a>
Alternative languages
Result language
angličtina
Original language name
CGCS 6306, another X-ray-emitting asymptotic giant branch star confirmed to be a symbiotic binary
Original language description
Context. A number of asymptotic giant branch (AGB) stars are known to exhibit UV excess and/or X-ray emission. These have been considered signposts of a hot white dwarf (WD) companion in a symbiotic system (SySt), but AGB stars are so bright that they easily outshine these companions, thus hampering their detection at optical wavelengths. A recent multi-wavelength investigation on the X-ray-emitting AGB (X-AGB) star Y Gem has confirmed the presence of a WD companion and therefore its SySt nature. Aims. Our goal is to explore the true nature of another X-AGB star, namely CGCS 6306, to investigate whether some objects from this group may in fact be unnoticed SySts with AGB donors. Methods. We analyzed optical spectra and photometric data together with X-ray observations to investigate the properties of the stellar components and accretion process in CGCS 6306. Results. CGCS 6306 is a carbon Mira with a pulsation period of 362 days. Its optical spectrum exhibits the typical saw-shaped features of molecular absorptions in addition to H I and He I recombination and [O I] and [O III] forbidden emission lines. The H alpha line profile is broad, which can be interpreted as evidence for an accretion disk. The X-ray spectrum is hard, which is typical of highly extincted hot plasma emission, and the X-ray luminosity is approximate to 10(32) erg s(-1). Conclusions. The detection of high-excitation optical emission lines and the X-ray properties of CGCS 6306 confirm the presence of a WD companion, making it a bona fide delta-type X-SySt. Its X-ray luminosity is comparable to that of Y Gem, the other X-AGB star confirmed to be a SySt, which was found to exhibit a high accretion rate. The lack of suitable information on the UV and blue optical properties of CGCS 6306, however, precludes a definitive estimate of the accretion rate in this system. Since CGCS 6306 is a carbon Mira, our work adds it to the small group of Galactic carbon SySts.
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
<a href="/en/project/GN24-10608O" target="_blank" >GN24-10608O: Probing the populations of symbiotic stars and related red giant binaries</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
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
699
Issue of the periodical within the volume
cervenec
Country of publishing house
FR - FRANCE
Number of pages
8
Pages from-to
A117
UT code for WoS article
001522098000013
EID of the result in the Scopus database
2-s2.0-105009902612