First detection of a magnetic field in low-luminosity B[e] stars New scenarios for the nature and evolutionary stages of FS CMa stars

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F22%3A00555906" target="_blank" >RIV/67985815:_____/22:00555906 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216208:11320/22:10456044 RIV/00216224:14310/22:00125577

Výsledek na webu

<a href="https://doi.org/10.1051/0004-6361/202141016" target="_blank" >https://doi.org/10.1051/0004-6361/202141016</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202141016" target="_blank" >10.1051/0004-6361/202141016</a>

Jazyk výsledku

angličtina

Název v původním jazyce

First detection of a magnetic field in low-luminosity B[e] stars New scenarios for the nature and evolutionary stages of FS CMa stars

Popis výsledku v původním jazyce

We report the first detection of the magnetic field in a star of FS CMa type, a subgroup of objects characterized by the B[e] phenomenon. The split of magnetically sensitive lines in IRAS 17449+2320 determines the magnetic field modulus of 6.2 +/- 0.2 kG. Spectral lines and their variability reveal the presence of a B-type spectrum and a hot continuum source in the visible. The hot source confirms GALEX UV photometry. Because there is a lack of spectral lines for the hot source in the visible, the spectral fitting gives only the lower temperature limit of the hot source, which is 50 000 K, and the upper limit for the B-type star of 11 100 K. The V/R ratio of the H alpha line shows quasiperiodic behavior on timescale of 800 days. We detected a strong red-shifted absorption in the wings of Balmer and O I lines in some of the spectra. The absorption lines of helium and other metals show no, or very small, variations, indicating unusually stable photospheric regions for FS CMa stars. We detected two events of material infall, which were revealed to be discrete absorption components of resonance lines. The discovery of the strong magnetic field together with the Gaia measurements of the proper motion show that the most probable nature of this star is that of a post-merger object created after the binary left its birth cluster. Another possible scenario is a magnetic Ap star around Terminal-Age Main Sequence. On the other hand, the strong magnetic field defies the hypothesis that IRAS 17449+2320 is an extreme classical Be star. Thus, IRAS 17449+2320 provides a pretext for exploring a new explanation of the nature of FS CMa stars or, at least, a group of stars with very similar spectral properties.

Název v anglickém jazyce

First detection of a magnetic field in low-luminosity B[e] stars New scenarios for the nature and evolutionary stages of FS CMa stars

Popis výsledku anglicky

We report the first detection of the magnetic field in a star of FS CMa type, a subgroup of objects characterized by the B[e] phenomenon. The split of magnetically sensitive lines in IRAS 17449+2320 determines the magnetic field modulus of 6.2 +/- 0.2 kG. Spectral lines and their variability reveal the presence of a B-type spectrum and a hot continuum source in the visible. The hot source confirms GALEX UV photometry. Because there is a lack of spectral lines for the hot source in the visible, the spectral fitting gives only the lower temperature limit of the hot source, which is 50 000 K, and the upper limit for the B-type star of 11 100 K. The V/R ratio of the H alpha line shows quasiperiodic behavior on timescale of 800 days. We detected a strong red-shifted absorption in the wings of Balmer and O I lines in some of the spectra. The absorption lines of helium and other metals show no, or very small, variations, indicating unusually stable photospheric regions for FS CMa stars. We detected two events of material infall, which were revealed to be discrete absorption components of resonance lines. The discovery of the strong magnetic field together with the Gaia measurements of the proper motion show that the most probable nature of this star is that of a post-merger object created after the binary left its birth cluster. Another possible scenario is a magnetic Ap star around Terminal-Age Main Sequence. On the other hand, the strong magnetic field defies the hypothesis that IRAS 17449+2320 is an extreme classical Be star. Thus, IRAS 17449+2320 provides a pretext for exploring a new explanation of the nature of FS CMa stars or, at least, a group of stars with very similar spectral properties.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2022

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

659

Číslo periodika v rámci svazku

March

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

27

Strana od-do

A35

Kód UT WoS článku

000762473500006

EID výsledku v databázi Scopus

2-s2.0-85126489765