Time-dependent spectral-feature variations of stars displaying the B[e] phenomenon

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F13%3A00107092" target="_blank" >RIV/00216224:14310/13:00107092 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/67985815:_____/12:00388462 RIV/00216208:11320/12:10129571 RIV/67985815:_____/13:00421152 RIV/00216208:11320/13:10173968

Výsledek na webu

<a href="https://www.aanda.org/articles/aa/pdf/2013/06/aa17437-11.pdf" target="_blank" >https://www.aanda.org/articles/aa/pdf/2013/06/aa17437-11.pdf</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/201117437" target="_blank" >10.1051/0004-6361/201117437</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Time-dependent spectral-feature variations of stars displaying the B[e] phenomenon

Popis výsledku v původním jazyce

The B[e] phenomenon can be present in stars of different types and at different evolutionary stages. Very extended circumstellar matter prohibits the study of the atmosphere of these stars, since no photospheric lines are usually observed. Standard stellar atmosphere models are thus not applicable when determining stellar parameters. One of a few possibilities for comprehending the nature of these objects is to study their time variations. Unfortunately, almost no set of spectra with an adequate time description is available for these objects. We obtained an extensive set of MWC 342 spectra (102) during the years 2004-2010 in the wavelength interval around the Ha line (6265-6765 angstrom) to focus on the time variability of the spectral lines in this region. We chose MWC 342 from the known stars showing the B[e] phenomenon since, although this star is very bright, its evolutionary status and the role of binarity in the appearance of the B[e] phenomenon are unknown. The time dependence of radial velocities and equivalent widths of emission lines was measured for the Ha line, He I 6678 angstrom, [OI] 6300, 6364 angstrom, Fe II 6318, 6384, 6344 and 6456 angstrom, and Si II 6347, 6371 angstrom. We detected variability in the spectral lines on both short and long time scales. He I 6678 angstrom shows day-to-day changes in its line profile. We observed pure absorption, pure emission, the P Cygni profile, and the inverse P Cygni profile in this line. There are time intervals where this line disappeared. The Ha line also shows considerable changes in its line profile, radial velocities, and equivalent widths. A cycle of about 1560 days was detected in its radial velocities. The detailed description of the variations in MWC 342 spectra reveals its important properties. The inner atmosphere is affected by changes of days, while existing long-term waves are propagated into the outer regions. It is highly probable that the continuum radiation in the visual region is also variable. The inverse P Cygni profile was probably observed when the continuum radiation reached its maximum. These properties indicate the complicated nature of this object. We discuss here a possible explanation of the observations by a stellar wind supported by pulsations.

Název v anglickém jazyce

Time-dependent spectral-feature variations of stars displaying the B[e] phenomenon

Popis výsledku anglicky

The B[e] phenomenon can be present in stars of different types and at different evolutionary stages. Very extended circumstellar matter prohibits the study of the atmosphere of these stars, since no photospheric lines are usually observed. Standard stellar atmosphere models are thus not applicable when determining stellar parameters. One of a few possibilities for comprehending the nature of these objects is to study their time variations. Unfortunately, almost no set of spectra with an adequate time description is available for these objects. We obtained an extensive set of MWC 342 spectra (102) during the years 2004-2010 in the wavelength interval around the Ha line (6265-6765 angstrom) to focus on the time variability of the spectral lines in this region. We chose MWC 342 from the known stars showing the B[e] phenomenon since, although this star is very bright, its evolutionary status and the role of binarity in the appearance of the B[e] phenomenon are unknown. The time dependence of radial velocities and equivalent widths of emission lines was measured for the Ha line, He I 6678 angstrom, [OI] 6300, 6364 angstrom, Fe II 6318, 6384, 6344 and 6456 angstrom, and Si II 6347, 6371 angstrom. We detected variability in the spectral lines on both short and long time scales. He I 6678 angstrom shows day-to-day changes in its line profile. We observed pure absorption, pure emission, the P Cygni profile, and the inverse P Cygni profile in this line. There are time intervals where this line disappeared. The Ha line also shows considerable changes in its line profile, radial velocities, and equivalent widths. A cycle of about 1560 days was detected in its radial velocities. The detailed description of the variations in MWC 342 spectra reveals its important properties. The inner atmosphere is affected by changes of days, while existing long-term waves are propagated into the outer regions. It is highly probable that the continuum radiation in the visual region is also variable. The inverse P Cygni profile was probably observed when the continuum radiation reached its maximum. These properties indicate the complicated nature of this object. We discuss here a possible explanation of the observations by a stellar wind supported by pulsations.

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

2013

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

—

Svazek periodika

554

Číslo periodika v rámci svazku

A143

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

26

Strana od-do

1-26

Kód UT WoS článku

000320444200141

EID výsledku v databázi Scopus

2-s2.0-84879224097