Evidence of an evolved nature of MWC 349A

The Galactic emission-line object MWC 349A is one of the brightest radio stars in the sky. The central object is embedded in an almost edge-on oriented Keplerian rotating thick disc that seems to drive a rotating bipolar wind. The dense disc is also the site of hot molecular emission such as the CO...

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Detalles Bibliográficos
Autores principales: Kraus, Michaela, Arias, María Laura, Cidale, Lydia Sonia, Torres, Andrea Fabiana
Formato: Articulo
Lenguaje:Inglés
Publicado: 2020
Materias:
Ciencias Astronómicas
stars: massive
stars: emission line, Be
circumstellar matter
stars: individual: MWC 349A
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/123864
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-123864
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
stars: massive
stars: emission line, Be
circumstellar matter
stars: individual: MWC 349A
spellingShingle Ciencias Astronómicas
stars: massive
stars: emission line, Be
circumstellar matter
stars: individual: MWC 349A
Kraus, Michaela
Arias, María Laura
Cidale, Lydia Sonia
Torres, Andrea Fabiana
Evidence of an evolved nature of MWC 349A
topic_facet Ciencias Astronómicas
stars: massive
stars: emission line, Be
circumstellar matter
stars: individual: MWC 349A
description The Galactic emission-line object MWC 349A is one of the brightest radio stars in the sky. The central object is embedded in an almost edge-on oriented Keplerian rotating thick disc that seems to drive a rotating bipolar wind. The dense disc is also the site of hot molecular emission such as the CO bands with its prominent band heads in the near-infrared spectral range. Despite numerous studies, the nature of MWC 349A is still controversial with classifications ranging from a pre-main sequence object to an evolved supergiant. We collected new high-resolution near-infrared spectra in the K- and L-bands using the GNIRS spectrograph at Gemini-North to study the molecular disc of MWC 349A, and in particular to search for other molecular species such as SiO and the isotope 13CO. The amount of 13CO, obtained from the 12CO/13CO ratio, is recognized as an excellent tool to discriminate between pre-main sequence and evolved massive stars. We find no signatures of SiO band emission, but detect CO band emission with considerably lower intensity and CO gas temperature compared to previous observations. Moreover, from detailed modelling of the emission spectrum, we derive an isotope ratio of 12CO/13CO = 4 +- 1. Based on this significant enrichment of the circumstellar environment in 13CO we conclude that MWC 349A belongs to the group of B[e] supergiants, and we discuss possible reasons for the drop in CO intensity.
format Articulo
Articulo
author Kraus, Michaela
Arias, María Laura
Cidale, Lydia Sonia
Torres, Andrea Fabiana
author_facet Kraus, Michaela
Arias, María Laura
Cidale, Lydia Sonia
Torres, Andrea Fabiana
author_sort Kraus, Michaela
title Evidence of an evolved nature of MWC 349A
title_short Evidence of an evolved nature of MWC 349A
title_full Evidence of an evolved nature of MWC 349A
title_fullStr Evidence of an evolved nature of MWC 349A
title_full_unstemmed Evidence of an evolved nature of MWC 349A
title_sort evidence of an evolved nature of mwc 349a
publishDate 2020
url http://sedici.unlp.edu.ar/handle/10915/123864
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bdutipo_str Repositorios
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