Utilizza questo identificativo per citare o creare un link a questo documento:
http://hdl.handle.net/20.500.12386/29877
Titolo: | A warm molecular ring in AG Car: composing the mass-loss puzzle | Autori: | Bordiu, C. BUFANO, FILOMENA Cerrigone, L. UMANA, Grazia Maria Gloria Rizzo, J. R. BUEMI, CARLA SIMONA LETO, PAOLO Cavallaro, Francesco INGALLINERA, Adriano LORU, SARA TRIGILIO, CORRADO RIGGI, Simone |
Data pubblicazione: | 2020 | Rivista: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Numero: | 500 | Fascicolo: | 4 | Da pagina:: | 5500 | Abstract: | We present APEX observations of CO J=3-2 and ALMA observations of CO J=2-1, 13CO J=2-1 and continuum toward the galactic luminous blue variable AG Car. These new observations reveal the presence of a ring-like molecular structure surrounding the star. Morphology and kinematics of the gas are consistent with a slowly expanding torus located near the equatorial plane of AG Car. Using non-LTE line modelling, we derived the physical parameters of the gas, which is warm (50 K) and moderately dense (10$^3$ cm$^{-3}$. The total mass of molecular gas in the ring is 2.7$\pm$0.9 solar masses. We analysed the radio continuum map, which depicts a point-like source surrounded by a shallow nebula. From the flux of the point-like source, we derived a current mass-loss date of $1.55\pm0.21\times10^{-5}$ solar masses / yr. Finally, to better understand the complex circumstellar environment of AG Car, we put the newly detected ring in relation to the main nebula of dust and ionised gas. We discuss possible formation scenarios for the ring, namely, the accumulation of interstellar material due to the action of the stellar wind, the remnant of a close binary interaction or merger, and an equatorially enhanced mass-loss episode. If molecular gas formed in situ as a result of a mass eruption, it would account for at least a 30$\%$ of the total mass ejected by AG Car. This detection adds a new piece to the puzzle of the complex mass-loss history of AG Car, providing new clues about the interplay between LBV stars and their surroundings. | URI: | http://hdl.handle.net/20.500.12386/29877 | URL: | https://doi.org/10.1093/mnras/staa3606 https://academic.oup.com/mnras/article/500/4/5500/5996198 |
ISSN: | 0035-8711 | DOI: | 10.1093/mnras/staa3606 | Bibcode ADS: | 2021MNRAS.500.5500B | Fulltext: | open |
È visualizzato nelle collezioni: | 1.01 Articoli in rivista |
File in questo documento:
File | Descrizione | Dimensioni | Formato | |
---|---|---|---|---|
bordiu21.pdf | preprint | 1.28 MB | Adobe PDF | Visualizza/apri |
staa3606.pdf | Pdf editoriale | 3.68 MB | Adobe PDF | Visualizza/apri |
Page view(s)
69
controllato il 10-set-2024
Download(s)
33
controllato il 10-set-2024
Google ScholarTM
Check
Altmetric
Altmetric
Tutti i documenti in DSpace sono pubblicati ad Accesso Aperto, salvo diversa indicazione per alcuni documenti specifici.