Hints of the Existence of C-rich Massive Evolved Stars
Artikel i vetenskaplig tidskrift, 2019

We aim to study the properties of a particular type of evolved stars, C-rich evolved stars with high expansion velocities. For this purpose we have focused on the two best studied objects within this group, IRC+10401 and AFGL 2233. We focused on determining their luminosity by studying their spectral energy distribution. Also, we have obtained single-dish line profiles and interferometric maps of the CO J - 1-0 and J = 2-1. emission lines for both objects. We have modeled this emission using a LVG radiative transfer code to determine the kinetic temperature and density profiles of the gas ejected by these stars. We have found that the luminosities obtained for these objects (log(L/L-circle dot). =. 4.1 and 5.4) locate them in the domain of the massive asymptotic giant branch stars (AGBs) and the red supergiant stars (RSGs). In addition, the mass-loss rates obtained (1.5. x. 10(-5)-6. x 10(-3)M(circle dot) yr(-1)) suggest that while IRC+ 10401 might be an AGB star, AFGL 2233 could be an RSG star. All these results, together with those from previous works, suggest that both objects are massive objects, IRC+10401 a massive evolved star with M-init similar to 5-9M(circle dot). which could correspond to an AGB or an RSG and AFGL 2233 an RSG with M-init similar to 20M(circle dot), which would confirm the existence of massive C-rich evolved stars. Two scenarios are proposed to form these types of objects. The first one is capable of producing high-mass AGB stars up to similar to 8M(circle dot). and the second one is capable of forming C-rich RSGs like AFGL 2233.

circumstellar matter

nuclear reactions, nucleosynthesis, abundances

astrochemistry

stars: AGB and post-AGB

supergiants

stars: evolution

Författare

Guillermo Quintana-Lacaci

Consejo Superior de Investigaciones Científicas

Jose Cernicharo

Consejo Superior de Investigaciones Científicas

Marcelino Agundez

Consejo Superior de Investigaciones Científicas

Jose Pablo Fonfria

Consejo Superior de Investigaciones Científicas

Luis Velilla Prieto

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

Carmen Sanchez Contreras

Consejo Superior de Investigaciones Científicas

Valentin Bujarrabal

IGN

Arancha Castro-Carrizo

Instituto de Radio Astronomía Millimétrica

Javier Alcolea

IGN

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 876 2 116

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.3847/1538-4357/ab133e

PubMed

31105315

Mer information

Senast uppdaterat

2019-08-18