2024-03-28T18:51:40Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1811372022-10-10T10:56:19Zcom_10261_89com_10261_3col_10261_342
Discovery of time variation of the intensity of molecular lines in IRC+10216 in the submillimeter and far-infrared domains
Cernicharo, José
Teyssier, D.
Quintana-Lacaci, G.
Daniel, F.
Agúndez, Marcelino
Velilla Prieto, L.
Decin, L.
Guélin, M.
Encrenaz, P.
García-Lario, P.
Beck, E. de
Barlow, M. J.
Groenewegen, M.A.T.
Neufeld, D.
Pearson, J.
Stars: carbon
Stars: individual (IRC, 10216)
Astrochemistry
Stars: AGB and post-AGB
We report on the discovery of strong intensity variations in the high rotational lines of abundant molecular species toward the archetypical circumstellar envelope of IRC+10216. The observations have been carried out with the Heterodyne Instrument for the Far-Infrared (HIFI) instrument on board Herschel and with the IRAM30 m telescope. They cover several observing periods spreading over three years. The line intensity variations for molecules produced in the external layers of the envelope most likely result from time variations in the infrared pumping rates. We analyze the main implications this discovery has on the interpretation of molecular line emission in the envelopes of Mira-type stars. Radiative transfer calculations must take into account both the time variability of infrared pumping and the possible variation of the dust and gas temperatures with stellar phase in order to reproduce the observation of molecular lines at different epochs. The effect of gas temperature variations with stellar phase could be particularly important for lines produced in the innermost regions of the envelope. Each layer of the circumstellar envelope sees the stellar light radiation with a different lag time (phase). Our results show that this effect must be included in the models. The submillimeter and far infrared lines of asymptotic giant branch stars can no longer be considered as safe intensity calibrators.
2019-05-09T08:43:54Z
2019-05-09T08:43:54Z
2014-11-20
2019-05-09T08:43:54Z
artículo
http://purl.org/coar/resource_type/c_6501
The Astrophysical Journal 796(1): (2014)
2041-8205
http://hdl.handle.net/10261/181137
10.1088/2041-8205/796/1/L21
2041-8213
26722620
en
https://doi.org/10.1088/2041-8205/796/1/L21
Sí
none
Institute of Physics Publishing