2024-03-29T08:23:18Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/274662022-10-20T08:50:28Zcom_10261_44com_10261_4col_10261_297
Warm water vapour in the sooty outflow from a luminous carbon star
Decin, L.
Agúndez, Marcelino
Barlow, Michael J.
Daniel, Fabien
Cernicharo, José
Lombaert, J. R.
Beck, E. de
Royer, P.
Vandenbussche, B.
Wesson, R.
Polehampton, Edward
Blommaert, J. A. D. L.
Meester, W. de
Exter, K.
Feuchtgruber, H.
Gear, W. K.
Gómez, H.L.
Groenewegen, M.A.T.
Guélin, M.
Hargrave, P. C.
Huygen, R.
Imhof, P.
Ivison, R. J.
Jean, C.
Kahane, C.
Kerschbaum, F.
Leeks, S. J.
Lim, T.
Matsuura, M.
Olofsson, G.
Posch, T.
Regibo, S.
Savini, Giovanni
Sibthorpe, B.
Swinyard, B. M.
Yates, J. A.
Waelkens, C.
Astronomy
Astrophysics
The detection1 of circumstellar water vapour around the ageing carbon star IRC +10216 challenged the current understanding of chemistry in old stars, because water was predicted2 to be almost absent in carbon-rich stars. Several explanations for the water were postulated, including the vaporization of icy bodies (comets or dwarf planets) in orbit around the star1, grain surface reactions3, and photochemistry in the outer circumstellar envelope4. With a single water line detected so far from this one carbon-rich evolved star, it is difficult to discriminate between the different mechanisms proposed. Here we report the detection of dozens of water vapour lines in the far-infrared and sub-millimetre spectrum of IRC +10216 using the Herschel satellite5. This includes some high-excitation lines with energies corresponding to ~1,000 K, which can be explained only if water is present in the warm inner sooty region of the envelope. A plausible explanation for the warm water appears to be the penetration of ultraviolet photons deep into a clumpy circumstellar envelope. This mechanism also triggers the formation of other molecules, such as ammonia, whose observed abundances6 are much higher than hitherto predicted7.
2010-09-07T07:32:45Z
2010-09-07T07:32:45Z
2010-09-02
artículo
Nature 467: 64–67 (2010)
0028-0836
http://hdl.handle.net/10261/27466
10.1038/nature09344
1476-4687
eng
http://dx.doi.org/10.1038/nature09344
openAccess
Nature Publishing Group