2011A&A...529L...3C


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.14CEST17:50:52

2011A&A...529L...3C - Astronomy and Astrophysics, volume 529, L3-3 (2011/5-1)

Probing the dust formation region in IRC +10216 with the high vibrational states of hydrogen cyanide.

CERNICHARO J., AGUNDEZ M., KAHANE C., GUELIN M., GOICOECHEA J.R., MARCELINO N., DE BECK E. and DECIN L.

Abstract (from CDS):

We report the detection in IRC +10216 of 63 rotational transitions of HCN, most of them with quantum numbers J=3-2, pertaining to 28 different vibrational states with energies up to 10700K (ν1+3ν23). Some of the transitions were also observed for the rare isotopologue H13CN. The observations were carried out with the IRAM 30-m telescope. The HCN lines with level energies above 5000K arise within 1.5 stellar radius from the photosphere. Their intensities imply a vibrational temperature of Tvib≃2400K and a fractional HCN abundance relative to H2, x(HCN)=5-7x10–5. These high-energy levels are mainly populated by photospheric radiation, and their vibrational temperature yields a direct measurement of the stellar photospheric temperature. The lines with energy levels between 2000 and 5000K yield Tvib≃1300K and x(HCN)≃0.8-2x10–5. They are radiatively excited and arise from a shell extending between 1.5 and 5 stellar radii. Finally, the lines from the low-energy vibrational states (<2000K) trace a larger region of the envelope (5-28 stellar radii) with Tvib=400-600K and x(HCN)=4-6x10–6. They are strongly affected by mid and near-infrared pumping. The line widths increase from 5km/s near the 2400K photosphere, to 19km/s in the warm 400K shell. This provides a unique insight into the physical conditions of the gas acceleration and dust formation region.

Abstract Copyright:

Journal keyword(s): astrochemistry - line: identification - molecular processes - stars: AGB and post-AGB - circumstellar matter - stars: individual: IRC +10216

Simbad objects: 3

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Number of rows : 3

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 QSO J0854+2006 BLL 08 54 48.8749311881 +20 06 30.642936668   15.91 15.43 15.56   ~ 2000 1
2 IRC +10216 C* 09 47 57.40632 +13 16 43.5648     10.96     C9,5e 2134 0
3 V* RW LMi C* 10 16 02.2834693816 +30 34 18.977096332       15.27   C4,3e 379 0

    Equat.    Gal    SGal    Ecl

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2020.07.14-17:50:52

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