2016A&A...592A..51Q


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.21CET23:54:39

2016A&A...592A..51Q - Astronomy and Astrophysics, volume 592A, 51-51 (2016/8-1)

A λ 3 mm and 1 mm line survey toward the yellow hypergiant IRC +10420 N-rich chemistry and IR flux variations.

QUINTANA-LACACI G., AGUNDEZ M., CERNICHARO J., BUJARRABAL V., SANCHEZ CONTRERAS C., CASTRO-CARRIZO A. and ALCOLEA J.

Abstract (from CDS):

Aims. Our knowledge of the chemical properties of the circumstellar ejecta of the most massive evolved stars is particularly poor. We aim to study the chemical characteristics of the prototypical yellow hypergiant star, IRC +10420. For this purpose, we obtained full line surveys at 1 and 3mm atmospheric windows.
Methods. We have identified 106 molecular emission lines from 22 molecular species. Approximately half of the molecules detected are N-bearing species, in particular HCN, HNC, CN, NO, NS, PN, and N2H+. We used rotational diagrams to derive the density and rotational temperature of the different molecular species detected. We introduced an iterative method that allows us to take moderate line opacities into account.
Results. We have found that IRC +10420 presents high abundances of the N-bearing molecules compared with O-rich evolved stars. This result supports the presence of a N-rich chemistry, expected for massive stars. Our analysis also suggests a decrease of the 12C/13C ratio from ≥7 to ∼3.7 in the last 3800yr, which can be directly related to the nitrogen enrichment observed. In addition, we found that SiO emission presents a significant intensity decrease for high-J lines when compared with older observations. Radiative transfer modeling shows that this variation can be explained by a decrease in the infrared (IR) flux of the dust. The origin of this decrease might be an expansion of the dust shell or a lower stellar temperature due to the pulsation of the star.

Abstract Copyright: © ESO, 2016

Journal keyword(s): molecular processes - circumstellar matter - radio lines: stars - stars: individual: IRC +10420

VizieR on-line data: <Available at CDS (J/A+A/592/A51): list.dat fits/*>

Simbad objects: 8

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Number of rows : 8

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 V* IK Tau Mi* 03 53 28.8884898148 +11 24 21.865959095 16.99 17.03 13.39 7.29 3.20 M7-11 560 0
2 V* VY CMa s*r 07 22 58.32877 -25 46 03.2355 12.01 10.19 7.95     M5Iae 984 0
3 * eta Car Em* 10 45 03.5455050 -59 41 03.951060 6.37 7.034 6.21 4.90 4.41 OBepec 2154 0
4 WRAY 15-1676 pA* 17 19 49.3292317040 -39 10 37.929612963     13.1     ~ 40 1
5 HD 179821 pA* 19 13 58.6083165753 +00 07 31.934676028 10.81 9.694 8.19     G4_0-Ia 217 0
6 IRC +10420 pA* 19 26 48.0981288433 +11 21 16.756524951   13.98 11.66     F8Ia+e 448 0
7 V* CK Vul CV* 19 47 37.93848 +27 18 41.8140           ~ 106 0
8 NGC 7027 PN 21 07 01.8 +42 14 10   9.1 10.9     ~ 2303 1

    Equat.    Gal    SGal    Ecl

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2019.11.21-23:54:39

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