2009A&A...503..843G


C.D.S. - SIMBAD4 rel 1.7 - 2020.01.25CET04:14:09

2009A&A...503..843G - Astronomy and Astrophysics, volume 503, 843-854 (2009/9-1)

Analysis of the infrared spectra of the peculiar post-AGB stars EP Lyrae and HD 52961.

GIELEN C., VAN WINCKEL H., MATSUURA M., MIN M., DEROO P., WATERS L.B.F.M. and DOMINIK C.

Abstract (from CDS):

We aim to study in detail the peculiar mineralogy and structure of the circumstellar environment of two binary post-AGB stars, EP Lyr and HD 52961. Both stars were selected from a larger sample of evolved disc sources observed with Spitzer and show unique solid-state and gas features in their infrared spectra. Moreover, they show a very small infrared excess in comparison with the other sample stars. The different dust and gas species are identified on the basis of high-resolution Spitzer-IRS spectra. We fit the full spectrum to constrain grain sizes and temperature distributions in the discs. This, combined with our broad-band spectral energy distribution and interferometric measurements, allows us to study the physical structure of the disc, using a self-consistent 2D radiative-transfer disc model. We find that both stars have strong emission features due to CO2 gas, dominated by 12C16O2, but with clear 13C16O2 and even 16O12C18O isotopic signatures. Crystalline silicates are apparent in both sources but proved very hard to model. EP Lyr also shows evidence of mixed chemistry, with emission features of the rare class-C PAHs. Whether these PAHs reside in the oxygen-rich disc or in a carbon-rich outflow is still unclear. With the strongly processed silicates, the mixed chemistry and the low 12C/13C ratio, EP Lyr resembles some silicate J-type stars, although the depleted photosphere makes nucleosynthetic signatures difficult to probe. We find that the disc environment of both sources is, to a first approximation, well modelled with a passive disc, but additional physics such as grain settling, radial dust distributions, and an outflow component must be included to explain the details of the observed spectral energy distributions in both stars.

Abstract Copyright:

Journal keyword(s): stars: AGB and post-AGB - stars: binaries: general - stars: circumstellar matter - stars: individual: EP Lyrae - stars: individual: HD 52961

Errata: +corrigendum vol. 515, p. C2 (2010)

Simbad objects: 19

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Number of rows : 19

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 MSX SMC 029 pA* 00 36 46.3066254620 -73 31 35.484753395           C-rich 19 0
2 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9184 1
3 V* SU Aur TT* 04 55 59.3861369488 +30 34 01.499800471   10.33 9.30 9.17   G2IIIne 527 0
4 HD 44179 pA* 06 19 58.2185496 -10 38 14.706068 9.51 9.33 9.02     B9Ib/II 709 0
5 V* PS Gem pA* 07 03 39.6306725638 +10 46 13.076555664   7.76 7.37     A0 105 0
6 HD 233517 * 08 22 46.7144627395 +53 04 49.232441095   10.85 9.71     K2 78 0
7 CD-44 4961 pA* 08 56 14.1790943091 -44 43 10.710041643   10.55 9.176     F3e 53 1
8 IRAS 09425-6040 C* 09 44 01.6685286753 -60 54 25.636690927     12.6     C 54 0
9 HD 89353 pA* 10 18 07.5892879413 -28 59 31.194541133   5.76 5.53     B9.5Ib/II 286 0
10 V* V709 Car pA* 10 19 16.8819372679 -57 19 25.874710095   12.71 11.28     G8Ia-0 14 0
11 HD 100764 Pe* 11 35 42.7476806995 -14 35 36.663269333   9.81 8.79 8.08 7.65 C-H2.5 97 0
12 V* RU Cen RV* 12 09 23.8147186123 -45 25 34.813401164   9.81 8.70     G1Ie 86 0
13 IRAS 13416-6243 pA* 13 45 07.2570740611 -62 58 16.832906949           G1I 40 0
14 HD 135344 * 15 15 48.9457954324 -37 08 55.727525343   7.84 7.76     A0V 128 1
15 IRAS 18006-3213 OH* 18 03 52.8258880496 -32 12 59.385021229       12.24 9.71 ~ 34 0
16 V* AC Her pA* 18 30 16.2374666779 +21 52 00.618442618 8.00 7.79 7.01     F4Ibp 315 0
17 V* EP Lyr pA* 19 18 19.5565673262 +27 51 03.077324082   11.22 9.96 10.14   G2II 76 1
18 MSB 38 C* 20 36 07.3863551706 +60 05 26.037276961   13.98 9.86 10.3   C-J4+ 115 0
19 V* V1610 Cyg pA* 21 02 18.27 +36 41 37.0           F5Iae 825 1

    Equat.    Gal    SGal    Ecl

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2020.01.25-04:14:09

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