2005A&A...436..317P


Query : 2005A&A...436..317P

2005A&A...436..317P - Astronomy and Astrophysics, volume 436, 317-324 (2005/6-2)

Study of molecular layers in the atmosphere of the supergiant star µ Cep by interferometry in the K band.

PERRIN G., RIDGWAY S.T., VERHOELST T., SCHULLER P.A., COUDE DU FORESTO V., TRAUB W.A., MILLAN-GABET R. and LACASSE M.G.

Abstract (from CDS):

Infrared interferometry of supergiant and Mira stars has recently been reinterpreted as revealing the presence of deep molecular layers. Empirical models for a photosphere surrounded by a simple molecular layer or envelope have led to a consistent interpretation of previously inconsistent data. The stellar photospheres are found to be smaller than previously understood, and the molecular layer is much higher and denser than predicted by hydrostatic equilibrium. However, the analysis was based on spatial observations with medium-band optical filters, which mixed the visibilities of different spatial structures. This paper reports spatial interferometry with narrow spectral bands, isolating near-continuum and strong molecular features, obtained for the supergiant µ Cep. The measurements confirm strong variation of apparent diameter across the K-band. A layer model shows that a stellar photosphere of angular diameter 14.11±0.60mas is surrounded by a molecular layer of diameter 18.56±0.26mas, with an optical thickness varying from nearly zero at 2.15µm to >1 at 2.39µm. Although µ Cep and α Ori have a similar spectral type, interferometry shows that they differ in their radiative properties. Comparison with previous broad-band measurements shows the importance of narrow spectral bands. The molecular layer or envelope appears to be a common feature of cool supergiants.

Abstract Copyright:

Journal keyword(s): techniques: interferometric - stars: fundamental parameters - stars: mass-loss - infrared: stars - stars: individual: µ Cep

Simbad objects: 11

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Number of rows : 11
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 * alf Ori s*r 05 55 10.30536 +07 24 25.4304 4.38 2.27 0.42 -1.17 -2.45 M1-M2Ia-Iab 1566 0
2 V* EK Boo LP? 14 46 05.9426993007 +15 07 54.411177125 8.51 7.20 5.63     M5+IIIab 74 0
3 * alf Ser PM* 15 44 16.0743159 +06 25 32.263272 5.080 3.800 2.630 1.82 1.25 K2IIIbCN1 508 0
4 * del Oph PM* 16 14 20.73853 -03 41 39.5612 6.30 4.34 2.75 1.46 0.43 M0.5III 352 0
5 * alf Her ** 17 14 38.85818 +14 23 25.2262   4.51 3.06     M5Ib-II+G5III+F2V: 194 0
6 * del Sge SB* 19 47 23.2655973192 +18 32 03.528856248 6.20 5.23 3.82 2.37 1.08 M2II+B0V 199 0
7 * eta Cep PM* 20 45 17.3755540 +61 50 19.616737 4.960 4.320 3.410 2.76 2.27 K0IV 429 0
8 * eps Cyg ** 20 46 12.6823609 +33 58 12.924926 4.370 3.520 2.480 1.73 1.19 K0III 493 0
9 * mu. Cep s*r 21 43 30.4610574 +58 46 48.160181 8.85 6.43 4.08 1.98 0.22 M2-Ia 648 1
10 * eps Peg LP* 21 44 11.1561394 +09 52 30.031152 5.61 3.91 2.39 1.34 0.58 K2Ib-II 438 0
11 Ass Cep OB 2 As* 21 51 +60.0           ~ 282 0

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2022.07.03-14:13:58

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