2004A&A...424..165R


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.15CET12:21:40

2004A&A...424..165R - Astronomy and Astrophysics, volume 424, 165-177 (2004/9-2)

High-resolution near-infrared speckle interferometry and radiative transfer modeling of the OH/IR star OH104.9+2.4.

RIECHERS D., BALEGA Y., DRIEBE T., HOFMANN K.-H., MEN'SHCHIKOV A.B. and WEIGELT G.

Abstract (from CDS):

We present near-infrared speckle interferometry of the OH/IR star OH104.9+2.4 in the K' band obtained with the 6m telescope of the Special Astrophysical Observatory (SAO). At a wavelength of λ=2.12µm the diffraction-limited resolution of 74mas was attained. The reconstructed visibility reveals a spherically symmetric, circumstellar dust shell (CDS) surrounding the central star. The visibility function shows that the stellar contribution to the total flux at λ=2.12µm is less than ∼50%, indicating a rather large optical depth of the CDS. The azimuthally averaged 1-dimensional Gaussian visibility fit yields a diameter of 47±3mas (FHWM), which corresponds to 112±13AU for an adopted distance of D=2.38±0.24kpc. To determine the structure and the properties of the CDS of OH104.9+2.4, radiative transfer calculations using the code DUSTY were performed to simultaneously model its visibility and the spectral energy distribution (SED). We found that both the ISO spectrum and the visibility of OH104.9+2.4 can be well reproduced by a radiative transfer model with an effective temperature Teff=2500±500K of the central source, a dust temperature Tin=1000±200K at the inner shell boundary Rin≃9.1R*=25.4AU, an optical depth τ2.2µm=6.5±0.3, and dust grain radii ranging from amin=0.005±0.003µm to amax=0.2±0.02µm with a power law n(a)∝a–3.5. It was found that even minor changes in amax have a major impact on both the slope and the curvature of the visibility function, while the SED shows only minor changes. Our detailed analysis demonstrates the potential of dust shell modeling constrained by both the SED and visibilities.

Abstract Copyright:

Journal keyword(s): radiative transfer - stars: AGB and post-AGB - stars: mass-loss - stars: circumstellar matter - infrared: stars - stars: individual: OH104.9+2.4

Simbad objects: 10

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Number of rows : 10

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 IRC +10011 OH* 01 06 25.9889735162 +12 35 52.890666456   20.7   18.26 14.01 M8 392 0
2 BD+00 444 PM* 02 40 42.8730493225 +01 11 55.239796152 11.847 10.712 9.509 8.769 8.131 K7V 93 0
3 V* CD Cet BY* 03 13 22.9175232961 +04 46 29.343777709   15.61 14.001 13.650   M4.5Ve 102 0
4 HD 22686 * 03 38 55.0927991114 +02 45 48.587632371   7.24 7.22     A0/1V 41 0
5 HD 44179 pA* 06 19 58.2185496 -10 38 14.706068 9.51 9.33 9.02     B9Ib/II 705 0
6 RAFGL 2290 OH* 18 58 30.0947842133 +06 42 57.698061173           ~ 120 0
7 IRC +10420 pA* 19 26 48.0981288433 +11 21 16.756524951   13.98 11.66     F8Ia+e 448 0
8 NML Cyg s*r 20 46 25.5382179476 +40 06 59.396202678   18.64 16.60     M7/8 481 0
9 * zet Cep EB* 22 10 51.2769159 +58 12 04.545587 6.62 4.90 3.35 2.27 1.49 K1.5Ib 259 0
10 NSV 25875 OH* 22 19 27.48 +59 51 21.7           ~ 133 0

    Equat.    Gal    SGal    Ecl

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2019.11.15-12:21:40

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