Query : 2005A&A...436..925R

2005A&A...436..925R - Astronomy and Astrophysics, volume 436, 925-931 (2005/6-4)

A quasi-time-dependent radiative transfer model of OH104.9+2.4.


Abstract (from CDS):

We investigate the pulsation-phase dependent properties of the circumstellar dust shell (CDS) of the OH/IR star OH104.9+2.4 based on radiative transfer modeling (RTM) using the code DUSTY. Our previous study concerning simultaneous modeling of the spectral energy distribution (SED) and near-infrared (NIR) visibilities (Riechers et al., 2004A&A...424..165R) has now been extended by means of a more detailed analysis of the pulsation-phase dependence of the model parameters of OH104.9+2.4. In order to investigate the temporal variation in the spatial structure of the CDS, additional NIR speckle interferometric observations in the K' band were carried out 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. Several key parameters of our previous best-fitting model had to be adjusted in order to be consistent with the newly extended amount of observational data. It was found that a simple rescaling of the bolometric flux Fbol is not sufficient to take the variability of the source into account, as the change in optical depth τ over a full pulsation cycle is rather high. On the other hand, the impact of a change in effective temperature Teff on SED and visibility is rather small. However, observations, as well as models for other AGB stars, show the necessity of including a variation of Teff with pulsation phase in the radiative transfer models. Therefore, our new best-fitting model accounts for these changes.

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: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 UCAC4 750-074573 * 22 19 13.4980297968 +59 49 58.379962656       13.30   M0III 1 0
2 RAFGL 2885 OH* 22 19 27.47784 +59 51 21.7080           O-rich 136 0

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