Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-10-06
Astrophys.J.637:1040-1055,2006
Astronomy and Astrophysics
Astrophysics
Accepted by ApJ
Scientific paper
10.1086/498420
The outer atmosphere of the M supergiant Betelgeuse is puzzling. Published observations of different kinds have shed light on different aspects of the atmosphere, but no unified picture has emerged. They have shown, for example, evidence of a water envelope (MOLsphere) that in some studies is found to be optically thick in the mid-infrared. In this paper, we present high-resolution, mid-infrared spectra of Betelgeuse recorded with the TEXES spectrograph. The spectra clearly show absorption features of water vapor and OH. We show that a spectrum based on a spherical, hydrostatic model photosphere with T_eff = 3600 K, an effective temperature often assumed for Betelgeuse, fails to model the observed lines. Furthermore, we show that published MOLspheres scenarios are unable to explain our data. However, we are able to model the observed spectrum reasonably well by adopting a cooler outer photospheric structure corresponding to T_mod = 3250 K. The success of this model may indicate the observed mid-infrared lines are formed in cool photospheric surface regions. Given the uncertainties of the temperature structure and the likely presence of inhomogeneities, we cannot rule out the possibility that our spectrum could be mostly photospheric, albeit non-classical. Our data put new, strong constraints on atmospheric models of Betelgeuse and we conclude that continued investigation requires consideration of non-classical model photospheres as well as possible effects of a MOLsphere. We show that the mid-infrared water-vapor features have great diagnostic value for the environments of K and M (super-) giant star atmospheres.
Greathouse Thomas K.
Harper Graham M.
Lacy John H.
Richter Matthew Joseph
Ryde Nils
No associations
LandOfFree
Water Vapor on Betelgeuse as Revealed by TEXES High-Resolution 12 Micron Spectra does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Water Vapor on Betelgeuse as Revealed by TEXES High-Resolution 12 Micron Spectra, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Water Vapor on Betelgeuse as Revealed by TEXES High-Resolution 12 Micron Spectra will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-323620