Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The impact of winds on the spectral appearance of Red Supergiants   The rate at which mass is lost during the Red Supergiant evolutionary stage
may strongly influence how the star appears. Though there have been many
studies discussing how RSGs appear in the mid and far infrared (IR) as a
function of their mass-loss rate, to date there have been no such
investigations at optical and near-IR wavelengths. In a preliminary study we
construct model atmospheres for RSGs which include a wind, and use these models
to compute synthetic spectra from the optical to the mid-infrared. The
inclusion of a wind has two important effects. Firstly, higher mass-loss rates
result in stronger absorption in the TiO bands, causing the star to appear as a
later spectral type despite its effective temperature remaining constant. This
explains the observed relation between spectral type, evolutionary stage and
mid-IR excess, as well as the mismatch between temperatures derived from the
optical and infrared. Secondly, the wind mimics many observed characteristics
of a `MOLsphere', potentially providing an explanation for the extended
molecular zone inferred to exist around nearby RSGs. Thirdly, we show that wind
fluctuations can explain the spectral variability of Betelgeuse during its
recent dimming, without the need for dust.

8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
19
The categories of this paper are: eess
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga