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Title: CHARA/MIRC observations of two M supergiants in Perseus OB1: Temperature, bayesian modeling, and compressed sensing imaging

Two red supergiants (RSGs) of the Per OB1 association, RS Per and T Per, have been observed in the H band using the Michigan Infra-Red Combiner (MIRC) instrument at the CHARA array. The data show clear evidence of a departure from circular symmetry. We present here new techniques specially developed to analyze such cases, based on state-of-the-art statistical frameworks. The stellar surfaces are first modeled as limb-darkened disks based on SATLAS models that fit both MIRC interferometric data and publicly available spectrophotometric data. Bayesian model selection is then used to determine the most probable number of spots. The effective surface temperatures are also determined and give further support to the recently derived hotter temperature scales of RSGs. The stellar surfaces are reconstructed by our model-independent imaging code SQUEEZE, making use of its novel regularizer based on Compressed Sensing theory. We find excellent agreement between the model-selection results and the reconstructions. Our results provide evidence for the presence of near-infrared spots representing about 3%-5% of the stellar flux.
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [4] ; ;  [5] ; ; ; ;  [6] ;  [7] ;  [8]
  1. Department of Astronomy, University of Michigan, 918 Dennison Building, Ann Arbor, MI 48109-1090 (United States)
  2. Sydney Institute for Astrophysics, School of Physics, University of Sydney, NSW 2006 (Australia)
  3. Department of Physics and Astronomy, East Tennessee State University, Box 70652, Johnson City, TN 37614 (United States)
  4. Department of Astronomy and Astrophysics, Penn State University, University Park, PA 16802 (United States)
  5. Department of Physics and Astronomy, University of St. Andrews (United Kingdom)
  6. The CHARA Array, Georgia State University, P.O. Box 3965, Atlanta, GA 30302-3965 (United States)
  7. National Optical Astronomy Observatory, Tucson, AZ 85726-6732 (United States)
  8. CHARA and Department of Physics and Astronomy, Georgia State University, P. O. Box 4106, Atlanta, GA 30302-4106 (United States)
Publication Date:
OSTI Identifier:
22357158
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 785; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; GALAXIES; GIANT STARS; IMAGE PROCESSING; SIMULATION; SPECTROPHOTOMETRY; STARS; STARSPOTS; SYMMETRY