skip to main content

Title: The physical parameters of the retired a star HD 185351

We report here an analysis of the physical stellar parameters of the giant star HD 185351 using Kepler short-cadence photometry, optical and near infrared interferometry from CHARA, and high-resolution spectroscopy. Asteroseismic oscillations detected in the Kepler short-cadence photometry combined with an effective temperature calculated from the interferometric angular diameter and bolometric flux yield a mean density ρ{sub *} = 0.0130 ± 0.0003 ρ{sub ☉} and surface gravity log g = 3.280 ± 0.011. Combining the gravity and density we find R {sub *} = 5.35 ± 0.20 R {sub ☉} and M {sub *} = 1.99 ± 0.23 M {sub ☉}. The trigonometric parallax and CHARA angular diameter give a radius R {sub *} = 4.97 ± 0.07 R {sub ☉}. This smaller radius, when combined with the mean stellar density, corresponds to a stellar mass 1.60 ± 0.08 M {sub ☉}, which is smaller than the asteroseismic mass by 1.6σ. We find that a larger mass is supported by the observation of mixed modes in our high-precision photometry, the spacing of which is consistent only for M {sub *} ≳ 1.8 M {sub ☉}. Our various and independent mass measurements can be compared to the mass measured from interpolatingmore » the spectroscopic parameters onto stellar evolution models, which yields a model-based mass M {sub *,} {sub model} = 1.87 ± 0.07 M {sub ☉}. This mass agrees well with the asteroseismic value, but is 2.6σ higher than the mass from the combination of asteroseismology and interferometry. The discrepancy motivates future studies with a larger sample of giant stars. However, all of our mass measurements are consistent with HD 185351 having a mass in excess of 1.5 M {sub ☉}.« less
Authors:
 [1] ; ;  [2] ; ;  [3] ;  [4] ;  [5] ; ;  [6]
  1. Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  2. NASA Ames Research Center, Moffett Field, CA 94035 (United States)
  3. Department of Astronomy, Yale University, New Haven, CT 06511 (United States)
  4. Institut für Astrophysik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany)
  5. Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)
  6. Sydney Institute for Astronomy, School of Physics, University of Sydney NSW 2006 (Australia)
Publication Date:
OSTI Identifier:
22370503
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 794; 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; ACCURACY; BOLOMETERS; COMPARATIVE EVALUATIONS; DENSITY; ELEMENT ABUNDANCE; GIANT STARS; GRAVITATION; INTERFEROMETRY; MASS; OSCILLATIONS; PHOTOMETRY; RESOLUTION; SPECTROSCOPY; STAR EVOLUTION; SURFACES