The masses of retired A stars with asteroseismology: Kepler and K2 observations of exoplanet hosts
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The masses of retired A stars with asteroseismology: Kepler and K2 observations of exoplanet hosts. / North, Thomas S. H.; Campante, Tiago L.; Davies, Guy R.; Grunblatt, Samuel K.; Huber, Daniel; Kuszlewicz, James S.; Lund, Mikkel N.; Cooke, Benjamin F.; Chaplin, William J.; Miglio, Andrea.
In: Royal Astronomical Society. Monthly Notices, Vol. 472, No. 2, 01.12.2017, p. 1866-1878.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - The masses of retired A stars with asteroseismology:
T2 - Kepler and K2 observations of exoplanet hosts
AU - North, Thomas S. H.
AU - Campante, Tiago L.
AU - Davies, Guy R.
AU - Grunblatt, Samuel K.
AU - Huber, Daniel
AU - Kuszlewicz, James S.
AU - Lund, Mikkel N.
AU - Cooke, Benjamin F.
AU - Chaplin, William J.
AU - Miglio, Andrea
PY - 2017/12/1
Y1 - 2017/12/1
N2 - We investigate the masses of ‘retired A stars’ using asteroseismic detections on seven low-luminosity red-giant and sub-giant stars observed by the NASA Kepler and K2 missions. Our aim is to explore whether masses derived from spectroscopy and isochrone fitting may have been systematically overestimated. Our targets have all previously been subject to long-term radial velocity observations to detect orbiting bodies, and satisfy the criteria used by Johnson et al. to select survey stars which may have had A-type (or early F-type) main-sequence progenitors. The sample actually spans a somewhat wider range in mass, from ≈ 1 M⊙ up to ≈ 1.7 M⊙. Whilst for five of the seven stars the reported discovery mass from spectroscopy exceeds the mass estimated using asteroseismology, there is no strong evidence for a significant, systematic bias across the sample. Moreover, comparisons with other masses from the literature show that the absolute scale of any differences is highly sensitive to the chosen reference literature mass, with the scatter between different literature masses significantly larger than reported error bars. We find that any mass difference can be explained through use of different constraints during the recovery process. We also conclude that underestimated uncertainties on the input parameters can significantly bias the recovered stellar masses, which may have contributed to the controversy on the mass scale for retired A stars.
AB - We investigate the masses of ‘retired A stars’ using asteroseismic detections on seven low-luminosity red-giant and sub-giant stars observed by the NASA Kepler and K2 missions. Our aim is to explore whether masses derived from spectroscopy and isochrone fitting may have been systematically overestimated. Our targets have all previously been subject to long-term radial velocity observations to detect orbiting bodies, and satisfy the criteria used by Johnson et al. to select survey stars which may have had A-type (or early F-type) main-sequence progenitors. The sample actually spans a somewhat wider range in mass, from ≈ 1 M⊙ up to ≈ 1.7 M⊙. Whilst for five of the seven stars the reported discovery mass from spectroscopy exceeds the mass estimated using asteroseismology, there is no strong evidence for a significant, systematic bias across the sample. Moreover, comparisons with other masses from the literature show that the absolute scale of any differences is highly sensitive to the chosen reference literature mass, with the scatter between different literature masses significantly larger than reported error bars. We find that any mass difference can be explained through use of different constraints during the recovery process. We also conclude that underestimated uncertainties on the input parameters can significantly bias the recovered stellar masses, which may have contributed to the controversy on the mass scale for retired A stars.
KW - asteroseismology
KW - techniques: photometric
KW - stars: evolution
KW - stars: fundamental parameters
U2 - 10.1093/mnras/stx2009
DO - 10.1093/mnras/stx2009
M3 - Article
VL - 472
SP - 1866
EP - 1878
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -