The hot Gamma-Doradus and Maia stars

Abstract

The hot $\gamma$~Doradus stars have multiple low frequencies characteristic of $\gamma$~Dor or SPB variables, but are located between the red edge of the SPB and the blue edge of the $\gamma$~Dor instability strips where all low-frequency modes are stable in current models of these stars. Though $\delta$~Sct stars also have low frequencies, there is no sign of high frequencies in hot $\gamma$~Dor stars. We obtained spectra to refine the locations of some of these stars in the H-R diagram and conclude that these are, indeed, anomalous pulsating stars. The Maia variables have multiple high frequencies characteristic of $\beta$~Cep and $\delta$~Sct stars, but lie between the red edge of the $\beta$~Cep and the blue edge of the $\delta$~Sct instability strips. We compile a list of all Maia candidates and obtain spectra of two of these stars. Again, it seems likely that these are anomalous pulsating stars which are currently not understood.

arXiv comment10 pages, 8 figures, 2016, MNRAS, 460, 1318

References in corpus (31)

• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• MILES: A Medium resolution INT Library of Empirical Spectra
• Accurate masses and radii of normal stars: modern results and applications
• Kepler Input Catalog: Photometric Calibration and Stellar Classification
• On the use of empirical bolometric corrections for stars
• ULySS: A Full Spectrum Fitting Package
• Scaled solar tracks and isochrones in a large region of the Z-Y plane I. From the ZAMS to the TP-AGB end for 0.15 - 2.5 Mo stars
• Rotation and differential rotation of active Kepler stars
• Sub-surface convection zones in hot massive stars and their observable consequences
• Fundamental parameters and infrared excesses of Hipparcos stars
• Rotation periods of 12 000 main-sequence Kepler stars: Dependence on stellar spectral type and comparison with v sin i observations
• A New Generation of Los Alamos Opacity Tables
• The atmospheric parameters and spectral interpolator for the stars of MILES
• Kepler observations of variability in B-type stars
• Super-Nyquist asteroseismology with the Kepler Space Telescope
• Turbulent convection and pulsation stability of stars - II. Theoretical instability strip for $\delta$ Scuti and $\gamma$ Doradus stars
• Spectroscopic survey of Kepler stars. I. HERMES/Mercator observations of A- and F-type stars
• Pulsation frequency distribution in Delta Scuti stars
• CoRoT's view of newly discovered B-star pulsators: results for 358 candidate B pulsators from the initial run's exoplanet field data
• Results of a Search for gamma Dor and delta Sct Stars with the Kepler Spacecraft
• The Impact of Enhanced Iron Opacity on Massive Star Pulsations: Updated Instability Strips
• A spectroscopic study of southern (candidate) gamma Doradus stars. I. Time series analysis
• Stellar variability in open clusters. I. A new class of variable stars in NGC 3766
• The puzzling new class of variable stars in NGC 3766 : old friend pulsators?
• The B and Be Star Population of NGC 3766
• Multi-object spectroscopy of stars in the CoRoT fields I: Early-type stars in the CoRoT-fields IRa01, LRa01, LRa02
• Spectrum Analysis of Bright Kepler late B- to early F- Stars
• Main-sequence variable stars in young open cluster NGC 1893
• An Unexpected Discovery in the Rich Open Cluster NGC 6819 Using XMM-Newton
• Probable nonradial g-mode pulsation in early A-type stars
• Frequency and spectrum analysis of $\gamma$ Doradus type Kepler target KIC 6462033

Cited by in corpus (21)

• Beyond the Kepler/K2 bright limit: variability in the seven brightest members of the Pleiades
• Rotational modulation in TESS B stars
• Variability of newly identified B-type stars observed by Kepler
• Pulsation among TESS A and B stars and the Maia variables
• Gaia luminosities of pulsating A-F stars in the Kepler field
• TESS observations of Be stars: a new interpretation
• Evidence for spots on hot stars suggests major revision of stellar physics
• A homogeneous spectroscopic analysis of a Kepler legacy sample of dwarfs for gravity-mode asteroseismology
• Observational and Theoretical Studies of 27 $\delta$ Scuti Stars with Investigation of the Period-Luminosity Relation
• Stellar variability in open clusters. II. Discovery of a new period-luminosity relation in a class of fast-rotating pulsating stars in NGC 3766
• Pulsating B stars in the Scorpius-Centaurus Association with TESS
• Variability in the Massive Open Cluster NGC 1817 from K2: A Rich Population of Asteroseismic Red Clump, Eclipsing Binary, and Main Sequence Pulsating Stars
• Candidate eclipsing binary systems with a Delta Scuti star in Northern TESS field
• Period-luminosity relations of fast-rotating B-type stars in the young open cluster NGC3766
• Stellar Spectral Interpolation using Machine Learning
• Analysis of high-resolution FEROS spectroscopy for a sample of variable B-type stars assembled from TESS photometry
• Spectroscopy of hot Gamma Doradus and A-F hybrid Kepler candidates close to the hot border of the Delta Scuti instability strip
• High-Amplitude gamma Doradus Variables
• A study of Pulsation & Rotation in a sample of A-K type stars in the Kepler field
• On possible explanations of pulsations in Maia stars
• An observer's view on the future of asteroseismology