On the Origin of Stochastic, Low-Frequency Photometric Variability in Massive Stars

Abstract

High-precision photometric observations have revealed ubiquitous stochastic low-frequency photometric variability in early type stars. It has been suggested that this variability arises due to either subsurface convection or internal gravity waves launched by the convective core. Here we show that relevant properties of convection in subsurface convective layers correlate very well with the timescale and amplitude of stochastic low-frequency photometric variability, as well as with the amplitude of macroturbulence. We suggest that low-frequency, stochastic photometric variability and surface turbulence in massive stars are caused by the the presence of subsurface convection. We show that an explanation for the observed surface photometric variability and macroturbulence relying on convective core driven internal gravity waves encounters a number of difficulties and seems unlikely to be able to explain the observed trends.

17 pages, 17 figures, accepted for publication in ApJ

References in corpus (27)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Binary interaction dominates the evolution of massive stars
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• Pre-Supernova Evolution of Massive Single and Binary Stars
• Updated Electron-Conduction Opacities: The Impact on Low-Mass Stellar Models
• The connection between stellar granulation and oscillation as seen by the Kepler mission
• Coulomb tunneling for fusion reactions in dense matter: Path integral Monte Carlo versus mean field
• Low-frequency gravity waves in blue supergiants revealed by high-precision space photometry
• The spectroscopic Hertzsprung-Russell diagram
• The IACOB project: III. New observational clues to understand macroturbulent broadening in massive O- and B-type stars
• Variability of OB stars from TESS southern Sectors 1-13 and high-resolution IACOB and OWN spectroscopy
• Photometric detection of internal gravity waves in upper main-sequence stars. II. Combined TESS photometry and high-resolution spectroscopy
• Three-Dimensional Simulations of Massive Stars: I. Wave Generation and Propagation
• Diverse Variability of O and B Stars Revealed from 2-minute Cadence Light Curves in Sectors 1 and 2 of the TESS Mission: Selection of an Asteroseismic Sample
• A FUSE Survey of the Rotation Rates of Very Massive Stars in the Small and Large Magellanic Clouds
• Fully compressible simulations of waves and core convection in main-sequence stars
• Convective envelopes in rotating OB stars
• Impact of rotation on stochastic excitation of gravity and gravito-inertial waves in stars
• MOST detects corotating bright spots on the mid-O type giant ξ Persei
• Low-frequency variability in massive stars: Core generation or surface phenomenon?
• Variability of newly identified B-type stars observed by Kepler
• A model of rotating convection in stellar and planetary interiors: I - convective penetration
• Two-Dimensional Simulations of Internal Gravity Waves in The Radiation Zones of Intermediate-Mass Stars
• Stochastic light variations in hot stars from wind instability: Finding photometric signatures and testing against the TESS data
• Red noise and pulsations in evolved massive stars
• Magnetic inhibition of convection in O star envelopes
• Metallicity dependence of turbulent pressure and macroturbulence in stellar envelopes

Cited by in corpus (13)

• Theory and Diagnostics of Hot Star Mass Loss
• Stochastic Low Frequency Variability in 3-Dimensional Radiation Hydrodynamical Models of Massive Star Envelopes
• An Atlas of Convection in Main-Sequence Stars
• Photometric detection of internal gravity waves in upper main-sequence stars. III. Comparison of amplitude spectrum fitting and Gaussian process regression using celerite2
• Surface Manifestation of Stochastically Excited Internal Gravity Waves
• Synthesizing Spectra from 3D Radiation Hydrodynamic Models of Massive Stars Using Monte Carlo Radiation Transport
• Magnetic Archaeology of Early-Type Stellar Dynamos
• Ultraviolet Spectropolarimetric Diagnostics of Hot Star Magnetospheres
• Five years of BRITE-Constellation photometry of the luminous blue variable P Cygni: properties of the stochastic low-frequency variability
• Automated photometry of $\gamma$ Cassiopeiae:the last roundup
• Asteroseismology: Looking for axions in the red supergiant star Alpha Ori
• Tidally excited oscillations in MACHO 80.7443.1718: Changing amplitudes and frequencies, high-frequency tidally excited mode, and a decrease in the orbital period
• The Properties of Fast Yellow Pulsating Supergiants: FYPS Point the Way to Missing Red Supergiants