Contemporaneous Observations of $H\alpha$ Luminosities and Photometric Amplitudes for M Dwarfs

Abstract

While many M dwarfs are known to have strong magnetic fields and high levels of magnetic activity, we are still unsure about the properties of their starspots and the origin of their magnetic dynamos. Both starspots and chromospheric heating are generated by the surface magnetic field; they produce photometric variability and Halpha emission, respectively. Connecting brightness variations to magnetic activity therefore provides a means to examine M dwarf magnetism. We survey 30 M dwarfs previously identified as fast rotating stars (Prot < 10 days). We present time-series optical photometry from the Transiting Exoplanet Survey Satellite (TESS) and contemporaneous optical spectra obtained using the Ohio State Multi-Object Spectrograph (OSMOS) on the 2.4m Hiltner telescope at MDM Observatory in Arizona. We measure rotation periods and photometric amplitudes from TESS light curves using Gaussian Processes. From the OSMOS spectra, we calculate the equivalent width of Halpha, and LHalpha/Lbol. We find a weak positive correlation between Halpha luminosity and the semi-amplitude, Rvar p=0.005_{-0.005}^{+0.075}. We also observe short-term variability (between 20-45 minutes) in Halpha equivalent widths and possible enhancement from flares consistent to recent literature.

19 pages, 9 Figures, 2 Tables, Poster Presented at Cool Stars 21, Publication post-copy editing

References in corpus (52)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• The Gaia mission
• The Transiting Exoplanet Survey Satellite
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• Gaia Early Data Release 3: The astrometric solution
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system
• Detection of atmospheric haze on an extrasolar planet: The 0.55 - 1.05 micron transmission spectrum of HD189733b with the Hubble Space Telescope
• The Solar Neighborhood XVII: Parallax Results from the CTIOPI 0.9m Program -- Twenty New Members of the RECONS 10 Parsec Sample
• Large-scale magnetic topologies of late M dwarfs
• Measuring the rotation period distribution of field M-dwarfs with Kepler
• Stellar magnetism: empirical trends with age and rotation
• The H$\alpha$ emission of nearby M dwarfs and its relation to stellar rotation
• Large-scale magnetic topologies of early M dwarfs
• The Kepler Catalog of Stellar Flares
• Inferring probabilistic stellar rotation periods using Gaussian processes
• Magnetic Cycles and Rotation Periods of Late Type Stars from photometric time series
• Generalized investigation of the rotation-activity relation: Favouring rotation period instead of Rossby number
• Solar-type dynamo behaviour in fully convective stars without a tachocline
• The Solar Neighborhood XLV. The Stellar Multiplicity Rate of M Dwarfs Within 25 pc
• The Occurrence of Rocky Habitable Zone Planets Around Solar-Like Stars from Kepler Data
• Magnetism, rotation, and nonthermal emission in cool stars -- Average magnetic field measurements in 292 M dwarfs
• Analytic Planetary Transit Light Curves and Derivatives for Stars with Polynomial Limb Darkening
• The Factory and The Beehive II. Activity and Rotation in Praesepe and the Hyades
• The Transit Light Source Effect II: The Impact of Stellar Heterogeneity on Transmission Spectra of Planets Orbiting Broadly Sun-like Stars
• On the Inference of a Star's Inclination Angle from its Rotation Velocity and Projected Rotation Velocity
• Flare Statistics for Young Stars from a Convolutional Neural Network Analysis of $\text{TESS}$ Data
• Strong dipole magnetic fields in fast rotating fully convective stars
• Reevaluating the Mass-Radius Relation for Low-Mass, Main Sequence Stars
• CARMENES input catalogue of M dwarfs II. High-resolution imaging with FastCam
• Magnetic fields in M dwarfs from the CARMENES survey
• Relation of X-ray activity and rotation in M dwarfs and predicted time-evolution of the X-ray luminosity
• Time-resolved spectroscopy and photometry of an M dwarf flare star YZ Canis Minoris with OISTER and TESS: Blue asymmetry in H$\alpha$ line during the non-white light flare
• Flare Rates, Rotation Periods. and Spectroscopic Activity Indicators of a Volume-Complete Sample of Mid-to-Late M dwarfs within 15 Parsecs
• Ca II H and K Chromospheric Emission Lines in Late K and M Dwarfs
• Mapping stellar surfaces I: Degeneracies in the rotational light curve problem
• Exploring the M-dwarf Luminosity--Temperature--Radius Relationships using Gaia DR2
• The Volume-Complete Sample of M Dwarfs with Masses 0.1 <= M/M_sol <= 0.3 within 15 Parsecs
• Galactic Kinematics and Observed Flare Rates of a Volume-Complete Sample of Mid-to-Late M-dwarfs: Constraints on the History of the Stellar Radiation Environment of Planets Orbiting Low-mass Stars
• Persistent starspot signals on M dwarfs: multi-wavelength Doppler observations with the Habitable-zone Planet Finder and Keck/HIRES
• The CARMENES search for exoplanets around M dwarfs: Convective shift and starspot constraints from chromatic radial velocities
• The Rotation-Activity Correlations in K and M dwarfs. II. New constraints on the dynamo mechanisms in late-K and M dwarfs before and at the transition to complete convection
• TESS Hunt for Young and Maturing Exoplanets (THYME) VII : Membership, rotation, and lithium in the young cluster Group-X and a new young exoplanet
• Forward modelling of Kepler-band variability due to faculae and spots
• The Ca II H&K Rotation-Activity Relation in 53 mid-to-late type M-Dwarfs
• Association of Plages With Sunspots: A multi wavelength Study Using Kodaikanal Ca $\text{II}$ K and Greenwich sunspot area Data
• Variability Timescales of H$\alpha$ on Active Mid-to-Late M dwarfs
• A Knee-Point in the Rotation-Activity Scaling of Late-type Stars with a Connection to Dynamo Transitions
• Stellar activity with LAMOST. III. Temporal variability pattern in Pleiades, Praesepe, and Hyades
• A Study of the Magnetic Activity and Variability of GJ 436
• FUMES III: Ultraviolet and Optical Variability of M Dwarf Chromospheres
• A Hot Saturn Near (but unassociated with) the Open Cluster NGC 1817

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• Magnetic activity of red giants: correlation between the amplitude of solar-like oscillations and chromospheric indicators
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• Quantifying the Effect of Short-timescale Stellar Activity Upon Transit Detection in M Dwarfs
• HiPERCAM and TESS observations of the rapidly rotating M7V star LP 89--187