The Proxima Centauri Campaign -- First Constraints On Millimeter Flare Rates from ALMA

Abstract

Proxima Centauri (Cen) has been the subject of many flaring studies due to its proximity and potential to host habitable planets. The discovery of millimeter flares from this M dwarf with ALMA has opened a new window into the flaring process and the space-weather environments of exoplanets like Proxima b. Using a total of ~50 hours of ALMA observations of Proxima Cen at 1.3 mm (233 GHz), we add a new piece to the stellar flaring picture and report the first cumulative flare frequency distribution (FFD) at millimeter wavelengths of any M dwarf. We detect 463 flares ranging from energies 10${}^{24}$ erg to 10${}^{27}$ erg. The brightest and most energetic flare in our sample reached a flux density of 119 $\pm$ 7 mJy, increasing by a factor of 1000x the quiescent flux, and reaching an energy of 10${}^{27}$ erg in the ALMA bandpass, with t${}_{1/2}$~16s. From a log-log linear regression fit to the FFD, we obtain a power law index of ${\alpha }_{\mathrm{FFD}}$ = 2.92 $\pm$ 0.02, much steeper than ${\alpha }_{\mathrm{FFD}}$ values (~2) observed at X-ray to optical wavelengths. If millimeter flare rates are predictive of flare rates at extreme-UV wavelengths, the contribution of small flares to the radiation environment of Proxima b may be much higher than expected based on the shallower power-law slopes observed at optical wavelengths.

12 pages, 3 figures, 2 tables

References in corpus (50)

• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• A terrestrial planet candidate in a temperate orbit around Proxima Centauri
• The Solar Neighborhood XVII: Parallax Results from the CTIOPI 0.9m Program -- Twenty New Members of the RECONS 10 Parsec Sample
• The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M dwarf
• Kepler Flares I. Active and Inactive M dwarfs
• The Habitability of Planets Orbiting M-dwarf Stars
• Time-Resolved Properties and Global Trends in dMe Flares from Simultaneous Photometry and Spectra
• Modeling Repeated M-dwarf Flaring at an Earth-like Planet in the Habitable Zone: I. Atmospheric Effects for an Unmagnetized Planet
• EUV Flare Activity in Late-Type Stars
• Different Power-law Indices in the Frequency Distributions of Flares with and without Coronal Mass Ejections
• RHESSI Microflare Statistics II. X-ray Imaging, Spectroscopy & Energy Distributions
• Radius Dependent Angular Momentum Evolution in Low-Mass Stars. I
• White-light flares on cool stars in the Kepler Quarter 1 Data
• Kepler Planet Occurrence Rates for Mid-Type M Dwarfs as a Function of Spectral Type
• Acceleration and propagation of Solar Energetic Particles
• From Radio to X-ray: Flares on the dMe Flare Star EV Lacertae
• Rotation of Low-Mass Stars in Upper Scorpius and Rho Ophiuchus with K2
• The MUSCLES Treasury Survey. V. FUV Flares on Active and Inactive M Dwarfs
• A Temporary Epoch of Stalled Spin-Down for Low-Mass Stars: Insights from NGC 6811 with Gaia and Kepler
• Flares from small to large: X-ray spectroscopy of Proxima Centauri with XMM-Newton
• Optical, UV, and X-Ray Evidence for a 7-Year Stellar Cycle in Proxima Centauri
• Millimeter Emission Structure in the first ALMA Image of the AU Mic Debris Disk
• The First Naked-Eye Superflare Detected from Proxima Centauri
• New rotation period measurements for M dwarfs in the southern hemisphere: an abundance of slowly rotating, fully convective stars
• MOST Observations of our Nearest Neighbor: Flares on Proxima Centauri
• Relationship between X-ray and ultraviolet emission of flares from dMe stars observed by XMM-Newton
• Detection of a Millimeter Flare From Proxima Centauri
• The High-Energy Radiation Environment Around a 10 Gyr M Dwarf: Habitable at Last?
• Flare Rates, Rotation Periods. and Spectroscopic Activity Indicators of a Volume-Complete Sample of Mid-to-Late M dwarfs within 15 Parsecs
• A Flare-Type IV Burst Event from Proxima Centauri and Implications for Space Weather
• Discovery of an Extremely Short Duration Flare from Proxima Centauri Using Millimeter through FUV Observations
• LOFAR tied-array imaging of Type III solar radio bursts
• M Dwarf Flare Continuum Variations on One-Second Timescales: Calibrating and Modeling of ULTRACAM Flare Color Indices
• Monitoring the radio emission of Proxima Centauri
• A Very Bright, Very Hot, and Very Long Flaring Event from the M Dwarf Binary System DG CVn
• Flaring activity of Proxima Centauri from TESS observations: quasi-periodic oscillations during flare decay and inferences on the habitability of Proxima b
• Flares in Open Clusters with K2. I. M45 (Pleiades), M44 (Praesepe) and M67
• The periodic variations of a white-light flare observed with ULTRACAM
• The Solar Neighborhood. XXXIV. A Search for Planets Orbiting Nearby M Dwarfs using Astrometry
• 10 Years of Stellar Activity for GJ 1243
• A Seven-Day Multi-Wavelength Flare Campaign on AU Mic I: High-Time Resolution Light Curves and the Thermal Empirical Neupert Effect
• Detection of Galactic and Extragalactic Millimeter-Wavelength Transient Sources with SPT-3G
• NuSTAR Detection of X-Ray Heating Events in the Quiet Sun
• Constraining a Model of Turbulent Coronal Heating for AU Microscopii with X-Ray, Radio, and Millimeter Observations
• Solar flare hard X-ray spikes observed by RHESSI: a case study
• Stellar Flares Are Far-Ultraviolet Luminous
• The Mouse that Squeaked: A small flare from Proxima Cen observed in the millimeter, optical, and soft X-ray with Chandra and ALMA
• First Millimeter Flares Detected from Epsilon Eridani with ALMA
• Nanoflare Heating of the Solar Corona Observed in X-rays

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