A Flaring L5 Dwarf: The Nature of HαEmission in Very Low Mass (Sub)Stellar Objects

Abstract

Time series spectrophotometry of the L5 dwarf 2MASS 01443536-0716142 showed strong Hαemission which declined by nearly 75% in four consecutive exposures. The line was not detected in emission on a spectrum obtained eleven months later. This behavior constrasts with that of 2MASSI J1315309-264951, an L5 dwarf which has shown even stronger Hαemission on four separate occasions. The observational database suggests that L dwarfs can be found in such strong flares only occasionally, with a duty cycle of order 1%. In contrast, the few, continuously-strong Hαemitters, including PC 0025+0447 and 2MASSI J1237392+652615, must either be (1) objects no older than 10-100 Myrs with continuously-active accretion and/or chromospheres, but which apparently formed in isolation from known young stellar clusters and associations, or (2) objects empowered by a different and unknown mechanism for the Hαenergy.

11 pages, 2 figures, Astronomical Journal in press -- Jan 2003 issue

References in corpus (1)

• Discovery of a very cool object with extraordinarily strong H(alpha) emission

Cited by in corpus (88)

• Meeting the Cool New Neighbors V: A 2MASS-Selected Sample of Ultracool Dwarfs
• Binarity in Brown Dwarfs: T Dwarf Binaries Discovered with the Hubble Space Telescope WPFC2
• SDSS DR7 White Dwarf Catalog
• Fundamental Parameters and Spectral Energy Distributions of Young and Field Age Objects with Masses Spanning the Stellar to Planetary Regime
• Meeting the Cool Neighbors. IX. The Luminosity Function of M7-L8 Ultracool Dwarfs in the Field
• The Brown Dwarf Kinematics Project (BDKP) I. Proper Motions and Tangential Velocities for a Large Sample of Late-type M, L and T Dwarfs
• Chromospheric Activity, Rotation, and Rotational Braking in M and L Dwarfs
• Confirmation of the Electron Cyclotron Maser Instability as the Dominant Source of Radio Emission from Very Low Mass Stars and Brown Dwarfs
• An empirical criterion to classify T Tauri stars and substellar analogs using low-resolution optical spectroscopy
• Radio Observations of a Large Sample of Late-M, L, and T Dwarfs: The Distribution of Magentic Field Strengths
• A Sample of Very Young Field L Dwarfs and Implications for the Brown Dwarf "Lithium Test" at Early Ages
• Large-scale alpha^2-dynamo in low-mass stars and brown dwarfs
• Activity and Kinematics of Ultracool Dwarfs Including An Amazing Flare Observation
• New Low-Mass Members of the Taurus Star-Forming Region
• The Spectra of T Dwarfs. II. Red Optical Data
• Subtle Signatures of Multiplicity in Late-type Dwarf Spectra: The Unresolved M8.5 + T5 Binary 2MASS J03202839-0446358
• The Field Substellar Mass Function Based on the Full-sky 20-pc Census of 525 L, T, and Y Dwarfs
• Rotational Modulation of the Radio Emission from the M9 Dwarf TVLM 513-46546: Broadband Coherent Emission at the Substellar Boundary?
• Preliminary Trigonometric Parallaxes of 184 Late-T and Y Dwarfs and an Analysis of the Field Substellar Mass Function into the "Planetary" Mass Regime
• Photometry and Proper Motions of M, L, and T Dwarfs from the Pan-STARRS1 3$\pi$ Survey
• BOSS Ultracool Dwarfs I: Colors and Magnetic Activity of M and L dwarfs
• Spectroscopic rotational velocities of brown dwarfs
• Measuring Magnetic Fields in Ultracool Stars and Brown Dwarfs
• The Magnetic Properties of an L Dwarf Derived from Simultaneous Radio, X-ray, and H-alpha Observations
• A Volume-Limited Sample of Ultracool Dwarfs. I. Construction, Space Density, and a Gap in the L/T Transition
• Quiescent Radio Emission from Southern Late-type M Dwarfs and a Spectacular Radio Flare from the M8 Dwarf DENIS 1048-3956
• Doppler Imaging of Exoplanets and Brown Dwarfs
• Spectroscopic rotation velocities of L dwarfs from VLT/UVES and their comparison with periods from photometric monitoring
• Atmospheres of Brown Dwarfs
• Discovery of an Unusually Red L-type Brown Dwarf
• Simultaneous Multi-Wavelength Observations of Magnetic Activity in Ultracool Dwarfs. II. Mixed Trends in VB10 and LSR1835+32 and the Possible Role of Rotation
• Simultaneous Multi-Wavelength Observations of Magnetic Activity in Ultracool Dwarfs. I. The Complex Behavior of the M8.5 Dwarf TVLM513-46546
• A Panchromatic View of Brown Dwarf Aurorae
• Ultracool Dwarfs Observed with the Spitzer Infrared Spectrograph. II. Emergence and Sedimentation of Silicate Clouds in L Dwarfs, and Analysis of the Full M5--T9 Field Dwarf Spectroscopic Sample
• Kepler Monitoring of an L Dwarf I. The Photometric Period and White Light Flares
• Detection and high-resolution spectroscopy of a huge flare on the old M9 dwarf DENIS 104814.7-395606.1
• The Hawaii Infrared Parallax Program. IV. A Comprehensive Parallax Survey of L0-T8 dwarfs with UKIRT
• A Survey for H-alpha Emission from Late L dwarfs and T dwarfs
• Simultaneous optical and X-ray observations of a giant flare on the ultracool dwarf LP412-31
• Optical Linear Polarization of Late M- and L-Type Dwarfs
• Photometric variability of young brown dwarfs in the sigma Orionis open cluster
• Parallaxes of Southern Extremely Cool objects (PARSEC) II: Spectroscopic Follow-up and Parallaxes of 52 Targets
• X-ray emission from young brown dwarfs in the Orion Nebula Cluster
• The Ultracool SpeXtroscopic Survey. I. Volume-Limited Spectroscopic Sample and Luminosity Function of M7$-$L5 Ultracool Dwarfs
• GQ Lup B Visible & Near-Infrared Photometric Analysis
• Short-Term H-alpha Variability in M Dwarfs
• The Radio Spectrum of TVLM513-46546: Constraints on the Coronal Properties of a Late M Dwarf
• ASASSN-16ae: A Powerful White-Light Flare on an Early-L Dwarf
• Periodic Optical Variability of Radio Detected Ultracool Dwarfs
• PHOENIX model chromospheres of mid- to late-type M dwarfs
• The First High-Resolution Spectra of 1.3 L Subdwarfs
• Dust in Brown Dwarfs IV. Dust formation and driven turbulence on mesoscopic scales
• Magnetic Field Topology in Low-Mass Stars: Spectropolarimetric Observations of M Dwarfs
• Discovery of Radio Emission from the Tight M8 Binary: LP 349-25
• The ultracool dwarf DENIS-P J104814.7-395606. Chromospheres and coronae at the low-mass end of the main-sequence
• Chromospheric Variability in SDSS M Dwarfs. II. Short-Timescale H-alpha Variability
• The Hyperactive L Dwarf 2MASS J13153094-2649513: Continued Emission and a Brown Dwarf Companion
• Mass Determination and Detection of the Onset of Chromospheric Activity for the Sub-Stellar Object in EF Eridani
• Serendipitous discovery of seven new southern L-dwarfs
• Ultracool Dwarfs Observed with the Spitzer Infrared Spectrograph -- III. Dust Grains in Young L Dwarf Atmospheres Are Heavier
• A new strongly X-ray flaring M9 dwarf in the solar neighborhood
• Multiband photometric detection of a huge flare on the M9 dwarf 2MASSW J1707183+643933
• Hubble Space Telescope Imaging and Spectral Analysis of Two Brown Dwarf Binaries at the L Dwarf/T Dwarf Transition
• Lithium in LP 944-20
• Detection of Radio Emission from the Hyperactive L Dwarf 2MASS J13153094-2649513AB
• Modelling the radio pulses of an ultracool dwarf
• Initial mass function effects on the colour evolution of disk galaxies
• CLOUDS search for variability in brown dwarf atmospheres
• Weather on Other Worlds. IV. H$\alpha$ emission and photometric variability are not correlated in L0$-$T8 dwarfs
• Detection of a giant white-light flare on an L2.5 dwarf with the Next Generation Transit Survey
• Atmospheric electrification in dusty, reactive gases in the solar system and beyond
• Calibrating Ultracool Dwarfs: Optical Template Spectra, Bolometric Corrections, and $\chi$ Values
• Parallaxes of southern extremely cool objects III: 118 L \& T dwarfs
• A new L5 brown dwarf member of the Hyades cluster with chromospheric activity
• Parallaxes of Cool Objects with WISE: Filling in for Gaia
• First spectropolarimetric measurement of a brown dwarf magnetic field in molecular bands
• Magnetic fields in M dwarfs: rapid magnetic field variability in EV Lac
• Hunting for brown dwarf binaries and testing atmospheric models with X-Shooter
• X-ray emission from a brown dwarf in the Pleiades
• Strong H$\alpha$ emission in the young planetary mass companion 2MASS J0249-0557 c
• Contemporaneous Observations of $H\alpha$ Luminosities and Photometric Amplitudes for M Dwarfs
• J-PLUS: Discovery and characterisation of ultracool dwarfs using Virtual Observatory tools II. Second data release and machine learning methodology
• At the Bottom of the Main Sequence: Activity and magnetic fields beyond the threshold to complete convection
• Infrared observations of a mid-L dwarf with strong H$\alpha$ emission
• Short-term spectroscopic monitoring of two cool dwarfs with strong magnetic fields
• CaII and H$\alpha$ flaring M dwarfs detected with multi-filter photometry
• Using Old and New Approaches: Determining Physical Properties of Brown Dwarfs with Empirical Relations and Machine Learning Models
• SpeX Spectroscopy of Unresolved Very Low-Mass Binaries. I. Identification of Seventeen Candidate Binaries Straddling the L Dwarf/T Dwarf Transition