Detection of H${}_2$ in the TWA 7 System: A Probable Circumstellar Origin

Abstract

Using HST-COS FUV spectra, we have discovered warm molecular hydrogen in the TWA 7 system. TWA 7, a $\sim$9 Myr old M2.5 star, has a cold debris disk and has previously shown no signs of accretion. Molecular hydrogen is expected to be extremely rare in a debris disk. While molecular hydrogen can be produced in star spots or the lower chromospheres of cool stars such as TWA 7, fluxes from progressions that get pumped by the wings of Ly$\alpha$ indicate that this molecular hydrogen could be circumstellar and thus that TWA 7 is accreting at very low levels and may retain a reservoir of gas in the near circumstellar environment.

arXiv commentaccepted to ApJ, 18 pages, 9 figures

References in corpus (82)

• Scikit-learn: Machine Learning in Python
• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• The NumPy array: a structure for efficient numerical computation
• Gaia Data Release 2. Summary of the contents and survey properties
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The SIMBAD astronomical database
• Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
• Protoplanetary Disks and Their Evolution
• Streaming Instabilities in Protoplanetary Disks
• The Disk Substructures at High Angular Resolution Project (DSHARP): I. Motivation, Sample, Calibration, and Overview
• An Optical Spectroscopic Study of T Tauri Stars. I. Photospheric Properties
• Discovery of seven T Tauri stars and a brown dwarf candidate in the nearby TW Hydrae Association
• Eccentricity Evolution for Planets in Gaseous Disks
• Search for Associations Containing Young stars (SACY): I. Sample & Searching Method
• The MUSCLES Treasury Survey II: Intrinsic Lyman Alpha and Extreme Ultraviolet Spectra of K and M Dwarfs with Exoplanets
• Spectro-astrometric imaging of molecular gas within protoplanetary disk gaps
• Accretion Rates for T Tauri Stars Using Nearly Simultaneous Ultraviolet and Optical Spectra
• Molecular Gas Clumps from the Destruction of Icy Bodies in the $\beta$ Pictoris Debris Disk
• The Shape of the Inner Rim in Proto-Planetary Disks
• The MUSCLES Treasury Survey III: X-ray to Infrared Spectra of 11 M and K Stars Hosting Planets
• Survival of molecular gas in cavities of transition disks (I. CO)
• Dust Migration and Morphology in Optically Thin Circumstellar Gas Disks
• The FUV spectrum of TW Hya. I. Observations of H${}_2$ Fluorescence
• A Significantly Low CO Abundance Toward the TW Hya Protoplanetary Disk: A Path to Active Carbon Chemistry?
• The Far-Ultraviolet Spectra of TW Hya. II. Models of H2 Fluorescence in a Disk
• Close Companions to Young Stars. I. A Large Spectroscopic Survey in Chamaeleon I and Taurus-Auriga
• Terrestrial Planet Formation I. The Transition from Oligarchic Growth to Chaotic Growth
• X-Shooter spectroscopy of young stellar objects: II. Impact of chromospheric emission on accretion rate estimates
• Molecular Hydrogen Emission from Protoplanetary Disks
• Formation of sharp eccentric rings in debris disks with gas but without planets
• Accretion Disks around Young Stars: Lifetimes, Disk Locking and Variability
• Exploring Terrestrial Planet Formation in the TW Hydrae Association
• CO rovibrational emission as a probe of inner disk structure
• Self-induced dust traps: overcoming planet formation barriers
• A Far-ultraviolet Atlas of Low-resolution Hubble Space Telescope Spectra of T Tauri Stars
• The CARMENES search for exoplanets around M dwarfs. Activity indicators at visible and near-infrared wavelengths
• A Hubble Space Telescope Survey of H2 Emission in the Circumstellar Environments of Young Stars
• The Origins of Fluorescent H2 Emission From T Tauri~Stars
• Hot Gas Lines in T Tauri Stars
• Observations of T-Tauri Stars using HST-GHRS: I. Far Ultraviolet Emission Lines
• First images of debris disks around TWA 7, TWA 25, HD 35650, and HD 377
• A DEBRIS Disk Around The Planet Hosting M-star GJ581 Spatially Resolved with Herschel
• Detections of Ro-Vibrational H${}_2$ Emission from the Disks of T Tauri Stars
• NUV Excess in Slowly Accreting T Tauri Stars: Limits Imposed by Chromospheric Emission
• HD far infrared emission as a measure of protoplanetary disk mass
• Molecular gas in young debris disks
• Far-Ultraviolet H2 Emission from Circumstellar Disks
• The Dust and Gas Around beta Pictoris
• Polycyclic Aromatic Hydrocarbon in Protoplanetary Disks around Herbig Ae/Be and T Tauri Stars
• Lyman alpha dominance of the Classical T Tauri FUV Radiation Field
• Evolution of X-ray and FUV Disk-Dispersing Radiation Fields
• A Search for Mid-Infrared Molecular Hydrogen Emission from Protoplanetary Disks
• CO/H2 Abundance Ratio ~ 10^{-4} in a Protoplanetary Disk
• The TEXES Survey For H2 Emission From Protoplanetary Disks
• The Herschel DIGIT Survey of Weak-line T Tauri Stars: implications for disk evolution and dissipation
• HST spectra reveal accretion in MY Lupi
• Carbon depletion observed inside T Tauri inner rims: Formation of icy, kilometer size planetesimals by 1 Myr
• On the Ubiquity and Stellar Luminosity Dependence of Exocometary CO Gas: Detection around M Dwarf TWA 7
• Mass and Temperature of the TWA 7 Debris Disk
• Resolving faint structures in the debris disk around TWA7
• Gas mass tracers in protoplanetary disks: CO is still the best
• A Search for Warm Circumstellar Disks in the TW Hydrae Association
• Gas and dust in the TW Hydrae Association as seen by the Herschel Space Observatory
• Magnetic Properties of Young Stars in the TW Hydrae Association
• Detection of submillimeter-wave [C I] emission in gaseous debris disks of 49 Ceti and Beta Pictoris
• Analysis of H2 Emission from Mira B in UV Spectra from HST
• Multiple paths of deuterium fractionation in protoplanetary disks
• Debris Disks Around Nearby Stars with Circumstellar Gas
• A Low-Mass H2 Component to the AU Microscopii Circumstellar Disk
• Warm Dust around Cool Stars: Field M Dwarfs with WISE 12 or 22 Micron Excess Emission
• Unlocking CO Depletion in Protoplanetary Disks II. Primordial C/H Predictions Inside the CO Snowline
• No Transition Disk? Infrared Excess, PAH, H2, and X-rays from the Weak-Lined T Tauri Star DoAr 21
• Rocky Planet Formation: Quick and Neat
• The 1600 Angstrom Emission Bump in Protoplanetary Disks: A Spectral Signature of H${}_2$O Dissociation
• Gas trapping of hot dust around main-sequence stars
• Ultraviolet Spectroscopy of Rapidly-Rotating Solar-Mass Stars: Emission Line Redshifts as a Test of the Solar-Stellar Connection
• FUV Irradiated Disk Atmospheres: Ly$\alpha$ and the Origin of Hot H${}_2$ Emission
• A UV-to-NIR Study of Molecular Gas in the Dust Cavity Around RY Lupi
• FUMES. II. Ly$\alpha$ Reconstructions of Young, Active M Dwarfs
• Long-lived protoplanetary disks in multiple systems: the VLA view of HD 98800
• Sub-millimeter non-contaminated detection of the disk around TWA\,7 by ALMA
• H${}_2$ Fluorescence in M Dwarf Systems: A Stellar Origin

Cited by in corpus (3)

• The Mysterious Affair of the H${}_2$ in AU Mic
• Takeout and Delivery: Erasing the Dusty Signature of Late-stage Terrestrial Planet Formation
• High CO/H2 ratios supports an exocometary origin for a CO-rich debris disk