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.

accepted to ApJ, 18 pages, 9 figures

References in corpus (27)

• The NumPy array: a structure for efficient numerical computation
• An Optical Spectroscopic Study of T Tauri Stars. I. Photospheric Properties
• Search for Associations Containing Young stars (SACY): I. Sample & Searching Method
• Spectro-astrometric imaging of molecular gas within protoplanetary disk gaps
• Molecular Gas Clumps from the Destruction of Icy Bodies in the $\beta$ Pictoris Debris Disk
• Accretion Disks around Young Stars: Lifetimes, Disk Locking and Variability
• The CARMENES search for exoplanets around M dwarfs. Activity indicators at visible and near-infrared wavelengths
• The Origins of Fluorescent H2 Emission From T Tauri~Stars
• HD far infrared emission as a measure of protoplanetary disk mass
• The Dust and Gas Around beta Pictoris
• Polycyclic Aromatic Hydrocarbon in Protoplanetary Disks around Herbig Ae/Be and T Tauri Stars
• 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
• 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
• Gas mass tracers in protoplanetary disks: CO is still the best
• Magnetic Properties of Young Stars in the TW Hydrae Association
• Warm Dust around Cool Stars: Field M Dwarfs with WISE 12 or 22 Micron Excess Emission
• A Low-Mass H2 Component to the AU Microscopii Circumstellar Disk
• 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
• 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