2008/07/23 by Z. Balog, G. H. Rieke, James Muzerolle +8 · 1 citation
Chemistry · Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Millimeter #Molecular Spectroscopy and Structure #Optics #Photoevaporation #Physics #Planet #Protoplanetary disk #RADIUS #Spectral line #Stars #Stellar, planetary, and galactic studies #T Tauri star #Wavelength #astro-ph
paper · pdf · doi:10.1086/592063
9 pages 5 figures, accepted for publication in ApJ
arxiv created 2008/07/23 · openalex publication_date 2008/11/07 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We present HST NICMOS Paschen α (Paα) images and low- and high-resolution IRS spectra of photoevaporating disk-tail systems originally detected at 24 μm near O stars. We find no Paα emission in any of the systems. The resulting upper limits correspond to about (2–3) × 10 −6 M ☉ of mass in hydrogen in the tails, suggesting that the gas is severely depleted. The IRAC data and the low-resolution 5-12 μm IRS spectra provide evidence for an inner disk, while high-resolution long-wavelength (14-30 μm) IRS spectra confirm the presence of a gas-free tail that consists of ~0.01 to ~1 μm dust grains originating in the outer parts of the circumstellar disks. Overall, our observations support theoretical predictions in which photoevaporation removes the gas relatively quickly (≤10 5 yr) from the outer region of a protoplanetary disk, but leaves an inner, more robust, and possibly gas-rich disk component of radius 5-10 AU. With the gas gone, larger solid bodies in the outer disk can experience a high rate of collisions and produce elevated amounts of dust. This dust is being stripped from the system by the photon pressure of the O star to form a gas-free dusty tail.