Are Giant Planets Forming Around HR 4796A?

Abstract

We have obtained FUSE and HST STIS spectra of HR 4796A, a nearby 8 Myr old main sequence star that possesses a dusty circumstellar disk whose inclination has been constrained from high resolution near-infrared observations to be ~17 deg from edge-on. We searched for circumstellar absorption in the ground states of C II at 1036.3 A, O I at 1039.2 A, Zn II at 2026.1 A, Lyman series H2, and CO (A-X) and failed to detect any of these species. We place upper limits on the column densities and infer upper limits on the gas masses assuming that the gas is in hydrostatic equilibrium, is well-mixed, and has a temperature, Tgas ~ 65 K. Our measurements suggest that this system possesses very little molecular gas. Therefore, we infer an upper limit for the gas:dust ratio (<4.0) assuming that the gas is atomic. We measure less gas in this system than is required to form the envelope of Jupiter.

10 pages, 3 figures (including 1 color figure), accepted for publication in ApJ

References in corpus (12)

• How Observations of Circumstellar Disk Asymmetries Can Reveal Hidden Planets: Pericenter Glow and its Application to the HR 4796 Disk
• NICMOS Imaging of the HR 4796A Circumstellar Disk
• Rotational velocities of A-type stars II. Measurement of vsini in the northern hemisphere
• The FUV spectrum of TW Hya. I. Observations of H${}_2$ Fluorescence
• Mid-infrared Imaging of a Circumstellar Disk Around HR 4796: Mapping the Debris of Planetary Formation
• A dust disk surrounding the young A star HR4796A
• Deep 10 and 18 micron Imaging of the HR 4796A Circumstellar Disk: Transient Dust Particles & Tentative Evidence for a Brightness Asymmetry
• On the gas temperature in circumstellar disks around A stars
• Looking for Pure Rotational H_2 Emission from Protoplanetary Disks
• Modeling the Infrared Emission from the HR 4796A Disk
• Dust Distribution in Gas Disks. A Model for the Ring Around HR 4796A
• The Formation of Planets

Cited by in corpus (17)

• Spitzer IRS Spectroscopy of IRAS-Discovered Debris Disks
• The Last Gasp of Gas Giant Planet Formation: A Spitzer Study of the 5 Myr-old Cluster NGC 2362
• The Rise and Fall of Debris Disks: MIPS Observations of h and chi Persei and the Evolution of Mid-IR Emission from Planet Formation
• The Differential Lifetimes of Protostellar Gas and Dust Disks
• Oligarchic planetesimal accretion and giant planet formation
• Formation of Narrow Dust Rings in Circumstellar Debris Disks
• Mass and Temperature of the TWA 7 Debris Disk
• Molecular hydrogen in the circumstellar environments of Herbig Ae/Be stars probed by FUSE
• Multiband GPI Imaging of the HR 4796A Debris Disk
• A Deep Spitzer Survey of Circumstellar Disks in the Young Double Cluster, h and chi Persei
• The Formation and Dynamics of Super-Earth Planets
• On The Effect of Giant Planets on the Scattering of Parent Bodies of Iron Meteorite from the Terrestrial Planet Region into the Asteroid Belt: A Concept Study
• Super-Earths: A New Class of Planetary Bodies
• Effects of photophoresis on the evolution of transitional circumstellar disks
• Complex Organic Materials in the HR 4796A Disk?
• Photophoretic Structuring of Circumstellar Dust Disks
• Infrared Spectroscopy of HR 4796A's Bright Outer Cometary Ring + Tenuous Inner Hot Dust Cloud