Resolving the Inner Cavity of the HD 100546 Disk: A Candidate Young Planetary System?

Details Resolving the Inner Cavity of the HD 100546 Disk: A Candidate Young Planetary System? Resolving the Inner Cavity of the HD 100546 Disk: A Candidate Young Planetary System?

Feb 2005

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005apj...620..470g&link_type=abstract

The Astrophysical Journal, Volume 620, Issue 1, pp. 470-480.

Astronomy and Astrophysics

Astronomy

30

Stars: Circumstellar Matter, Stars: Planetary Systems: Protoplanetary Disks, Stars: Individual: Henry Draper Number: Hd 100546, Stars: Pre-Main-Sequence

Scientific paper

The inner 100 AU of HD 100546 is studied via far-ultraviolet long-slit spectroscopy with the Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS). The star is surrounded by reflection nebulosity, which can be traced 100 AU in the continuum, and by emission from H I Lyα, N I, Si II, and fluorescent H2 transitions. The Lyα emission can be traced up to 200 AU along the system semimajor axis and 300 AU along the semiminor axis. The radial surface brightness profile and the presence of both reflection nebulosity and molecular gas suggest that we have detected the flared surface of the disk predicted from analysis of the IR spectral energy distribution. When corrected for the r-2 falloff in illumination from the Herbig Be star, the reflection nebulosity, neutral atomic gas, and H2 emission all reveal the presence of a central cavity extending 0.13"+/-0.025" (13 AU) from the star, more than 20 times larger in radius than would be expected from dust sublimation alone. The reflection nebulosity within the cavity is centered on a location 0.05" (5 AU) to the southeast of the star along the system semimajor axis. The pericenter asymmetry in the cavity is inconsistent with cavity formation by the combined effects of ice sublimation, radiation pressure blowout on small grains, or other disk chemistry that should produce azimuthally symmetric features. The STIS data are also consistent with a current accretion rate onto the Herbig Be star no higher than a few times 10-9 Msolar yr-1, an order of magnitude lower than seen in 5-8 Myr old Herbig Ae stars. The low accretion rate, large cavity, pericenter asymmetry, and deficit of warm dust grain emission observed over 2-8 μm are all consistent with dynamical sculpting of the disk by one or more bodies within the disk. An upper limit to the flux from any chromospherically active, low-mass companion is a factor of 5-10 fainter than AU Mic (M1 Ve; t=12 Myr) at the distance of HD 100546. This upper limit firmly excludes a low-mass stellar companion within the cavity but does not exclude a less active and/or luminous brown dwarf. The absence of similar central clearing in younger Herbig Ae stars suggests that any companion must become externally detectable late in the evolution of the disk, favoring a giant planet as the source of the structure in the HD 100546 disk.
Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

Affiliated with

Also associated with

No associations

Rating

Resolving the Inner Cavity of the HD 100546 Disk: A Candidate Young Planetary System? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Resolving the Inner Cavity of the HD 100546 Disk: A Candidate Young Planetary System?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Resolving the Inner Cavity of the HD 100546 Disk: A Candidate Young Planetary System? will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1748804