Year: 2009
Type: article
Abstract: HD 100453 has an IR spectral energy distribution (SED) which can be fit with a power law plus a blackbody. Previous analysis of the SED suggests that the system is a young Herbig Ae star with a gas-rich, flared disk. We reexamine the evolutionary state of the HD 100453 system by refining its age (based on a candidate low-mass companion) and by examining limits on the disk extent, mass accretion rate, and gas content of the disk environment. We confirm that HD 100453B is a common proper motion companion to HD 100453A, with a spectral type of M4.0V–M4.5V, and derive an age of 10 ± 2 Myr. We find no evidence of mass accretion onto the star. Chandra ACIS-S imagery shows that the Herbig Ae star has L x / L bol and an X-ray spectrum similar to nonaccreting β Pic Moving Group early F stars. Moreover, the disk lacks the conspicuous Fe ii emission and excess FUV continuum seen in spectra of actively accreting Herbig Ae stars, and from the FUV continuum, we find the accretion rate is < 1.4 × 10 −9 M ☉ yr −1 . A sensitive upper limit to the CO J = 3−2 intensity indicates that the gas in the outer disk is likely optically thin. Assuming a [CO]/[H 2 ] abundance of 1 × 10 −4 and a depletion factor of 10 3 , we find that the mass of cold molecular gas is less than ∼0.33 M J and that the gas-to-dust ratio is no more than ∼4:1 in the outer disk. The combination of a high fractional IR excess luminosity, a relatively old age, an absence of accretion signatures, and an absence of detectable circumstellar molecular gas suggests that the HD 100453 system is in an unusual state of evolution between a gas-rich protoplanetary disk and a gas-poor debris disk.
Source: The Astrophysical Journal
Authors: K. A. Collins, C. A. Grady, K. Hamaguchi, J. P. Wisniewski, S. Brittain, M. Sitko, W. J. Carpenter, J. P. Williams, G. S. Mathews, G. M. Williger, R. van Boekel, A. Carmona, Th. Henning, M. E. van den Ancker, G. Meeus, X. P. Chen, R. Petre, B. E. Woodgate
Institutions: University of Louisville, Eureka Scientific, Goddard Space Flight Center, University of Maryland, Baltimore County, University of Washington, Clemson University, University of Cincinnati, University of Hawaiʻi at Mānoa, University of Hawaii System, Johns Hopkins University, Catholic University of America, Max Planck Institute for Astronomy, University of Geneva, European Southern Observatory, Leibniz Institute for Astrophysics Potsdam
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, Smithsonian Institution, National Aeronautics and Space Administration, American Academy of Periodontology Foundation, Kentucky Space Grant Consortium, Johns Hopkins University, Kentucky Science and Engineering Foundation, Kentucky Science and Technology Corporation, Centre National d’Etudes Spatiales, Consejo Nacional de Investigaciones Científicas y Técnicas, Conselho Nacional de Desenvolvimento Científico e Tecnológico, European Southern Observatory, Smithsonian Astrophysical Observatory, Science and Technology Facilities Council, Comisión Nacional de Investigación Científica y Tecnológica
OpenAlex ID: W2073101942