Young intermediate-mass stars in W5 Virtual Observatory Resource

Authors
  1. Koenig X.P.
  2. Allen L.E.
  3. Published by
    CDS
Abstract

We present the results of a survey of young intermediate-mass stars (age<5Myr, 1.5M_{sun}_<M*<=15M_{sun}_) in the W5 massive star-forming region. We use combined optical, near-infrared, and Spitzer Space Telescope photometry and optical spectroscopy to define a sample of stars of spectral types A and B and examine their infrared excess properties. We find objects with infrared excesses characteristic of optically thick disks, i.e., Herbig AeBe stars. These stars are rare: <1.5% of the entire spectroscopic sample of A and B stars, and absent among stars more massive than 2.4M_{sun}_. 7.5% of the A and B stars possess infrared excesses in a variety of morphologies that suggest their disks are in some transitional phase between an initial, optically thick accretion state and later evolutionary states. We identify four morphological classes based on the wavelength dependence of the observed excess emission above theoretical photospheric levels: (1) the optically thick disks; (2) disks with an optically thin excess over the wavelength range 2-24um, similar to that shown by Classical Be stars; (3) disks that are optically thin in their inner regions based on their infrared excess at 2-8um and optically thick in their outer regions based on the magnitude of the observed excess emission at 24um; (4) disks that exhibit empty inner regions (no excess emission at {lambda}<8um) and some measurable excess emission at 24um. A sub-class of disks exhibit no significant excess emission at {lambda}<=5.8um, have excess emission only in the Spitzer 8um band and no detection at 24um. We discuss these spectral energy distribution types, and suggest physical models for disks exhibiting these emission patterns and additional observations to test these theories.

Keywords
  1. infrared-photometry
  2. visible-astronomy
  3. sloan-photometry
  4. stellar-spectral-types
  5. a-stars
  6. young-stellar-objects
  7. emission-line-stars
Bibliographic source Bibcode
2011ApJ...726...18K
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/726/18
IVOA Identifier IVOID
ivo://CDS.VizieR/J/ApJ/726/18
Document Object Identifer DOI
doi:10.26093/cds/vizier.17260018

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History

2012-09-10T14:19:55Z
Resource record created
2012-09-10T14:19:55Z
Created
2017-06-20T13:17:13Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr