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Title: AN EXPANDED VERY LARGE ARRAY AND CARMA STUDY OF DUSTY DISKS AND TORII WITH LARGE GRAINS IN DYING STARS

Abstract

We report the results of a pilot multiwavelength survey in the radio continuum (X, Ka, and Q bands, i.e., from 3.6 cm to 7 mm) carried out with the Expanded Very Large Array (EVLA) in order to confirm the presence of very large dust grains in dusty disks and torii around the central stars in a small sample of post-asymptotic giant branch (pAGB) objects, as inferred from millimeter (mm) and submillimeter (submm) observations. Supporting mm-wave observations were also obtained with the Combined Array for Research in Millimeter-wave Astronomy toward three of our sources. Our EVLA survey has resulted in a robust detection of our most prominent submm emission source, the pre-planetary nebula (PPN) IRAS 22036+5306, in all three bands, and the disk-prominent pAGB object, RV Tau, in one band. The observed fluxes are consistent with optically thin free-free emission, and since they are insignificant compared to their submm/mm fluxes, we conclude that the latter must come from substantial masses of cool, large (mm-sized) grains. We find that the power-law emissivity in the cm-to-submm range for the large grains in IRAS22036 is {nu}{sup {beta}}, with {beta} = 1-1.3. Furthermore, the value of {beta} in the 3-0.85 mm range for the threemore » disk-prominent pAGB sources ({beta} {<=} 0.4) is significantly lower than that of IRAS22036, suggesting that the grains in pAGB objects with circumbinary disks are likely larger than those in the dusty waists of pre-planetary nebulae.« less

Authors:
 [1];  [2];  [3];  [4];  [5]
  1. Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States)
  2. National Radio Astronomy Observatory, 1003 Lopezville Road, Socorro, NM 87801 (United States)
  3. National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)
  4. Division of Astronomy, Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095 (United States)
  5. Astrobiology Center (CSIC-INTA), ESAC Campus, E-28691 Villanueva de la Canada, Madrid (Spain)
Publication Date:
OSTI Identifier:
21565464
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 739; Journal Issue: 1; Other Information: DOI: 10.1088/2041-8205/739/1/L3; Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; DUSTS; EMISSIVITY; PLANETARY NEBULAE; STARS; NEBULAE; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; SURFACE PROPERTIES

Citation Formats

Sahai, R., Claussen, M. J., Schnee, S., Morris, M. R., and Sanchez Contreras, C., E-mail: raghvendra.sahai@jpl.nasa.gov. AN EXPANDED VERY LARGE ARRAY AND CARMA STUDY OF DUSTY DISKS AND TORII WITH LARGE GRAINS IN DYING STARS. United States: N. p., 2011. Web. doi:10.1088/2041-8205/739/1/L3.
Sahai, R., Claussen, M. J., Schnee, S., Morris, M. R., & Sanchez Contreras, C., E-mail: raghvendra.sahai@jpl.nasa.gov. AN EXPANDED VERY LARGE ARRAY AND CARMA STUDY OF DUSTY DISKS AND TORII WITH LARGE GRAINS IN DYING STARS. United States. doi:10.1088/2041-8205/739/1/L3.
Sahai, R., Claussen, M. J., Schnee, S., Morris, M. R., and Sanchez Contreras, C., E-mail: raghvendra.sahai@jpl.nasa.gov. Tue . "AN EXPANDED VERY LARGE ARRAY AND CARMA STUDY OF DUSTY DISKS AND TORII WITH LARGE GRAINS IN DYING STARS". United States. doi:10.1088/2041-8205/739/1/L3.
@article{osti_21565464,
title = {AN EXPANDED VERY LARGE ARRAY AND CARMA STUDY OF DUSTY DISKS AND TORII WITH LARGE GRAINS IN DYING STARS},
author = {Sahai, R. and Claussen, M. J. and Schnee, S. and Morris, M. R. and Sanchez Contreras, C., E-mail: raghvendra.sahai@jpl.nasa.gov},
abstractNote = {We report the results of a pilot multiwavelength survey in the radio continuum (X, Ka, and Q bands, i.e., from 3.6 cm to 7 mm) carried out with the Expanded Very Large Array (EVLA) in order to confirm the presence of very large dust grains in dusty disks and torii around the central stars in a small sample of post-asymptotic giant branch (pAGB) objects, as inferred from millimeter (mm) and submillimeter (submm) observations. Supporting mm-wave observations were also obtained with the Combined Array for Research in Millimeter-wave Astronomy toward three of our sources. Our EVLA survey has resulted in a robust detection of our most prominent submm emission source, the pre-planetary nebula (PPN) IRAS 22036+5306, in all three bands, and the disk-prominent pAGB object, RV Tau, in one band. The observed fluxes are consistent with optically thin free-free emission, and since they are insignificant compared to their submm/mm fluxes, we conclude that the latter must come from substantial masses of cool, large (mm-sized) grains. We find that the power-law emissivity in the cm-to-submm range for the large grains in IRAS22036 is {nu}{sup {beta}}, with {beta} = 1-1.3. Furthermore, the value of {beta} in the 3-0.85 mm range for the three disk-prominent pAGB sources ({beta} {<=} 0.4) is significantly lower than that of IRAS22036, suggesting that the grains in pAGB objects with circumbinary disks are likely larger than those in the dusty waists of pre-planetary nebulae.},
doi = {10.1088/2041-8205/739/1/L3},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 739,
place = {United States},
year = {2011},
month = {9}
}