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Photoevaporating stellar envelopes observed with Rayleigh beacon adaptive opticsWe present H-alpha and I-band images of a approximately 1 min diameter field centered on theta(sup 1) C Ori made with a unique adaptive optics system that uses either starlight or Rayleigh-backscattered laser light to correct for atmospheric wavefront distortion. Approximately one-half of the stars in this region are positionally associated with knots of ionized gas, which are interpreted as photoevaporating envelopes of low-mass stars. The acronyms 'partially ionized globule' (PIGs), external ionized (accretion) disks in the environs of radiation sources (EIDERs), or protoplanetary disks (ProPlyDs) all refer to these same knots. The H-alpha fluxes of the PIGs are proportional to their 2 cm radio continumm flux densities, and for nearly all the ionized knots, the 2 cm brightness temperatures are consistent with theta(sup 1) C Ori as the primary source of ionization. The comet-like morphology of the bright nebulosities is modeled as the result of an equilibrium between photoionization, recombination, and shadowing. The radii of the ionized 'head' of the cometary PIGs grow with distance from theta(sup 1) C Ori; the radii range from approximately less than or equal to 0.05 sec to approximately 0.25 sec. We interpret the size-distance relationship as evidence that the envelopes all have the same density profile and mass-loss rate within a factor of 2. Faint, arcuate wisps are observed 1 sec to 2 sec distance from some of the cometary nebulosities; these are modeled as bow shocks caused by the wind from theta(sup 1) C Ori. The positions of the stars associated with the PIGs in the observational H-R diagram indicate they are pre-main-sequence stars with masses less than approximately 3 solar mass, with approximately 1 solar mass being typical. Their medium I-K color is 2.9.
Document ID
19950048262
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Mccullough, P. R.
(Univ. of California, Berkeley, CA United States)
Fugate, R. Q.
(Phillips Lab. Aberdeen, MD, United States)
Christou, J. C.
(Phillips Lab. Aberdeen, MD, United States)
Ellerbroek, B. L.
(Phillips Lab. Aberdeen, MD, United States)
Higgins, C. H.
(Phillips Lab. Aberdeen, MD, United States)
Spinhirne, J. M.
(Rockwell Power Systems, Albuquerque, NM United States)
Cleis, R. A.
(Rockwell Power Systems, Albuquerque, NM United States)
Moroney, J. F.
(Carnegie Mellon Univ. Pittsburgh, PA, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1995
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 438
Issue: 1
ISSN: 0004-637X
Subject Category
Astronomy
Accession Number
95A79861
Funding Number(s)
CONTRACT_GRANT: NAG5-26555
Distribution Limits
Public
Copyright
Other

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