TY - JOUR
T1 - The structure of the prototype bipolar protoplanetary nebula CRL 2688 (EGG Nebula)
T2 - Broadband, polarimetric, and H2 line imaging with NICMOS on the Hubble Space Telescope
AU - Sahai, Raghvendra
AU - Hines, Dean C.
AU - Kastner, Joel H.
AU - Weintraub, David A.
AU - Trauger, John T.
AU - Rieke, Marcia J.
AU - Thompson, Rodger I.
AU - Schneider, Glenn
N1 - Funding Information:
We thank G. Schmidt and D. Lytle for their assistance with the polarimetry reduction and B. Stobie, L. Bergeron, and A. Evans for assistance with data calibration. R. S. and D. C. H. respectively acknowledge support from NASA grants NAS 7-1260 (WFPC2 project) and NAG 5-3042 (NICMOS project). J. H. K.’s research at MIT is supported in part by the Advanced X-Ray Astrophysics Facility Science Center as part of Smith-sonian Astrophysical Observatory contract SVI-61010 under the NASA Marshall Space Flight Center.
PY - 1998
Y1 - 1998
N2 - High-resolution near-infrared (1.65-2.1 μm) images and 2 μm polarimetric images of the inner 19′.5 × 19′.3 region of the bipolar protoplanetary nebula CRL 2688, taken with the newly installed Near-Infrared Camera and Multiobject Spectrometer (NICMOS) aboard the Hubble Space Telescope (HST), are reported. The NICMOS images reveal a wealth of structure also seen in HST Wide Field Planetary Camera 2 images but not detected in previous, ground-based near-infrared imaging studies. In particular, we detect a system of concentric arcs centered on, and twin "searchlight beams" emanating from, the obscured central star. The images also show two sharply bounded spindle-shaped polar cavities with point-symmetric structure, and the 2.122 μm H2 S(1) υ = 1-0 emission-line image clearly resolves the sharp interface between the high-velocity outflow that produces these polar cavities and the surrounding slow outflow that forms the extended nebula. The H2 image also resolves the bright equatorial H2 emission into distinct components and elucidates their detailed morphologies. We have discovered, within the dark lane that bifurcates the bipolar lobes of CRL 2688, a compact source of unpolarized light. Our imaging polarimetry shows that this source is not the post-asymptotic giant branch star that illuminates the nebula; we conclude that the compact source is a companion star.
AB - High-resolution near-infrared (1.65-2.1 μm) images and 2 μm polarimetric images of the inner 19′.5 × 19′.3 region of the bipolar protoplanetary nebula CRL 2688, taken with the newly installed Near-Infrared Camera and Multiobject Spectrometer (NICMOS) aboard the Hubble Space Telescope (HST), are reported. The NICMOS images reveal a wealth of structure also seen in HST Wide Field Planetary Camera 2 images but not detected in previous, ground-based near-infrared imaging studies. In particular, we detect a system of concentric arcs centered on, and twin "searchlight beams" emanating from, the obscured central star. The images also show two sharply bounded spindle-shaped polar cavities with point-symmetric structure, and the 2.122 μm H2 S(1) υ = 1-0 emission-line image clearly resolves the sharp interface between the high-velocity outflow that produces these polar cavities and the surrounding slow outflow that forms the extended nebula. The H2 image also resolves the bright equatorial H2 emission into distinct components and elucidates their detailed morphologies. We have discovered, within the dark lane that bifurcates the bipolar lobes of CRL 2688, a compact source of unpolarized light. Our imaging polarimetry shows that this source is not the post-asymptotic giant branch star that illuminates the nebula; we conclude that the compact source is a companion star.
KW - ISM: reflection nebulae
KW - Stars: AGB and post-AGB
KW - Stars: circumstellar matter
KW - Stars: individual (CRL 2688)
KW - Stars: mass loss
KW - Techniques: polarimetric
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U2 - 10.1086/311108
DO - 10.1086/311108
M3 - Article
AN - SCOPUS:21944434016
VL - 492
SP - L163-L167
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2 PART II
ER -