The Onset of Molecular Hydrogen Emission from Proto–planetary Nebulae

1998 ◽  
Vol 509 (2) ◽  
pp. 728-732 ◽  
Author(s):  
David A. Weintraub ◽  
Tracy Huard ◽  
Joel H. Kastner ◽  
Ian Gatley
Keyword(s):  
Molecular Hydrogen ◽  
Planetary Nebulae ◽  
Hydrogen Emission

The bipolar symmetry of ring-like planetary nebulae: Molecular hydrogen emission from halos

1994 ◽  
Vol 421 ◽  
pp. 600 ◽  
Author(s):  
Joel H. Kastner ◽  
Ian Gatley ◽  
K. M. Merrill ◽  
R. Probst ◽  
David Weintraub
Keyword(s):  
Molecular Hydrogen ◽  
Planetary Nebulae ◽  
Hydrogen Emission

scholarly journals Planetary Nebulae in the UWISH2 Galactic Plane survey

2016 ◽  
Vol 12 (S323) ◽  
pp. 32-35
Author(s):  
T. M. Gledhill ◽  
D. Froebrich
Keyword(s):  
Emission Line ◽  
Molecular Hydrogen ◽  
Galactic Plane ◽  
Planetary Nebulae ◽  
Hydrogen Emission ◽  
Extended Emission

AbstractUWISH2 is the first unbiassed imaging survey of v =1 − 0 S(1) molecular hydrogen emission (λ = 2.122~μm) in the northern Galactic Plane. Here we discuss 284 extended emission line objects which we consider to be candidate planetary or pre-planetary nebulae. Some are clearly associated with known PN, but the majority (60%) have no previous detection. We have classified the objects according to morphology and find 53% are bipolar with half of these being new detections. The remaining objects are mostly elliptical/round (35%), fainter than the median sample flux (4.4 × 10−17 W m−2) and previously undetected (74%).

scholarly journals The Distribution of Molecular Hydrogen in Planetary Nebulae

1987 ◽  
Vol 120 ◽  
pp. 339-340
Author(s):  
J. W. V. Storey ◽  
B. L. Webster ◽  
P. Payne ◽  
M. A. Dopita
Keyword(s):  
Anisotropic Medium ◽  
Stellar Wind ◽  
Planetary Nebula ◽  
Molecular Hydrogen ◽  
Planetary Nebulae ◽  
Morphological Type ◽  
Hydrogen Emission

A correlation has been found between strong molecular hydrogen emission and the morphological type of a planetary nebula. Those with an equatorial toroid and bipolar extensions have H2 1−0 S(1) stronger than Brackett γ. H2 maps of several objects, and NGC 2346 in particular, are consistent with a fast stellar wind interacting with an anisotropic medium.

scholarly journals Kinematics of Molecular Hydrogen Emission from Pre–Planetary Nebulae: RAFGL 2688 and RAFGL 618

2001 ◽  
Vol 546 (1) ◽  
pp. 279-287 ◽  
Author(s):  
Joel H. Kastner ◽  
David A. Weintraub ◽  
Ian Gatley ◽  
LeeAnn Henn
Keyword(s):  
Molecular Hydrogen ◽  
Planetary Nebulae ◽  
Hydrogen Emission

Discovery of Lyα‐pumped Molecular Hydrogen Emission in the Planetary Nebulae NGC 6853 and NGC 3132

2006 ◽  
Vol 644 (2) ◽  
pp. 981-989 ◽  
Author(s):  
R. E. Lupu ◽  
K. France ◽  
S. R. McCandliss
Keyword(s):  
Molecular Hydrogen ◽  
Planetary Nebulae ◽  
Hydrogen Emission

scholarly journals Small-scale structures in planetary nebulae

2017 ◽  
Author(s):  
◽  
Sean P. Baldridge
Keyword(s):  
Molecular Hydrogen ◽  
Planetary Nebulae ◽  
Small Sample ◽  
Molecular Structures ◽  
Small Scale ◽  
Hydrogen Emission ◽  
Scale Structures ◽  
Research Challenge ◽  
Ring Nebulae ◽  
Small Scale Structures

Two planetary nebulae (PNe) were studied in order to investigate small scale molecular structures in planetary nebulae, the survival of which affects the structure and composition of the interstellar medium (ISM) from which the next generation of stars is born. Molecular hydrogen (H[subscript 2]) was used a tracer for molecular emission and its excitation properties used as a probe of shock physics. Previous studies of several planetary nebulae have indicated a relationship between molecular hydrogen and cometary knots as a shielding mechanism allowing for continued survival and formation of the molecule. Our first PN studied, the Dumbbell nebula (NGC 6853), revealed not only H[subscript 2] bearing knots (similar to the Helix and Ring nebulae), but also regions of H[subscript 2] emission which were poorly sculpted or unstructured diffuse regions, unlike previously studied nebulae. The second PN, NGC 2392 has well documented cometary knots, however we find no detection of molecular hydrogen emission from the knots or otherwise making it an outlier among cometary knot bearing planetary nebulae. Both nebula studied in this research challenge current models of H[subscript 2] bearing small scale structures in PNe and indicate a need to expand our rather small sample of such objects so that we may begin to understand the processes behind H[subscript 2] formation, excitation, and its role in cometary knots of the PN as a whole.

Detection of molecular hydrogen emission from five planetary nebulae

1978 ◽  
Vol 219 ◽  
pp. L33 ◽  
Author(s):  
S. Beckwith ◽  
I. Gatley ◽  
S. E. Persson
Keyword(s):  
Molecular Hydrogen ◽  
Planetary Nebulae ◽  
Hydrogen Emission

The Kinematics and Excitation of Molecular Hydrogen Emission in the Planetary Nebula BD +30o3639

1998 ◽  
Vol 498 (1) ◽  
pp. 267-277 ◽  
Author(s):  
D. L. Shupe ◽  
J. E. Larkin ◽  
R. A. Knop ◽  
L. Armus ◽  
K. Matthews ◽  
...  
Keyword(s):  
Planetary Nebula ◽  
Molecular Hydrogen ◽  
Hydrogen Emission

scholarly journals Near–Infrared Imaging of Proto-Planetary Nebulae

1993 ◽  
Vol 155 ◽  
pp. 340-340 ◽  
Author(s):  
R.E.S. Clegg ◽  
N. A. Walton ◽  
M.J. Barlow
Keyword(s):  
Molecular Hydrogen ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Planetary Nebulae ◽  
Agb Stars ◽  
Intermediate Mass ◽  
Preliminary Results ◽  
Near Ir ◽  
Intermediate Mass Stars ◽  
Hydrogen Lines

It is not really known how low and intermediate mass stars eject mass to form PNs. We present preliminary results from a programme of near–IR imaging, in which we study a sequence of objects, from extreme AGB stars through proto–planetaries to young, compact PNs. We aim to study the sequence of morphologies, to see where the onset of bipolar shaping occurs, and to use the IR molecular hydrogen lines to map neutral regions around ionized nebulae.

scholarly journals Atomic hydrogen in the planetary nebula IC 4997

1987 ◽  
Vol 122 ◽  
pp. 501-502
Author(s):  
C. Giovanardi ◽  
D.R. Altschuler ◽  
S.E. Schneider ◽  
P.R. Silverglate
Keyword(s):  
Atomic Hydrogen ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Expansion Velocity ◽  
Hydrogen Emission

In the course of a sensitive search for atomic hydrogen emission associated with planetary nebulae having high velocities relative to Galactic HI (Schneider et al. 1986), we detected absorption in the spectrum of IC 4997 (PK 58-10.1). This is only the second definite detection of HI associated with a PN. The velocity of the feature coincides precisely with that expected if the gas is expanding with the measured optical expansion velocity of 14 km s−1 (Sabbadin 1984), strongly suggesting an association.

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