scholarly journals Infrared Images and Line Profiles of Planetary Nebulae

1989 ◽  
Vol 131 ◽  
pp. 178-178
Author(s):  
M. G. Smith ◽  
T. R. Geballe ◽  
C. Aspin ◽  
I. S. Mclean ◽  
P. F. Roche

We present high spatial resolution infrared images of the planetary nebulae NGC 7027, M2-9, BD +30 3639, NGC 7099 and NGC 7662. These were taken through a selection of broad and narrow-band line and continuum filters (including a Fabry-Pérot interferometer) using the 2D infrared array “IRCAM” on the United Kingdom Infrared Telescope, UKIRT, in July 1987. Comparison is made with recently published high-resolution VLA radio maps (Basart and Daub 1987, Ap. J., 317, 412) and mid-IR Wyoming Infrared Telescope raster-scanning maps (Bentley et al.1984, Ap. J., 278, 665).

1989 ◽  
pp. 178-178
Author(s):  
M. G. Smith ◽  
T. R. Geballe ◽  
C. Aspin ◽  
I. S. McLean ◽  
P. F. Roche

1993 ◽  
Vol 155 ◽  
pp. 378-378
Author(s):  
K.C. Sahu ◽  
J.R. Walsh ◽  
N.A. Walton ◽  
S.R. Pottasch

TAURUS, the imaging Fabry-Perot spectrometer, using a CCD detector, has been commissioned on the 4.2m William Herschel Telescope, creating a powerful tool for studying the kinematics of emission line objects such as planetary nebulae. The mode of operation when using a CCD is different to that with IPCS (where rapid scanning is employed), so that account has to be taken of changes in atmospheric transmission between CCD readouts. The large dynamic range of the CCD (>200) allows the simultaneous study of the line profiles from the right and faint parts of the nebulae.


2003 ◽  
Vol 209 ◽  
pp. 376-376
Author(s):  
J. Bernard Salas ◽  
S. R. Pottasch ◽  
P. R. Wesselius ◽  
P. Marigo

Accurate chemical abundances for the following planetary nebulae (PNe); NGC 6537, He 2-111, NGC 6302, NGC 6445, NGC 6741, NGC 7027, NGC 7662, NGC 2440 and NGC 5315 have been derived using data from the Infrared Space Observatory (ISO) and the International Ultraviolet Explorer (IUE). Optical data from the literature has also been used. These work has been published by Pottasch et al. (2001), Bernard Salas et al. (2001 and 2002). In particular, the use of the ISO data has reduced the need for ionization correction factors. Furthermore, infrared data avoid or reduce many problems when deriving these abundances, namely: temperature fluctuations in the nebula, and extinction corrections. The electron temperature (Te) and density of the PNe has been derived. For those PNe in which the Te has been derived for several ions a trend with the ionization potential is present. Ions with high stages of ionization give higher Te, probably because they are formed close to the central star. The chemical abundances measured in these PNe give some hint of the nucleosynthesis and mixing processes experienced by their progenitor stars. In this view, a preliminary comparison with synthetic TP-AGB models is made (Bernard Salas et al. (in prep.)). NGC 7027, NGC 6741, NGC 2440, and NGC 6445 are consistent with the occurrence of the 3rd dredge-up due to both C12 and He4 enrichment. NGC 6537, NGC 6302, and He 2-111 are likely to have stellar progenitors experiencing hot bottom burning due to the low C12 and high N14 abundances.


1993 ◽  
Vol 155 ◽  
pp. 335-335
Author(s):  
B.J. Hrivnak ◽  
S. Kwok ◽  
T.R. Geballe

Sixteen candidates for proto-planetary nebulae have been observed with low-resolution infrared spectroscopy in the H and K bands, and 6 in the L band, using the United Kingdom Infrared Telescope. In the H band, the objects show hydrogen Brackett lines in absorption. In the K band, absorption bands (del v=2) of CO were observed, and in three cases the CO bands are in emission. The CO spectrum of IRAS 22272+5435 was found to change from emission to absorption over a three-month interval. This CO emission can be interpreted as an indication of some recent episodes of mass loss in these objects. Four of the objects were found to possess an emission feature at 3.3 um, usually associated with PAHs, and two of these show an unusually strong 3.4 um emission feature (Geballe, Tielens, Kwok, & Hrivnak 1992, ApJ, 387, L89).


1994 ◽  
Vol 154 ◽  
pp. 379-392
Author(s):  
D. Deming ◽  
T. Hewagama ◽  
D. E. Jennings ◽  
G. McCabe ◽  
G. Wiedemann

Recent polarimetric observations of the 12.32-μm emission line have provided the observational basis for deriving vector magnetic fields in the upper photosphere with great sensitivity. We use a line source function from the non-LTE model of Carlsson, Rutten and Shchukina, and calculate the radiative transfer of the Stokes I, Q, U, and V profiles. The results show that the profiles are not significantly affected by magneto-optical effects or by saturation, and reliable vector fields can be extracted by simply fitting the Seares relations to the Stokes profiles. Vector field observations for sunspots have shown that the field extends well beyond the photometric boundary of the sunspot, but that the field strength at the penumbral/photospheric boundary is less than half of the sunspot-center value. Within a mature sunspot, the 12-μm line profiles contain essentially no unpolarized radiation, indicating that the field is not intermittent in the sense of containing discrete flux tubes separated by field-free regions. We describe the design of a 12-μm Stokes polarimeter incorporating a high-resolution Fabry-Perot etalon and a 128 × 128 infrared array detector.


1989 ◽  
Vol 131 ◽  
pp. 189-189
Author(s):  
D.P.K. Banerjee ◽  
B. G. Anandarao

The Planetary Nebulae IC 4593 and NGC 6153 are two rather compact objects not well studied. The nebula IC 4593 is about 12 arcsec in diameter and has a central star of Type 07 f; while the southern nebula NGC 6153 is about 22 arcsec in diameter and its central star is faint and of unknown spectral type. Using a high-resolution scanning Fabry-Pérot spectrometer we have made profile measurements of emission lines Hα λ6563 A, [O III] λ5007 A, and [N II] λ6584 A in the central regions of these two nebulae. We have found expansion velocities for IC 4593 of 40 km s−1 in [N II] and 16 km s−1 in [O III]. In the case of NGC 6153, we have obtained expansion velocities of 15 km s−1 in [N II] and 13 km s−1 in [O III] line. The profiles in Hα in both the nebulae dis not show a double peaked feature due to the larger thermal broadening. In the case of IC 4593, both [O III] and [N II] profiles showed complex structures. These results and their interpretation will be discussed.


1989 ◽  
Vol 131 ◽  
pp. 212-212
Author(s):  
M. Peimbert ◽  
S. Torres-Peimbert

From the study of the λλ5876, 7065 and 10830 He I line intensities in NGC 6572, NGC 6803, NGC 7009, NGC 7027, NGC 7662 and IC 418, it is found that the I(10830)/I(5876) ratio is weaker than expected. By considering estimates of the optical depth at λ10830 due to dust absorption and by determining the optical depth at λ10830 due to atomic absorption, it is argued that dust absorption of λ(10830) photons is not the cause for the low I(10830)/I(5876) ratios. By assuming that the 23S He0 state is depopulated only by radiative transitions to the 11S state and by triplet-singlet exchange collisions, it is found that its population is about a factor of two smaller than expected. This result is in agreement with a previous study of the λ3889, 4472, 5876, 6678 and 7065 line intensities in a group of thirteen Type I planetary nebulae. One of the main implications of the underpopulation of the 23S level is that the collisional effects in the N(He)/N(H) abundance ratios of planetary nebulae and 0-poor extragalactic H II regions are smaller than previously thought.


This collection examines the phenomenon of the operatic canon: its formation, history, current ontology and practical influence, and future. It does so by taking an international and interdisciplinary view: the workshops from which it was derived included the participation of critics, producers, artistic directors, stage directors, opera company CEOs, and even economists, from the United Kingdom, the United States, France, Italy, Ireland, Germany, the Netherlands, Denmark, and Canada. The volume is structured as a series of dialogues: each subtopic is addressed by two essays, introduced jointly by the authors, and followed by a jointly compiled list of further reading. These paired essays complement each other in different ways, for example by treating the same geographical location in different periods, by providing different national or regional perspectives on the same period, or by thinking through similar conceptual issues in contrasting milieus. Part I consists of a selection of surveys of operatic production and consumption contexts in France, Italy, Germany, England, Russia, and the Americas, arranged in rough order from the late seventeenth century to the late nineteenth century. Part II is a (necessarily) limited sample of subjects that illuminate the operatic canon from different—sometimes intentionally oblique—angles, ranging from the influence of singers to the contiguous genres of operetta and musical theater, and the effects of recording and broadcast over almost 150 years. The volume concludes with two essays written by prominent figures from the opera industry who give their sense of the operatic canon’s evolution and prospects.


2003 ◽  
Vol 589 (1) ◽  
pp. 439-443 ◽  
Author(s):  
Holly L. Maness ◽  
Saeqa D. Vrtilek ◽  
Joel H. Kastner ◽  
Noam Soker

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