Analysis of the Optical Emission Lines of SN 1987A

1990 ◽  
Vol 99 ◽  
pp. 664 ◽  
Author(s):  
J. A. de Freitas Pacheco
Keyword(s):  
Optical Emission ◽  
Emission Lines ◽  
Sn 1987A

scholarly journals Dust Condensation in the Ejecta of SN 1987A

1989 ◽  
Vol 120 ◽  
pp. 164-179 ◽  
Author(s):  
L.B. Lucy ◽  
I.J. Danziger ◽  
C. Gouiffes ◽  
P. Bouchet
Keyword(s):  
Quantitative Analysis ◽  
Light Curve ◽  
Amorphous Carbon ◽  
Interstellar Dust ◽  
Thermal Emission ◽  
Optical Emission ◽  
Emission Lines ◽  
Carbon Particles ◽  
Sn 1987A ◽  
Dust Condensation

AbstractAn asymmetry of optical emission lines that appeared in Sept. 1988 is interpreted as evidence of dust condensation within the metal-rich ejecta of SN 1987A. A quantitative analysis of this spectroscopic effect is given and shown to be compatible with the photometric record. Moreover, observational and theoretical estimates of the bolometric light curve come into agreement when the far-IR excess is interpreted as thermal emission by grains in the ejecta. A grain population comprising small silicate grains with an admixture of graphite or amorphous carbon particles is suggested by the data. The relevance of this discovery to suggestions that supernovae are major sources of interstellar dust is briefly discussed.

scholarly journals Effects of the soft X-ray burst from SN 1987A on its circumstellar medium

1989 ◽  
Vol 8 ◽  
pp. 223-228
Author(s):  
Peter Lundqvist ◽  
Claes Fransson
Keyword(s):  
Optical Emission ◽  
Emission Lines ◽  
X Ray ◽  
Physical Conditions ◽  
Sn 1987A ◽  
Circumstellar Medium

AbstractThe observations of the narrow UV and optical emission lines from SN 1987A are modelled as reprocessed radiation in a shell around the supernova, heated and ionized by the soft X-ray and EUV radiation at the shock breakout. Constraints on the early soft X-ray burst are discussed, as well as the physical conditions and abundances in the shell.

scholarly journals Molecular gas around the Wolf-Rayet star WR 18 (WN4)

2003 ◽  
Vol 212 ◽  
pp. 732-733
Author(s):  
Anthony P. Marston
Keyword(s):  
Mass Loss ◽  
Optical Emission ◽  
Emission Lines ◽  
Molecular Gas ◽  
Evolved Stars ◽  
Ring Nebula ◽  
History Of ◽  
Optical Ring ◽  
Ring Nebulae ◽  
Rayet Star

Optically observed ring nebulae and H i cavities around Wolf-Rayet stars have enabled us to obtain information on the history of mass-loss associated with these massive evolved stars. However, such studies have left a number of unanswered questions regarding the amount of mass-loss and the conditions of the stars during a sequence of mass-loss phases. Here we discuss the molecular gas environments of the WR star WR 18, which has an associated optical ring nebula NGC 3199. Our observations show that significant amounts of molecular gas appear close to and associated with the star. Mapping of molecular CO near the star shows that molecular materials appear to substantially avoid areas of optical emission and, instead, form a distorted clumpy shell interior to NGC 3199. Molecular emission lines are broader than lines seen in the interstellar medium and suggest the shell is composed of ejecta. This is further corroborated by the enhanced abundances of molecules containing C, N and O. Implications of the observations for the evolution of WR 18 are discussed.

scholarly journals Filtered CCD images of southern Herbig-Haro objects

1987 ◽  
Vol 122 ◽  
pp. 189-190
Author(s):  
B. Whitmore ◽  
D.H.M. Cameron ◽  
R.F. Warren-Smith
Keyword(s):  
High Velocity ◽  
Optical Emission ◽  
Emission Lines ◽  
Ccd Cameras ◽  
Hh Objects

It is currently believed that Herbig-Haro (HH) objects are a consequence of a high-velocity (up to at least 200 km s−1) outflow of material from a young embedded star. These flows can often be detected by deep observations of optical emission lines using CCD cameras.

scholarly journals Colliding Stellar Winds in O-type Close Binary Systems

1992 ◽  
Vol 135 ◽  
pp. 146-148
Author(s):  
D.R. Gies ◽  
M.S. Wiggs
Keyword(s):  
Binary Systems ◽  
Optical Emission ◽  
Emission Lines ◽  
Optical Observations ◽  
Close Binary ◽  
High Dispersion ◽  
Stellar Winds ◽  
Close Binary Systems ◽  
Circumstellar Gas ◽  
The Individual

In close binary systems of O-type stars, the individual stellar winds will collide between the stars to form shock fronts (Stevens et al. 1992). Binaries with equally luminous stars will have winds of comparable strength, and the shock will occur near the mid-plane between the stars, but in binaries of unequal luminosity, the interaction will occur along a bow shock wrapped around the star with the weaker wind. The presence of the shock region can be detected through excess X-ray emission (Chlebowski & Garmany 1990), and orbital phase-related variations in the UV P Cygni lines (Shore & Brown 1988) and optical emission lines (formed in high density regions of circumstellar gas).We have begun a search for colliding winds through a study of the optical emission lines and UV P Cygni lines in four massive binaries, AO Cas (Gies & Wiggs 1991), Plaskett’s star = HD 47129 (Wiggs & Gies 1992), 29 UW CMa and ι Ori. The optical observations consist of high S/N spectra of the Hα and He I λ6678 region obtained with the University of Texas McDonald Observatory 2.1-m telescope and coudé Reticon system. The UV observations were culled from archival IUE high dispersion spectra of several P Cygni features (N V λ1240, Si IV λ1400, C IV λ1550).

scholarly journals Discovery of diffuse optical emission lines from the inner Galaxy: Evidence for LI(N)ER-like gas

2020 ◽  
Vol 6 (27) ◽  
pp. eaay9711 ◽  
Author(s):  
D. Krishnarao ◽  
R. A. Benjamin ◽  
L. M. Haffner
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Center ◽  
Line Emission ◽  
Galactic Nuclei ◽  
Optical Emission ◽  
Hydrogen Gas ◽  
Emission Lines ◽  
Neutral Gas ◽  
Optical Line ◽  
Tilted Disk

Optical emission lines are used to categorize galaxies into three groups according to their dominant central radiation source: active galactic nuclei, star formation, or low-ionization (nuclear) emission regions [LI(N)ERs] that may trace ionizing radiation from older stellar populations. Using the Wisconsin H-Alpha Mapper, we detect optical line emission in low-extinction windows within eight degrees of Galactic Center. The emission is associated with the 1.5-kiloparsec-radius “Tilted Disk” of neutral gas. We modify a model of this disk and find that the hydrogen gas observed is at least 48% ionized. The ratio [NII] λ6584 angstroms/Hα λ6563 angstroms increases from 0.3 to 2.5 with Galactocentric radius; [OIII] λ5007 angstroms and Hβ λ4861 angstroms are also sometimes detected. The line ratios for most Tilted Disk sightlines are characteristic of LI(N)ER galaxies.

scholarly journals High resolution observations of BD +30 3639 − A young PN

1997 ◽  
Vol 180 ◽  
pp. 99-99
Author(s):  
M. Bryce ◽  
G. Mellema
Keyword(s):  
Hubble Space Telescope ◽  
Optical Emission ◽  
Closed Shell ◽  
Detailed Comparison ◽  
Central Star ◽  
Emission Lines ◽  
Radio Image ◽  
Spatially Resolved ◽  
True Shape ◽  
Spatially Extended

Sub-arcsecond resolution radio and optical images of the young planetary nebula BD +30 3639 look superficially very similar, showing a pronounced box-shaped bright nebular shell. However, a detailed comparison at high spatial resolution reveals several regions where the optical emission is obscured by localised dusty regions. The highest resolution radio image to date of this PN, a 6 cm map obtained by combining MERLIN and VLA observations (Bryce et al, 1996) has been compared to the highest resolution optical Hβ image from the Hubble Space Telescope (obtained by J.P. Harrington and collaborators) to reveal the differences in emission which are probably due in the main to dust obscuration at optical wavelengths (Bryce et al, 1996 & Arnaud, Borkowski & Harrington, 1996). New 6 km s–1 resolution, spatially resolved spectra of optical emission lines, obtained using the Utrecht echelle spectrometer on the 4.2 m William Herschell Telescope, show that this nebula is bright in the low ionisation emission lines of [N II] 6548 + 6584 å and also appears to be more spatially extended than in the fainter, high ionisation [O III] 5007 å emission. The velocity ellipse observed from a long slit oriented north-south was found to be tilted, indicating an inclined, elliptical morphology rather than a simple, radially expanding spherical shell and the gaps in the velocity ellipse observed with an east-west slit suggest that the true shape is probably an open ring-like structure rather than a closed shell. A deep exposure of the [N II] 6584 å emission line appears to show a collimated, accelerating flow in an eastward direction away from the central star and extending well beyond the main bright nebular ring. It was also observed in the Hydrogen and [Nii] 6548 å emission lines. The H2 1–0 S(1) image of BD +30 3639 by Graham et al (1993) also shows a feature to the east of the main nebular ring. This may well be related to faint halo structures detected by Harrington and collaborators from their HST images (private communication).

scholarly journals Studies of the large Magellanic Cloud using optical interstellar emission lines

1991 ◽  
Vol 148 ◽  
pp. 421-427
Author(s):  
J. Meaburn
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Emission Lines ◽  
Optical Observations ◽  
Sn 1987A ◽  
30 Doradus

Optical observations have been made of the halo of 30 Doradus, in the vicinity of SN 1987A and of giant shells in the LMC.

scholarly journals Understanding the Nebular Spectrum of SN 1987A

1996 ◽  
Vol 145 ◽  
pp. 223-234
Author(s):  
Richard McCray
Keyword(s):  
Emission Line ◽  
Infrared Emission ◽  
Emission Lines ◽  
Low Density ◽  
Simple Method ◽  
Sn 1987A ◽  
Hydrogen Recombination ◽  
Inner Envelope

The nebular spectra of supernovae differ from those of better-known emission nebulae in that many of the emission lines are optically thick. Here we sketch the theory for interpreting such spectra, and show how it can be used to interpret prominent emission line systems in the spectrum of SN 1987A. As examples, we describe: (1) a simple method to infer the density of OI from observations of the evolution of the doublet ratio in [O I]λλ6300; (2) new kind of hydrogen recombination hne spectrum; (3) an analysis showing that the Call infrared emission lines must come from primordial, not newly-synthesized, calcium; (4) a theory for the Fe/Co/Ni emission lines that shows that the inner envelope of SN 1987A must have a foamy texture, in which low density radioactive bubbles of Fe/Co/Ni reside in a massive substrate of hydrogen, helium, and other elements.

Sign in / Sign up

Export Citation Format

Share Document