scholarly journals High-resolution spectroscopy of SN 2017hcc and its blueshifted line profiles from post-shock dust formation

2020 ◽  
Vol 499 (3) ◽  
pp. 3544-3562
Author(s):  
Nathan Smith ◽  
Jennifer E Andrews
Keyword(s):  
High Resolution ◽  
Electron Scattering ◽  
Wavelength Dependence ◽  
High Resolution Spectroscopy ◽  
Shock Acceleration ◽  
Dust Formation ◽  
Line Profiles ◽  
Circumstellar Material ◽  
Post Shock ◽  
The Continuum

ABSTRACT SN 2017hcc was remarkable for being a nearby and strongly polarized superluminous Type IIn supernova (SN). We obtained high-resolution Echelle spectra that we combine with other spectra to investigate its line-profile evolution. All epochs reveal narrow P Cygni components from pre-shock circumstellar material (CSM), indicating an axisymmetric outflow from the progenitor of 40–50 km s−1. Broad and intermediate-width components exhibit the classic evolution seen in luminous SNe IIn: symmetric Lorentzian profiles from pre-shock CSM lines broadened by electron scattering at early times, transitioning at late times to multicomponent, irregular profiles coming from the SN ejecta and post-shock shell. As in many SNe IIn, profiles show a progressively increasing blueshift, with a clear flux deficit in red wings of the intermediate and broad velocity components after day 200. This blueshift develops after the continuum luminosity fades, and in the intermediate-width component, persists at late times even after the SN ejecta fade. In SN 2017hcc, the blueshift cannot be explained as occultation by the SN photosphere, pre-shock acceleration of CSM, or a lopsided explosion of CSM. Instead, the blueshift arises from dust formation in the post-shock shell and in the SN ejecta. The effect has a wavelength dependence characteristic of dust, exhibiting an extinction law consistent with large grains. Thus, SN 2017hcc experienced post-shock dust formation and had a mildly bipolar CSM shell, similar to SN 2010jl. Like other superluminous SNe IIn, the progenitor lost around 10 M⊙ due to extreme eruptive mass-loss in the decade before exploding.

High-resolution spectroscopy near the continuum limit: the microwave spectrum of trans-3-bromo-1,1,1,2,2-pentafluoropropane

2018 ◽  
Vol 117 (9-12) ◽  
pp. 1351-1359 ◽  
Author(s):  
Frank E. Marshall ◽  
Nicole Moon ◽  
Thomas D. Persinger ◽  
David J. Gillcrist ◽  
Nelson E. Shreve ◽  
...  
Keyword(s):  
High Resolution ◽  
Continuum Limit ◽  
Microwave Spectrum ◽  
High Resolution Spectroscopy ◽  
The Continuum

scholarly journals High resolution spectroscopy of RY Tauri: variability of the Na D line profiles

1990 ◽  
Vol 137 ◽  
pp. 219-220
Author(s):  
P.P. Petrov
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Young Stars ◽  
High Resolution Spectroscopy ◽  
Line Profiles

Ejection and accretion of gas clouds in the vicinity of RY Tau were discovered. The existense of large scale “stellar prominences” around young stars is suggested.

scholarly journals New Progress in Mode Detection and Identification in δ Scuti Stars by the Analysis of Line Profile Variations

2000 ◽  
Vol 176 ◽  
pp. 463-464
Author(s):  
L. Mantegazza ◽  
E. Poretti ◽  
M. Bossi ◽  
N. S. Nuñez ◽  
A. Sacchi ◽  
...  
Keyword(s):  
High Resolution ◽  
Line Profile ◽  
High Resolution Spectroscopy ◽  
Line Profiles ◽  
Powerful Technique ◽  
Mode Detection ◽  
Detection And Identification ◽  
Scuti Stars ◽  
Δ Scuti Stars ◽  
Nonradial Pulsation

Abstractδ Sct stars are among the most promising targets to perform ground-based asteroseismology. High resolution spectroscopy offers us a powerful technique to identify radial and nonradial pulsation modes, since we can easily detect oscillations and travelling features in the line profiles.

Problems in the Formation of Neutral Helium Lines in Early Type Stars

1970 ◽  
Vol 1 (7) ◽  
pp. 326-328
Author(s):  
R. W. Simpson
Keyword(s):  
Absorption Coefficient ◽  
Electron Scattering ◽  
Growth Analysis ◽  
Line Profiles ◽  
Early Type ◽  
Line Absorption ◽  
Early Type Stars ◽  
Made In ◽  
The Continuum

The aim of this work is to investigate certain assumptions that have been made in calculating line profiles and equivalent widths of neutral helium lines in early type stars. The effect of electron scattering on the continuum flux is investigated and a curve of growth analysis carried out to study this effect. The theories involved in calculating the line absorption coefficient are also investigated.

scholarly journals The peculiar star RX Puppis

1982 ◽  
Vol 70 ◽  
pp. 203-206
Author(s):  
M. Kafatos ◽  
A.G. Michalitsianos
Keyword(s):  
Accretion Disk ◽  
Line Emission ◽  
Wavelength Region ◽  
High Dispersion ◽  
Line Profiles ◽  
Peculiar Star ◽  
Dynamic Activity ◽  
Circumstellar Material ◽  
International Ultraviolet Explorer ◽  
The Continuum

AbstractWe have obtained the first high dispersion observations of RX Puppis in the wavelength region 1200 - 3200 A with the “International Ultraviolet Explorer” (IUE). The anomalies we observed in lines such as He II, C III], C IV, N III], N IV], 0 III], and Si III], that show split line profiles, Doppler displaced component(s) suggest dynamic activity in circumstellar material that probably has the form of rings and/or gas streamers between the cool giant and the hot companion, the Mg II lines show P-Cygni structure arising in the Mira primary. The continuum cannot be due to a star earlier than A0 II and it may arise in an accretion disk around the hot secondary. Moreover, the line emission requires photoionization either from a hot subdwarf or the inner accretion disk.

scholarly journals A Connection Between V/R and Polarization in Be Stars

2000 ◽  
Vol 175 ◽  
pp. 460-463 ◽  
Author(s):  
David McDavid ◽  
K.S. Bjorkman ◽  
J.E. Bjorkman ◽  
A.T. Okazaki
Keyword(s):  
Electron Scattering ◽  
Radiation Transfer ◽  
Density Wave ◽  
Circumstellar Disk ◽  
Be Stars ◽  
Line Profiles ◽  
Short Term ◽  
Density Perturbations ◽  
Density Pattern ◽  
The Continuum

AbstractOkazaki (1991) and Papaloizou, Savonije, & Henrichs (1992) suggested that the quasi-cyclic V/R variability observed in the emission line profiles of many Be stars is caused by a precessing one-armed density wave in the circumstellar disk. It seems likely that the changing aspect of such a non-axisymmetric density pattern might also lead to a related variation of the continuum polarization. We have searched for such an effect in two well-studied Be shell stars, ζ Tau and 48 Lib, based on data compiled from several groups of observers from 1984 to 1998. Using the Monte Carlo radiation transfer code of Wood, Bjorkman, Whitney, & Code (1996), we have calculated the polarization due to electron scattering in Be disks in the presence of one-armed density perturbations. Although the notorious long and short term deviations from strict periodicity present in Be stars make it difficult to rigorously demonstrate the connection between the V/R variability and the polarization variations, we have been able to find specific modes that are consistent with the observed V/R line profile variations together with the suspected polarization cycles.

scholarly journals High resolution spectroscopy of the hydrogen atom. II. Study of line profiles

1990 ◽  
Vol 51 (20) ◽  
pp. 2275-2292 ◽  
Author(s):  
J.C. Garreau ◽  
M. Allegrini ◽  
L. Julien ◽  
F. Biraben
Keyword(s):  
High Resolution ◽  
Hydrogen Atom ◽  
High Resolution Spectroscopy ◽  
Line Profiles

scholarly journals Spectroscopic diagnostics of dust formation and evolution in classical nova ejecta

2018 ◽  
Vol 619 ◽  
pp. A104 ◽  
Author(s):  
Steven N. Shore ◽  
N. Paul Kuin ◽  
Elena Mason ◽  
Ivan De Gennaro Aquino
Keyword(s):  
High Resolution ◽  
Dust Formation ◽  
Late Time ◽  
Line Profiles ◽  
Classical Novae ◽  
Spectroscopic Diagnostics ◽  
Classical Nova ◽  
Formation And Evolution ◽  
Compare And Contrast ◽  
General Method

A fraction of classical novae form dust during the early stages of their outbursts. The classical CO nova V5668 Sgr (Nova Sgr. 2015b) underwent a deep photometric minimum about 100 days after outburst that was covered across the spectrum. A similar event was observed for an earlier CO nova, V705 Cas (Nova Cas 1993) and a less optically significant event for the more recent CO nova V339 Del (Nova Del 2013). This study provides a “compare and contrast” of these events to better understand the very dynamical event of dust formation. We show the effect of dust formation on multiwavelength high resolution line profiles in the interval 1200 Å–9200 Å using a biconical ballistic structure that has been applied in our previous studies of the ejecta. We find that both V5668 Sgr and V339 Del can be modeled using a grey opacity for the dust, indicating fairly large grains (≳0.1 μ) and that the persistent asymmetries of the line profiles in late time spectra, up to 650 days after the event for V5668 Sgr and 866 days for V339 Del, point to the survival of the dust well into the transparent, nebular stage of the ejecta evolution. This is a general method for assessing the properties of dust forming novae well after the infrared is completely transparent in the ejecta.

scholarly journals Near-IR spectroscopic search for binary companions to dusty WC stars

2003 ◽  
Vol 212 ◽  
pp. 251-252 ◽  
Author(s):  
Watson P. Varricatt
Keyword(s):  
High Resolution ◽  
Emission Line ◽  
Binary Systems ◽  
Systematic Search ◽  
High Resolution Spectroscopy ◽  
Close Binary ◽  
Dust Formation ◽  
Near Ir ◽  
Ir Spectroscopic ◽  
Colliding Winds

Many late WC type Wolf-Rayet (WR) stars are known to form dust in their winds. While, in the case of episodic dust makers, it is now clear that dust formation takes place due to a colliding wind phenomenon, we still do not know for sure if binarity is the main reason for dust formation in persistent dust makers. This work is to understand, if persistent dust formation is also due to colliding winds in close binary systems. A systematic search for colliding winds is taken up via high resolution spectroscopy of the He i λ1.083μm emission line. Preliminary indications of binarity in many persistent dust makers are seen.

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