Episodes of Molecular Emission in the Optical Spectrum of IRAS 22272+5435

Emission of carbon-bearing molecular lines in multiple optical spectra of IRAS 22272+5435 from 2015 to 2017 is detected, and, for the first time in post–asymptotic giant branch stars, real-time evolution of these features is observed. Specifically, lines of various vibrational transitions of the CN...

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Main Authors: Kārlis Puķı̄tis, Laimons Začs, Julius Sperauskas
Format: Article
Language:English
Published: IOP Publishing 2023-01-01
Series:The Astrophysical Journal
Subjects:
Online Access:https://doi.org/10.3847/1538-4357/acc52b
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author Kārlis Puķı̄tis
Laimons Začs
Julius Sperauskas
author_facet Kārlis Puķı̄tis
Laimons Začs
Julius Sperauskas
author_sort Kārlis Puķı̄tis
collection DOAJ
description Emission of carbon-bearing molecular lines in multiple optical spectra of IRAS 22272+5435 from 2015 to 2017 is detected, and, for the first time in post–asymptotic giant branch stars, real-time evolution of these features is observed. Specifically, lines of various vibrational transitions of the CN Red system and C _2 Swan system are identified to be in emission. Contrary to the narrow and blueshifted AGB ejecta absorption lines, the emission profiles are broad and redshifted or blueshifted by no more than a few kilometers per second. Molecular emissions appear to be exclusive to spectra corresponding to pulsation phases closer to the star’s light maxima than minima, but there are also such spectra without emissions. The time required for emissions to reach the largest observed intensity or decrease to absorption is around 2–3 weeks. The C _2 Phillips system lines are observed to have emission components as well, but no evidence for their short-term variability is found. It is proposed that the observed emissions originate within few stellar radii above the photosphere.
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spelling doaj.art-217fe4508aef48b6ad23f010259e3f222023-09-03T11:29:58ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194817010.3847/1538-4357/acc52bEpisodes of Molecular Emission in the Optical Spectrum of IRAS 22272+5435Kārlis Puķı̄tis0https://orcid.org/0000-0003-2599-6126Laimons Začs1https://orcid.org/0000-0001-9301-3721Julius Sperauskas2https://orcid.org/0000-0003-0931-7744Laser Center, Faculty of Physics, Mathematics, and Optometry, University of Latvia , Raia bulvāris 19, LV-1586 Rı̄ga, Latvia ; karlis.pukitis@lu.lvLaser Center, Faculty of Physics, Mathematics, and Optometry, University of Latvia , Raia bulvāris 19, LV-1586 Rı̄ga, Latvia ; karlis.pukitis@lu.lvVilnius University Observatory , Saulëtekio al. 3, 10257 Vilnius, LithuaniaEmission of carbon-bearing molecular lines in multiple optical spectra of IRAS 22272+5435 from 2015 to 2017 is detected, and, for the first time in post–asymptotic giant branch stars, real-time evolution of these features is observed. Specifically, lines of various vibrational transitions of the CN Red system and C _2 Swan system are identified to be in emission. Contrary to the narrow and blueshifted AGB ejecta absorption lines, the emission profiles are broad and redshifted or blueshifted by no more than a few kilometers per second. Molecular emissions appear to be exclusive to spectra corresponding to pulsation phases closer to the star’s light maxima than minima, but there are also such spectra without emissions. The time required for emissions to reach the largest observed intensity or decrease to absorption is around 2–3 weeks. The C _2 Phillips system lines are observed to have emission components as well, but no evidence for their short-term variability is found. It is proposed that the observed emissions originate within few stellar radii above the photosphere.https://doi.org/10.3847/1538-4357/acc52bPost-asymptotic giant branch starsStellar atmospheresHigh resolution spectroscopyCircumstellar gasStellar windsShocks
spellingShingle Kārlis Puķı̄tis
Laimons Začs
Julius Sperauskas
Episodes of Molecular Emission in the Optical Spectrum of IRAS 22272+5435
The Astrophysical Journal
Post-asymptotic giant branch stars
Stellar atmospheres
High resolution spectroscopy
Circumstellar gas
Stellar winds
Shocks
title Episodes of Molecular Emission in the Optical Spectrum of IRAS 22272+5435
title_full Episodes of Molecular Emission in the Optical Spectrum of IRAS 22272+5435
title_fullStr Episodes of Molecular Emission in the Optical Spectrum of IRAS 22272+5435
title_full_unstemmed Episodes of Molecular Emission in the Optical Spectrum of IRAS 22272+5435
title_short Episodes of Molecular Emission in the Optical Spectrum of IRAS 22272+5435
title_sort episodes of molecular emission in the optical spectrum of iras 22272 5435
topic Post-asymptotic giant branch stars
Stellar atmospheres
High resolution spectroscopy
Circumstellar gas
Stellar winds
Shocks
url https://doi.org/10.3847/1538-4357/acc52b
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AT laimonszacs episodesofmolecularemissionintheopticalspectrumofiras222725435
AT juliussperauskas episodesofmolecularemissionintheopticalspectrumofiras222725435