Dark Off-limb Gap: Manifestation of a Temperature Minimum and the Dynamic Nature of the Chromosphere

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F22%3A00562599" target="_blank" >RIV/67985815:_____/22:00562599 - isvavai.cz</a>

Result on the web

<a href="https://hdl.handle.net/11104/0335141" target="_blank" >https://hdl.handle.net/11104/0335141</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/1538-4357/ac8d8e" target="_blank" >10.3847/1538-4357/ac8d8e</a>

Result language

angličtina

Original language name

Dark Off-limb Gap: Manifestation of a Temperature Minimum and the Dynamic Nature of the Chromosphere

Original language description

We study off-limb emission of the lower solar atmosphere using high-resolution imaging spectroscopy in the H beta and Ca ii 8542 angstrom lines obtained with the CHROMospheric Imaging Spectrometer (CHROMIS) and the CRisp Imaging SpectroPolarimeter (CRISP) on the Swedish 1 m Solar Telescope. The H beta line-wing images show the dark intensity gap between the photospheric limb and chromosphere, which is absent in the Ca ii images. We calculate synthetic spectra of the off-limb emissions with the RH code in one-dimensional spherical geometry and find good agreement with the observations. The analysis of synthetic line profiles shows that the gap in the H beta line-wing images maps the temperature minimum region between the photosphere and chromosphere due to the well-known opacity and emissivity gap of Balmer lines in this layer. However, the observed gap is detected farther from the line core in the outer line-wing positions than in the synthetic profiles. We found that an increased microturbulence in the model chromosphere is needed to reproduce the dark gap in the outer line wing, suggesting that the observed H beta gap is the manifestation of the temperature minimum and the dynamic nature of the solar chromosphere. The temperature minimum produces a small enhancement in synthetic Ca ii line-wing intensities. Observed off-limb Ca ii line-wing emissions show similar enhancement below the temperature minimum layer near the edge of the photospheric limb.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astrophysical Journal

ISSN

0004-637X

e-ISSN

1538-4357

Volume of the periodical

937

Issue of the periodical within the volume

2

Country of publishing house

GB - UNITED KINGDOM

Number of pages

11

Pages from-to

56

UT code for WoS article

000861000000001

EID of the result in the Scopus database

2-s2.0-85139752752