Comparison of coronal hole and quiet-Sun chromosphere using IRIS Mg II h and k observations of polar off-limb regions

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00619110" target="_blank" >RIV/67985815:_____/25:00619110 - isvavai.cz</a>

Result on the web

<a href="https://hdl.handle.net/11104/0365941" target="_blank" >https://hdl.handle.net/11104/0365941</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/1538-4357/adbc69" target="_blank" >10.3847/1538-4357/adbc69</a>

Result language

angličtina

Original language name

Comparison of coronal hole and quiet-Sun chromosphere using IRIS Mg II h and k observations of polar off-limb regions

Original language description

Solar quiet regions are divided into coronal hole regions (CH) and quiet-Sun regions (QS). The global magnetic field in CH is considered open to interplanetary space, while that in QS is closed. To constrain the solar atmosphere and solar wind model, we statistically compared CH and QS in the chromosphere by quantitatively analyzing all available high-resolution spectral data sets of polar off-limb regions taken from the entire catalog of the Interface Region Imaging Spectrograph (IRIS) satellite. We extracted the characteristic quantities from the Mg ii h and k line profiles and compared the dependence of those quantities on the height from the photospheric limb. The main findings are as follows. First, the integrated intensities in the Mg ii k line show a steeper decrease with height in QS while they remain bright at higher altitudes in CH. Second, the unsigned line-of-sight velocities in the Mg ii k line generally increase with height in both regions, although the unsigned velocities increase with height more strongly in QS than in CH. Third, the Mg ii k line widths increase just above the limb and then decrease with height in both CH and QS, but are overall larger for CH than for QS, especially at the lower altitudes. Finally, we found the ratio of the Mg ii k and h lines to show a two-step increase with height in both regions. The results suggest the spicules are higher in CH, and the CH chromosphere exhibits faster motions than the QS.

Czech name

—

Czech description

—

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

<a href="/en/project/GA25-18282S" target="_blank" >GA25-18282S: ESA space coronagraphy with Czech participation</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

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

983

Issue of the periodical within the volume

2

Country of publishing house

GB - UNITED KINGDOM

Number of pages

17

Pages from-to

108

UT code for WoS article

001464716000001

EID of the result in the Scopus database

2-s2.0-105003045840