Detection of highly excited OH towards AGB stars A new probe of shocked gas in the extended atmospheres

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F19%3A00539804" target="_blank" >RIV/67985815:_____/19:00539804 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1051/0004-6361/201935049" target="_blank" >https://doi.org/10.1051/0004-6361/201935049</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/201935049" target="_blank" >10.1051/0004-6361/201935049</a>

Result language

angličtina

Original language name

Detection of highly excited OH towards AGB stars A new probe of shocked gas in the extended atmospheres

Original language description

We characterise the gas in the extended atmospheres of the oxygen-rich asymptotic giant branch (AGB) stars W Hya and R Dor using high angular resolution ALMA observations. We analyse the molecular excitation using a population diagram and find rotational temperatures of similar to 2500 K and column densities of similar to 10(19) cm(-2) for both sources. For W Hya, we observe emission from vibrationally excited H2O arising from the same region as the OH emission. Moreover, CO v = 1, J = 3 - 2 emission also shows a brightness peak in the same region. Considering optically thin emission and the rotational temperature derived for OH, we find a CO column density similar to 15 times higher than that of OH, within an area of (92 x 84) mas(2) centred on the OH emission peak. These results should be considered tentative because of the simple methods employed. The observed OH line frequencies differ significantly from the predicted transition frequencies in the literature, and provide the possibility of using OH lines observed in AGB stars to improve the accuracy of the Hamiltonian used for the OH molecule. We predict stronger OH Lambda-doubling lines at millimetre wavelengths than those we detected. These lines will be a good probe of shocked gas in the extended atmosphere and are possibly even suitable as probes of the magnetic field in the atmospheres of close-by AGB stars through the Zeeman effect.n

Czech name

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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

—

Publication year

2019

Confidentiality

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

Name of the periodical

Astronomy & Astrophysics

ISSN

1432-0746

e-ISSN

—

Volume of the periodical

623

Issue of the periodical within the volume

February

Country of publishing house

FR - FRANCE

Number of pages

7

Pages from-to

L1

UT code for WoS article

000459847800001

EID of the result in the Scopus database

2-s2.0-85062782472