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

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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

Název v anglickém jazyce

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

Popis výsledku anglicky

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

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

—

Rok uplatnění

2019

Kód důvěrnosti údajů

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

Název periodika

Astronomy & Astrophysics

ISSN

1432-0746

e-ISSN

—

Svazek periodika

623

Číslo periodika v rámci svazku

February

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

7

Strana od-do

L1

Kód UT WoS článku

000459847800001

EID výsledku v databázi Scopus

2-s2.0-85062782472