Publications Spring 2022

A further paper has been accepted for publication from RoCS - Rosseland Centre for Solar Physics. Postdoctoral Fellow Maryam Saberi presents her paper. 

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Postdoctoral Fellow Maryam Saberi has been with RoCS since early 2020. Photo: UiO

Title of the publication

First detection of AlF line emission towards M-type AGB stars

Publication:  arXiv e-prints

1st Author: Saberi, M

Position: Postdoctoral Fellow
Co-authors from RoCS:
  • Sven Wedemeyer

Short summary by the author:

The nucleosynthesis production of fluorine (F) is still a matter of debate. Asymptotic giant branch (AGB) stars are one of the main candidates for F production. However, their contribution to the total F budget is not fully known due to the lack of observations. In this paper, we report the detection of AlF line emission, one of the two main carriers of F in the gas-phase in the outflow of evolved stars, towards five nearby oxygen-rich AGB stars, o Ceti, R Leo, IK Tau, R Dor, and W Hya. From spatially resolved observations, we estimated the AlF emitting region with a radius ∼11R⋆ for o Ceti and ∼9R⋆ for R Leo. From population diagram analysis, we report the AlF column densities of ∼5.8×1015 cm−2 and ∼3×1015 cm−2 for o Ceti and R Leo, respectively, within these regions. For o Ceti, we used the C18O (v=0, J=3−2) observations to estimate the H2 column density of the emitting region. We found a fractional abundance of fAlF/H2∼(2.5±1.7)×10−8. This gives a lower limit on the F budget in o Ceti and is compatible with the solar F budget fF/H2=(5±2)×10−8. For R Leo, a fractional abundance fAlF/H2=(1.2±0.5)×10−8 is estimated. For other sources, we cannot precisely determine the emitting region based on the available data. Assuming an emitting region with a radius of ∼11R⋆ and the rotational temperatures derived for o Ceti and R Leo, we crudely approximated the AlF column density to be ∼(1.2−1.5)×1015 cm−2 in W Hya, ∼(2.5−3.0)×1014 cm−2 in R Dor, and ∼(0.6−1.0)×1016 cm−2 in IK Tau. These result in fractional abundances within a range of fAlF/H2∼(0.1−4)×10−8 in W Hya, R Dor, and IK Tau.

Read interview with Maryam Saberi

Published June 29, 2022 2:30 PM - Last modified June 29, 2022 2:33 PM