Pavlenko, Yakiv V;
Tennyson, Jonathan;
Yurchenko, Sergei N;
Schmidt, Mirek R;
Jones, Hugh RA;
Lyubchik, Yuri;
Mascareño, A Suárez;
(2022)
AlH lines in the blue spectrum of Proxima Centauri.
Monthly Notices of the Royal Astronomical Society
, Article stac2588. 10.1093/mnras/stac2588.
(In press).
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Abstract
The recently-computed ExoMol line lists for isotopologues of AlH are used to analyse the blue spectrum (4000-4500 Å) of Proxima Cen (M5.5 V). Comparison of the observed and computed spectra enables the identification of a large number of 27AlH lines of the A 1Π –X 1Σ+ band system: the spectral range covering 1-0, 0-0 and 1-1 bands is dominated by clearly resolved AlH lines. We reveal the diffuse nature of transitions close to the dissociation limit which appears in the form of increasingly wider (up to 5 Å) and shallower (up to the continuum confusion limit) AlH line profiles. The predicted wavelengths of AlH diffuse lines are systematically displaced. The effect of broadening by predissociation states on the line profiles is included by increasing the radiative damping rate by up to 5 orders of magnitude. We determine empirical values of damping rates for a number of the clean 0-0 Q-branch transitions by comparing the observed and synthetic stellar spectra. We find excellent agreement between our damping rates and lifetimes available in the literature. A comparison of 27Al1H ExoMol and REALH spectra shows that the observed spectrum is better described by the ExoMol line list. A search for 26Al1H lines in the Proxima Cen spectrum does not reveal any notable features; giving an upper limit of 27Al1H /26Al1H >100.
| Type: | Article |
|---|---|
| Title: | AlH lines in the blue spectrum of Proxima Centauri |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stac2588 |
| Publisher version: | https://doi.org/10.1093/mnras/stac2588 |
| Language: | English |
| Additional information: | © The Author(s) 2022. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | Line: identification, molecular data, opacity, stars: atmospheres, stars: late-type, stars: individual: Proxima Cen |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10156109 |
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