A Sensitive Test for Far Ultraviolet CO absorption in the Outflow of our Nearest Supernova Progenitor - Antares
Abstract
The massive red supergiant Antares (alpha Sco A: M1 Iab) is an excellent star to test theoretical models of mass loss because its distance, age, stellar parameters, mass-loss rate, and interstellar reddening are well established. The early-M supergiants pose a particular challenge for models of mass loss driven by radiation pressure on molecules and/or dust: The circumstellar molecular abundances and dust-to-gas mass ratios are lower than for later-M spectral-types, but they still manage to drive massive winds.
We request deep FUV and NUV observations to perform an extremely sensitive test for the most robust circumstellar molecule, CO, by observing its Fourth-Positive electronic bands against the FUV continuum of the M supergiant Antares. These observations will enable us measure any CO present in the outflow, and to place upper-limits on the effective radiation acceleration it can provide. The proposed observations will also provide an invaluable dataset for Antares, the oft neglected southern twin of Betelgeuse, and our nearest Type II supernova progenitor.- Publication:
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HST Proposal
- Pub Date:
- May 2020
- Bibcode:
- 2020hst..prop16256H