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Radio spectral index analysis of southern hemisphere symbiotic stars

Citation

Dickey, JM and Weston, JHS and Sokoloski, JL and Vrtilek, SD and McCollough, M, Radio spectral index analysis of southern hemisphere symbiotic stars, Astrophysical Journal, 911, (1) pp. 1-10. ISSN 0004-637X (2021) [Refereed Article]

Copyright Statement

2021. The American Astronomical Society. All rights reserved.

DOI: doi:10.3847/1538-4357/abe774

Abstract

Symbiotic stars show emission across the electromagnetic spectrum from a wide array of physical processes. At centimeter waves, both synchrotron and thermal emissions are seen, often highly variable and associated with outbursts in the optical and X-rays. Most models of the radio emission include an ionized region within the dense wind of the red giant star that is kept ionized by activity on the white dwarf companion or its accretion disk. In some cases, there is ongoing shell burning on the white dwarf due to its high mass accretion rate or a prior nova eruption; in other cases, nuclear fusion occurs only occasionally as recurrent nova events. In this study, we measure the spectral indices of a sample of symbiotic systems in the Southern Hemisphere using the Australia Telescope Compact Array. Putting our data together with results from other surveys, we derive the optical depths and brightness temperatures of some well-known symbiotic stars. Using parallax distances from Gaia Data Release 3, we determine the sizes and characteristic electron densities in the radio emission regions. The results show a range of a factor of 10(4) in radio luminosity and a factor of 100 in linear size. These numbers are consistent with a picture where the rate of shell burning on the white dwarf determines the radio luminosity. Therefore, our findings also suggest that radio luminosity can be used to determine whether a symbiotic star is powered by accretion alone or also by shell burning.

Item Details

Item Type:Refereed Article
Keywords:Symbiotic binary stars, stellar accretion disks, white dwarf stars, interacting binary stars
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in engineering
UTAS Author:Dickey, JM (Professor John Dickey)
ID Code:152795
Year Published:2021
Web of Science® Times Cited:1
Deposited By:Mathematics
Deposited On:2022-08-24
Last Modified:2022-09-19
Downloads:0

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