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arXiv · 1604.04635

EG Andromedae: A New Orbit and Additional Evidence for a Photoionized Wind

Scott J. Kenyon·Michael R. Garcia
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Abstract

We analyze a roughly 20 yr set of spectroscopic observations for the symbiotic binary EG And. Radial velocities derived from echelle spectra are best-fit with a circular orbit having orbital period P = 483.3 +- 1.6 days and semi-amplitude K = 7.34 +- 0.07 km/sec. Combined with previous data, these observations rule out an elliptical orbit at the 10-sigma level. Equivalent widths of H~I Balmer emission lines and various absorption features vary in phase with the orbital period. Relative to the radius of the red giant primary, the apparent size of the H II region is consistent with a model where a hot secondary star with effective temperature of roughly 75,000 K ionizes the wind from the red giant.

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Scott J. Kenyon, Michael R. Garcia. 2016-04-15. EG Andromedae: A New Orbit and Additional Evidence for a Photoionized Wind. https://doi.org/10.3847/0004-6256%2F152%2F1%2F1

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