The Wind Acceleration Region of Betelgeuse: Resolved at Centimeter Wavelengths

Paper in proceeding, 2015

We present multi-epoch spatially resolved radio continuum observations of Betelgeuse (alpha Ori) at various combinations of wavelengths between 0.7 and 6.1 cm. We used the Very Large Array in the A configuration with the Pie Town antenna to spatially resolve its atmosphere at 0.7, 1.3, 2.0, and 6.1 cm at all epochs. Our findings are similar to those of Lim et al. (1998) in that Betelgeuse's opaque atmosphere extends from 2 to 612(star) between 0.7 and 6.1 cm with temperatures decreasing from similar to 3000 to 1800 K, respectively. We find no evidence of radio hotspots at any epochs even though we have sufficient spatial resolution and sensitivity at 0.7 and 1.3 cm to detect the hotspots recently reported with e-MERLIN at 5.2 cm.