Spectroscopic and Photometric Variability in the A0 Supergiant HR 1040

David J. Corliss (1,2), Nancy D. Morrison (2), and Saul J. Adelman (3)

1 - The University of Toledo; 2 - Wayne State University; 3 - The Citadel

A time-series analysis of spectroscopic and photometric observables of the A0 Ia supergiant HR 1040 has been performed, including equivalent widths, radial velocities, and Strömgren photometric indices. The data, obtained from 1993 through 2007, include 152 spectroscopic observations from the Ritter Observatory 1 m telescope and 269 Strömgren photometric observations from the Four College Automated Photoelectric Telescope. Typical of late B- and early A-type supergiants, HR 1040 has a highly variable Hα profile. The star was found to have an intermittent active phase marked by correlation between the Hα absorption equivalent width and blue-edge radial velocity and by photospheric connections observed in correlations to equivalent width, second moment and radial velocity in Si II λλ6347, 6371. High-velocity absorption (HVA) events were observed only during this active phase. HVA events in the wind were preceded by photospheric activity, including Si II radial velocity oscillations 19–42 days prior to onset of an HVA event and correlated increases in Si II Wλ and second moment from 13 to 23 days before the start of the HVA event. While increases in various line equivalent widths in the wind prior to HVA events have been reported in the past in other stars, our finding of precursors in enhanced radial velocity variations in the wind and at the photosphere is a new result.

Reference: AJ, 150, 190
Status: Manuscript has been accepted

Weblink: http://iopscience.iop.org/article/10.1088/0004-6256/150/6/190


Email: nancy.morrison@utoledo.edu