Changes in the spectrum of Z Ursae Majoris during its rise through a maximum in 2014 June
2015 May 29
The semiregular variable Z UMa experienced a particularly deep minimum at the end of 2014 March, followed by a three-month rise to maximum. The rise and subsequent decline were followed with low resolution (R~1000) spectroscopy, possibly for the first time. The spectral type of Z UMa varied between M7III at minimum and M4III at maximum, while the bright hydrogen emission lines reported by observers during the last century now appear relatively weak and transitory.
(Login or click above to view the full paper including figures)