Changes in the spectrum of Z Ursae Majoris during its rise through a maximum in June 2014

TL;DR

This study documents the spectral changes of Z Ursae Majoris during its rise to maximum brightness in June 2014, revealing variations in spectral type and emission lines through low-resolution spectroscopy.

Contribution

First low-resolution spectroscopic analysis of Z UMa during its rise to maximum, detailing spectral type variations and emission line behavior.

Findings

Spectral type varied from M7III to M4III during the rise.

Hydrogen emission lines appeared weak and transient.

Spectral changes correlated with brightness variations.

Abstract

The semiregular variable Z UMa experienced a particularly deep minimum at the end of March 2014 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.