Identification of SrF molecular lines in the spectrum of sunspot umbra

Abstract

A high resolution spectrum of a sunspot umbra is used for identification of rotational lines due to (0, 0) band of the A 2Π–X 2Σ+ system and (0, 0), (1, 1), and (2, 2) bands of the B 2Σ+–X 2Σ+ system of the molecule SrF. The published sunspot umbral spectrum obtained with Fourier Transform Spectrometer and solar telescope of National Solar Observatory/National Optical Astronomy Observatory at Kitt Peak was used for the study. The new identification of more than 200 SrF lines in the umbral spectrum confirms that this molecule accounts for the majority of lines in the spectral range 15050 to 15360 cm−1 and 17240 to 17300 cm−1. Equivalent widths have been measured for well-resolved lines of these bands and the effective rotational temperatures have been estimated for which the presence is confirmed.