The rotational temperatures of Silicon hydride isotopomer lines in sunspot umbrae

The published sunspot spectrum obtained with National Solar Observatory/Kitt Peak laboratory’s high signal to noise ratio telescope and high resolution Fourier Transform Spectrometer were used for the study. A search was made for the prominent lines of the (0, 0) and (1, 1) A2Δ − X2Π for Silicon hydride isotopomers which lie between 23500 cm−1 and 24500 cm−1. The presence of lines from the (0, 0) and (1, 1) A2Δ − X2Π transition of SiH molecule coincided with the sunspot umbral lines suggest that Silicon hydride appears to be a non-negligible component of sunspot umbrae. However, the presence of A2Δ − X2Π (0, 0) and (1, 1) bands of SiD was found to be doubtful because of the lack of number of well identified lines in sunspot umbral spectra. Equivalent widths have been measured for well-resolved lines and, thereby, the rotational temperatures have been estimated for the band systems for which the presence is confirmed.

► The presence of SiH molecular lines in spectra of sunspots was examined. ► The new identification of 218 SiH lines were identified in the spectrum of sunspot umbrae. ► Identified lines suggests that SiH appears to be a non-negligible component in sunspots. ► The rotational temperature range is 1605 ± 426 K to 2062 ± 438 K.