Spectral Lines of the Circumstellar Gas of Ophiuchi 51

Ophuichi 51 contains a circumstellar, or star-orbiting, disk of dust and gas that will eventually condense into one or more rocky planets like those found nearest the sun. Such protoplanetary disks are relatively common; what makes Ophuichi 51 exceptional is the fact that some of the material is accumulating onto the star itself and can be observed in the spectra of its atmosphere. By studying the absorption lines of this pre-main sequence star, the elemental components of the dust can be determined, as each line corresponds to a unique atomic energy transition. Knowing what elements are present and in what distributions reveals the likelihood of that gas producing a possibly life-bearing planet. Using the software collection IRAF, the spectra are graphed on a plot of wavelength versus intensity. This makes it easier to recognize and analyze absorption lines, which appear as sharp downward spikes. The center of each of these spikes is recorded and compared to a list of known lines in order to identify which transitions are present. The Doppler shift resulting from the circular motion of the dust around the star is also accounted for. Next, each line’s equivalent width, or the area above the spike, is measured. The equivalent width is proportional to the column density, a gauge of the abundance of a particular transition. Together, these quantities help establish if planets that form from the dust and debris surrounding Ophiuchi 51 could engender life, as well as further understanding on late-stage planet formation.