T Tauri Stars

T Tauri stars are not really stars yet, but almost. They are young proto-stars, still contracting from a giant dense cloud of gas and dust, and heated mostly by the gravitational energy of contraction. Nuclear fusion of hydrogen into helium - the main power source for normal stars like the sun - has not yet begun. They have spectra that look like fairly normal sun-like stars, with spectral types F, G, K or M. They usually rotate with periods of one to twelve days, and are highly variable and active, because of large starspots, areas of powerful magnetic activity.

DM Tau

Below is a sonified video of some observations of a T Tauri star called DM Tau. During a span of 250 days, 64 observations were made of DM Tau. The video scans over time (x-axis) and modulates pitch based on magnitude (y-axis). Lower pitch represents dimmer magnitudes. The wide range of brightnesses that a T-Tauri star can exhibit during its growth phase is clearly heard.

Next, the observed spectrum of DM Tau is shown below as a sonified video. This video scans across a plot of brightness measured in flux or intensity of light (y axis) versus wavelength (x axis), moving from blue to red wavelengths from 3800 to 7200 angstroms. Lower pitch represents weaker flux. DM Tau is a dim red dwarf, therefore its spectrum peaks at redder wavelengths, and a gradual increase in flux can be heard as wavelength increases. Also notable is a strong emission line at 6562 Angstroms, called the H-alpha spectral line. Light of this wavelength is emitted when a hydrogen electron falls from its third energy level to its second energy level. T-Tauri stars emit strongly at this wavelength when material falls from their surrounding disk onto the central star.

The spectrum of DM Tau was provided by the FAST Spectral Archive. The light curve is an optical r-band from ASAS-SN.