How do i find the composition of a star? The lines on the star spectrum are purple with a wavelength of 410 nm, purple with a wavelength of 415 nm, blue with a wavelength of 435 nm, green with a wavelength of 500 nm, green with a wavelength of 550 nm, yellow with a wavelength of 580 nm, red with a wavelength of 696 nm, and red with a wavelength of 705 nm