text: The Doppler shift is used to detangle spectral lines for the spectroscopic variety of these systems.
full_question: The Doppler shift is used to detangle spectral lines for the spectroscopic variety of these systems. The first indirect evidence of gravity waves came from observations of this type of system. That example of this type of system was the first discovered to contain a pulsar and was discovered by (*) Hulse and Taylor. Algol, a system of this type, is the name of a paradox in stellar evolution in which mass transfer can alter a star's evolutionary track. Every instance of a type Ia supernova has originated from this type of system. For 10 points, name this type of astronomical system, such as Sirius, in which two stars orbit each other.
first_sentence: The Doppler shift is used to detangle spectral lines for the spectroscopic variety of these systems.
raw_answer: binary star system [or binary pulsar; prompt on pulsar before it is mentioned] 