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What is the mass of Cygnus X-1?

Your professor has posed another challenge question to your introductory astronomy class. The first student to come up with the correct answer using good scientific methods and resources available on-line will be excused from homework for the rest of the semester. You know there are lots of things you would rather be doing on your weekends than homework, so you are determined to get the answer first! The challenge question is: What is the mass of Cygnus X-1?

Info Click here for more information on Cygnus X-1 and its optical companion.

You immediately think of three possible ways to go about the problem. Choose one below to begin your investigation!

Experiment Click here to use Newton's Law of Universal Gravitation to solve directly for the mass of the star.
Experiment Click here to calculate the star's mass by estimating its volume and density.
Experiment Click here to take advantage of the fact that this star is in a binary system to calculate its mass.

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Imagine the Universe! is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

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Project Leader: Dr. Barbara Mattson
Curator: Meredith Gibb
Responsible NASA Official: Phil Newman
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This page last updated: Monday, 30-Jan-2006 12:11:59 EST