← back to the Substrate Record
qid 9962 · physics
Question: Two double stars of the same mass as the sun rotate about their common center of mass. Their separation is 4 light years. What is their period of revolution?
- 5$10^7 \mathrm{yr}$
- 1.5$10^8 \mathrm{yr}$
- 1.1$10^8 \mathrm{yr}$
- 2$10^8 \mathrm{yr}$
- 9$10^7 \mathrm{yr}$
- 7$10^7 \mathrm{yr}$
- 1.2$10^8 \mathrm{yr}$
- 1$10^8 \mathrm{yr}$
- 6$10^7 \mathrm{yr}$
- 8$10^7 \mathrm{yr}$
Our answer: E. 9$10^7 \mathrm{yr}$ Source quote machine-checked (exact quote)
How it was answered
Stored method, replayed by code (kind: formula)
Current source
Wikipedia, "Binary star"
https://en.wikipedia.org/wiki/Binary_star
“The mass of a star can be directly determined only from its gravitational attraction. Apart from the Sun and stars which act as gravitational lenses, this can be done only in binary and multiple star systems, making the binary stars an important class of stars.”
Source quote machine-checked (exact quote)
Earlier version (superseded)
https://en.wikipedia.org/wiki/Binary_star#Orbital_period
Source weak (http_get_200_text_and_question_terms)
Earlier version (superseded)
No public source has been found for this card yet (2 places checked internally).
If you have a Citable Source to dispute or challenge this, ADD IT so we can correct the answer by appending, never deleting. — hello@lianabanyan.com