Astronomy C Question Marathon

[cellobix]

The orbit of an eclipsing binary system is oriented such that it is observed from directly edge-on. The system has a period of 68 hours, the secondary star has an orbital velocity of 72.5 km/s, and the eclipse of the primary star lasts 11 hours. What is the diameter of the primary star?

[Crazy Puny Man]

The orbit of an eclipsing binary system is oriented such that it is observed from directly edge-on. The system has a period of 68 hours, the secondary star has an orbital velocity of 72.5 km/s, and the eclipse of the primary star lasts 11 hours. What is the diameter of the primary star?

Is it just (Click to Show Hidden Text)

72.5 km/s * 11 hr * 3600 s/hr = 2.87 x 10^6 km?

[cellobix]

Nope.

[Crazy Puny Man]

Nope.

When you say "the eclipse of the primary," are we talking primary minimum, or when the secondary star eclipses the primary star?

Also, on an eclipsing binary light curve, is this 11 hours = T3 - T1? Or T4 - T1?

[cellobix]

When you say "the eclipse of the primary," are we talking primary minimum, or when the secondary star eclipses the primary star?

I am referring to the secondary star eclipsing the primary.

Also, on an eclipsing binary light curve, is this 11 hours = T3 - T1? Or T4 - T1?

I'm not sure what you mean by T1, T3, and T4, sorry.

[syo_astro]

When you say "the eclipse of the primary," are we talking primary minimum, or when the secondary star eclipses the primary star?

I am referring to the secondary star eclipsing the primary.

Also, on an eclipsing binary light curve, is this 11 hours = T3 - T1? Or T4 - T1?

I'm not sure what you mean by T1, T3, and T4, sorry.

He means like in: http://www.wallentinsen.com/binary/1-1_lightcurve.gif.

[cellobix]

Thank you syo_astro for clarifying. 11 hours = T3-T1.