<p>The Wikipedia article says that Spica A has 8 times the luminosity of Spica B (presumably that's at maximum.)  Magnitude is -2.5*log<sub>10</sub>(I/I<sub>0</sub>). So if the combined magnitude is 0.97, the magnitude of component A is ~1.1 and the magnitude of component B is ~3.3.</p>

CC BY-SA 4.0
2018-05-31T16:33:17.767Z
2018-05-31T16:33:17.767Z
Mark Olson
<p>What would be the (theoretical) apparent visual magnitudes of Spica A and Spica B (since they are too close together to be resolved telescopically)?  The Spica System is 77 parsecs away, and the combined apparent visual magnitude of the two stars is 0.97 at maximum (presumably when the stars are not eclipsing each other).  Their orbital parameters and respective luminosities, temperatures, and radii are given on Wikipedia: <a href="https://en.wikipedia.org/wiki/Spica" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Spica</a> </p>

<binary-star><apparent-magnitude><magnitude>
What are the apparent visual magnitudes of Spica A and Spica B?
Nicole Sharp
# What are the apparent visual magnitudes of Spica A and Spica B?

(Asked by: username_0 on 2018-05-31)

What would be the (theoretical) apparent visual magnitudes of Spica A and Spica B (since they are too close together to be resolved telescopically)? The Spica System is 77 parsecs away, and the combined apparent visual magnitude of the two stars is 0.97 at maximum (presumably when the stars are not eclipsing each other). Their orbital parameters and respective luminosities, temperatures, and radii are given on Wikipedia: <https://en.wikipedia.org/wiki/Spica>

**Tags:** binary-star, apparent-magnitude, magnitude

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## 1 answers

### Answer by username_1 on 2018-05-31. Score: 1 | Accepted answer

The Wikipedia article says that Spica A has 8 times the luminosity of Spica B (presumably that's at maximum.) Magnitude is -2.5\*log10(I/I0). So if the combined magnitude is 0.97, the magnitude of component A is ~1.1 and the magnitude of component B is ~3.3.


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