combined magnitude

combined magnitude

The apparent brightness of two or more stars so close that they are observed as a single star. It is not equal to the sum of the individual magnitudes, m 1 and m 2, but is a logarithmic function:
m = m 1 – 2.5 log{1 + antilog[–0.4(m 2m 1 )]}

See magnitude.

References in periodicals archive ?
It's a pair of F5 stars a little larger and hotter than the Sun, about 63 light-years away and shining in our sky at a combined magnitude of 4.
Because of this the combined magnitude would have been approximately 5.
If more than one quake occurred simultaneously, the combined magnitude could be 8, the governmental committee said.
Only a combined magnitude is available for VV 102; the components are too tightly bound to measure separately.
I used differential aperture photometry in AIP4WIN to measure the combined magnitude of Ganymede and Europa assuming a magnitude of 5.
That impression is not as strong in images, but M37 still looks darned good: a mob of small stars in a roughly spherical shape with a moderately bright combined magnitude of 6.
At a size of 14' across, M37 is well framed in almost any telescope, and the bright combined magnitude of its stars, 5.
Their combined magnitude is almost exactly -5, which is equal to 100 zero-magnitude stars like Vega.
This would make the combined magnitude for the unresolved pair of compact, high-surface-brightness galaxies magnitude 14.
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