posted on Feb, 27 2005 @ 11:50 AM
If you thought that sun will be big when it becomes red giant and swallows earth few billions years to future or that propably the most known red
supergiant, Alpha Orionis aka Betelgeuze which would extend to halfway between Mars and Jupiter inside our solar system is huge you're wrong.
Team of astronomers from Lowell observatory has something better...
Red supergiants KW Sagittarii, V354 Cephei and KY Cygni, which all have diameter 1500 times the sun's.
If put to our solar system they would extend to halfway between Jupiter and Saturnus.
But considering biggest stars in scale of mass they don't even reach "median weight" with their ~25 solar masses while still being much above
Betelgeuze's ~15 solar masses. Current heavyweight champion is blue "hypergiant" called LBV 1806-20 which has mass 150 to 200 times the sun's.
Also despite of their huge size they're not the brightest ones with their luminosity being only couple hundred thousand times the sun's. That's
because cooler surface of red giants radiates considerably less energy per surface area than surface of hotter stars.
Good examples are blue supergiants Beta Orionis aka Rigel (~17 solar masses) with its luminosity ~60 000 times the sun's and diameter little under
100 times sun and Alpha Cygni aka Deneb (~25 solar mass) with luminosity of at least 60 000 suns (closest distance), possibly even equal to these
"XXXL sized" stars if closer to farthest distance while having diameter only couple hundred times the sun's at most.
But because more mass means more heat all these are dwarfed by LBV 1806-20 which is champion of also this contest with its luminosity being at least 5
million suns in minimum with upper limit around 40 million times the sun's. (star is also variable)