Look at the night sky and see it filled with stars. But the naked eye can see only a microscopic fraction of them. Only one galaxy has 100 billion stars and galaxies in the Universe even more. Astronomers believe that in the world of the order of 10^24 stars. These powerful power plants come in different colors and sizes and is close to many of them our Sun looks like crumbs. But which star will be the real giant of the skies? You should start with the definition of what we mean by giant. Whether it’s the star with the largest radius, for example, or with the largest mass?
Galactic giants
The star with the largest radius is probably UY Shield, alternating bright supergiant in the constellation of the Shield. Located in 9500 light years from Earth and consisting of hydrogen, helium and other heavier elements, almost with the composition of our Sun, this star in the radius passes him in 1708 (plus or minus 192).
The circle of stars is about 7.5 billion kilometers. You have to fly for 950 years to fully fly around — and even so it takes light six hours and 55 minutes. If you replace our Sun with this, the surface will be somewhere between the orbits of Jupiter and Saturn. Of course, the Earth would not have been.
Given its huge size and possible weight, in 20-40 times higher than solar (2-8×kg), UY Shield will have a density of 7×10⁻⁶ kg/m3. In other words, it is billions of times smaller than the density of water.
In fact, if you put this star in the biggest water bath in the Universe, it would theoretically float. Being a million times less dense than the Earth atmosphere at room temperature, it also hung in the air like a balloon — unless, of course, to give her enough space.
But if these incredible facts already managed to surprise you, we haven’t started yet. UY Shield, of course, a big star, but not a heavyweight. The king of the heavyweights is the star R136a1, located in the Large Magellanic Cloud, 165 000 light-years.
Massive attack
This star, a sphere of hydrogen, helium and heavier elements, slightly more Sun, 35 times its radius, but more massive in its 265 times — that is remarkable, given the fact that 1.5 million years of her life she has lost 55 solar masses.
Type stars wolf — Rayet far from stable. They look like blurry blue sphere without a clear surface, blowing incredibly strong stellar winds. These winds move at the speed of 2600 km/s — 65 times faster than a probe “Yunona”, the fastest artificial object.
As a result, the star loses mass at a speed of 3.21×101⁸ kg/s, equivalent to the loss of the earth for 22 days.
Such space rock stars burn out quickly and die quickly. R136a1 emits nine million times more energy than our Sun, and would have seemed in ‘ 94, 000 times brighter than the Sun to our eyes if took his place. In fact, it is the brightest of the detected stars.
Its surface temperature over 53, 000 degrees Celsius (compare this to the temperature of the solar surface) and live such a star would not be more than two million years. Her death will mark a huge supernova that even after the black hole itself will not leave.
Of course, next to such giants our own Sun looks insignificant, but, again, it too will grow as they age. After about seven and a half billion years it will reach its maximum size and becomes a red giant and expands so that the current orbit of the Earth will be inside the star.
And yet these stars we find, after examining only a fraction of the Universe. What wonders await us?