2 – Supernova; Before Black Hole
Supernova; Before Black Hole are the stellar events creating ripples in the space that are felt even millions and billions of light years away.
The Star to be Supernova; Before Black Hole
A Supernova; Before Black Hole can be kindled on; one of these by simply putting far more matter in, so the flare up rips the dead star apart, and this is a Type 1 Supernova. But let’s go back before the explosion and dead stars. Again these largest stars die very quickly, but they spend a long time just burning hydrogen and then a decently long time as an expanded giant burning helium too. During all of this they are often giving off huge amounts of matter, many times the amount of solar wind our sun produces.
Indeed here is where we need to consider the different masses of giant stars, because stars can change in mass. The mass lost by fusion of hydrogen into helium and sunlight. Our Sun emits about 1.5 megatons of material as Solar Wind per second, mostly hydrogen and a little helium. Now that’s a lot of material, enough that if you are hanging at Earth’s distance from the Sun in a spacesuit you would be getting hit by around a trillions such particles a second.
Our Sun loses mass at almost 3 times that rate from fusion itself. Between both the Sun loses something like a couple hundred million megatons of material a year, which as huge as it sounds, is still trivial compared to the Mass of Earth, which is around 30 million times that, let alone the Sun, at around 10 trillion times that. That mass leaves the Sun because it’s super-hot, and you can think of it as something like sweat evaporating off the Sun, carrying material away.
The bigger the surface, the more comes off, and the hotter it is, the more comes off. Indeed the most massive stars, the Wolf-Rayet Stars, can easily lose entire solar masses over their lifetimes. R126a1, a star in the Large Magellanic Cloud on the edge of our galaxy and the current record holder for most massive star known, at over 200 Solar Masses, is thought to have shed over 30 solar masses during its million year lifetime.
Supernova; Before Black Hole
So it is shedding material nearly a billion times faster than our own Sun does. That is very much at the high end, and there are several mechanisms for mass loss, but the critical elements are rotation and heat. The handy thing about bigger stars is they already produce a lot more solar wind and have much hotter surfaces during their main sequence life. Only O-Type and hotter B-type main sequence stars, B0, B1, and B2-type can go Supernova, and surface temperatures range from 20,000 Kelvin for B2 stars all the way up to 50,000 Kelvin for the hottest O-type main sequence stars.
O-Type Stars are enormously bright, we estimate around 1 in 10 million stars are O-type main sequence, but several are naked-eye visible from Earth, in spite of only around 5000 stars visible to the typical human eye. These are not the brightest stars, that status belongs to those near the end of their lives, as they enter their own red giant, or rather supergiant and hypergiant phases.
The term ‘Red Giant’ mean all stars now burning helium or even carbon for fuel, but the color or spectral class can be any of them, be it a Red, “M-type” or a yellow G-type or Blue-White B-type. These produce even larger amounts of solar wind and at lower speeds, since the star is all expanded and less dense, so the escape velocity is lower. Stars off the main sequence are the easiest to harvest for mass as they have spread out so much their surface is barely gravitational bound to the star anymore.
But where these big stars are concerned that’s a pretty dangerous. Stars don’t go Supernova; Before Black Hole unpredictably, and the reason we can’t predict them precisely is because they are very rare anywhere near us close enough to get good observations and we have only been gathering real data on the lifetimes of such stars for maybe a human lifetime. There’s no reason to expect stars would go Supernova unexpectedly, or that those civilizations near one would even have to guess as to what year that would happen in.
Though since the key details are going on down under millions of kilometers of superhot gas, it probably helps to be better at neutrino detecting, as any given type of fusion will produce neutrinos of different speeds, so a sudden uptick in neutrinos associated with carbon burning or neon burning tells; it’s time to start getting out and a sudden uptick in silicon burning tell you it’s probably too late.
Destructive Power of Supernova; Before Black Hole
However, let’s not overdo the Destructive Power of Supernovae. Much like nuclear bombs, they are so associated with obliteration that we can forget that there is a range to which they are deadly and that range depends on not just their own strength but your armor. As an example, while you would need to worry about fallout, you are basically safe from the blast and detonation of even a typical hydrogen bomb if you are in a ditch or behind an earth embankment even just a few kilometers away.
So too, a Supernova; Before Black Hole does not blow all the planets in orbit around it into smithereens. You do not need to be too far away from a Supernova to ride out the explosion, indeed it’s a pretty good way to give a starship a speed boost out. If you were evacuating a system where a Supernova was expected and you could mark that time-zero moment down decently accurately and confidently then you would know exactly how close your spaceships, based on their design, could be and survive that explosion and even get a push from it.
Supernova; Before Black Hole do vary in strength but during the month or so they shine brightest; they tend to be on an order of 10 billion times brighter than our Sun, which means at 100,000 times the distance from them that Earth is, or 100,000 AU, they would be as bright as our Sun is, as 100,000-squared is ten billion, and light and blasts in space fall off in strength with the square of distance.
Of course 100,000 AU is pretty big, 1.58 light years, and 10,000 AU is much closer, especially given that stars capable of going supernovae are already thousands of times brighter than our own Sun even when on Main Sequence and require you to live hundreds of AU away from them even before they entered their supergiant phases.
Habituating System with Red Giants
Stars in these lifetime ranges are not going to offer you planets you can transfer because Earth-sized ones won’t have finished coalescing and cooling by the time their star dies. Now as to evacuating neighboring systems, that’s not a concern at all. Such destructive blasts could damage ozone layers of planets in neighboring systems but that is easily shielded against by spacefaring civilizations with advance notice.
These big stars are often clustered together in groups, tight packs where it isn’t 4 light years to the nearest star but light months or days or even minutes, as such colossal stars often have binary companions or are in multiple stars systems or even clusters. A star a thousand times more massive than another might need 1000 times as much push to get to the same speed, but if it is producing a billion times as much light and hence light pressure, it’s accelerating more than a million times faster.