I am considering a system with a primary star and a secondary star. The secondary star orbits the primary star very much like a planet, that means with a somewhat big distance from the primary star. The primary star would be a massive star, i.e. VY Canis Majoris, one of the biggest stars in the observable universe. The secondary star would be like our sun and have planets on its own. There are two interesting outcomes:

  1. Since the habitable zone of VY Canis Majoris is bigger than the solar system itself (at least according to Universe Sandbox²), almost every position of the secondary star system would be habitable even if it isn't in the habitable zone of the secondary star system.

  2. There would be an interesting day length variation across the year. Depending on the position/time of the year, the earth could have normal nights, nights that are half as short as on earth to nonexistent nights altogether.

Would it be possible for life to evolve in such an environment, since most of the time night would be very short, thus temperatures would/could be high. Though on the other hand, one could variate the distances, so that temperatures would be never too high.

  • $\begingroup$ I'm unsure what question is actually being asked. $\endgroup$ – bowlturner Mar 11 '16 at 17:09
  • $\begingroup$ I'm asking whether someone did research on that, like the one person who looked at the hypothetical torus-shaped planets. For example, would it hinder or benefit life to have such a system and in which ways? Maybe there are consequences, which I didn't thought of, which could make life impossible. $\endgroup$ – Arhama Mar 11 '16 at 17:36
  • $\begingroup$ @Arhama I've made an edit to your question to focus on the question at the end. General "has anybody done research on this topic?" questions don't work well on Stack Exchange; instead of asking about research in general, ask the question you want to answer (the one for which you would consult that research), and people can present any relevant research in the process of answering. If I've misunderstood your question please edit further. If you haven't already, you might want to check out our short tour for more about how the site works. Thanks and welcome! $\endgroup$ – Monica Cellio Mar 11 '16 at 19:41
  • $\begingroup$ Related, on how the light/seasons work in a system like this: worldbuilding.stackexchange.com/q/25318/28 $\endgroup$ – Monica Cellio Mar 11 '16 at 19:42
  • $\begingroup$ I think this is a little bit too broad. Anyway, You have to take into account that the planets will be receiving heat from both sources, so there will be a specific habitable area in between the two. Also, there are a lot of stable configurations this way. Probably. Which means we need to know the specifics of what you want in your system, more about your requirements, or a little more info on what you really want to know. And then you should ask instead whether it would be possible t have habitable planets this way. $\endgroup$ – Xandar The Zenon Mar 12 '16 at 4:20

So, the main question here is how likely life is to evolve in a situation like this (assuming a stable orbital system). The answer? Not going to happen.

The green band is definitely do-able, though you'd get some really, really weird seasons. "Summer" would be defined as the time when the sun(s) never set, "Winter" would be when the two suns are lined up and you actually get a half-day of darkness. You would, of course, need to be a minimum safe distance from the secondary star in order to not have your water boil off, but finding the Goldilocks spot would be possible.

The problem, as it turns out, is not with the arrangement of the system. The problem is the Hypergiant you are hanging out in close proximity to. Hypergiants have...problems.

The first problem they have is that their ridiculously high energy levels are such that it can exceed the Eddington Limit. The Eddington Limit is the point at which the star's luminosity is so great that the radiation pressure pushing the star outward meets the gravitational force holding the star together. A Hypergiant like VY Canis Major is literally so bright that it is blowing itself apart. It is estimated that at this point, Canis Major has shed nearly half of its original mass in this way, hurling it away as a sort of super solar wind. If our planet was far enough away, it may be able to survive this particle onslaught and, as you said, the habitable zone for VY Canis Major is very, very large.

The second (and most critical) problem is that they don't last very long. The lifespan for hypergiant stars is measured in millions of years, as opposed to the tens of billions for sun-like stars, and much longer for red dwarfs. So, lets assume an absolutely ideal situation...suppose our Hypergiant, its orbiting star, and the planet candidate all formed within a few years of each other (the bigger star would have formed first, and gobbled up most of the material, only leaving a smaller amount for the secondary star.) So, let's suppose everything happened just right.

It is estimated that our sun is about 4.6 billion years old, and Earth is supposed to be about 4.54 billion years old. As we are the only standard we have for the formation of life, we have to use our own development timeline. On Earth, the most basic prokaryote-like life supposedly formed 2.9 to 3.5 billion years ago. This means that the sun had already existed for between 1.1 and 1.7 billion years by the time the most basic of life was forming. This is far in excess of the life expectancy of a hypergiant. Furthermore, it took us about 4.54 billion years to reach the point of 'advanced intelligent life,' which is immensely beyond the lifespan of such a star.

In fact, the time between the formation of the Earth and the theorized 'great impact' that created the moon is too long (~500 million years).

So, there's why it couldn't happen...the star would have lived its brief, extremely violent life all the way from birth to whatever horrific death awaited it (probably a hypernova that would obliterate its child star before it collapsed into a black hole) long before life could have evolved around it.

Supergiants are a little better, but still tend to go boom after only about 30 million years. Still not anywhere close to long enough.

  • $\begingroup$ This is actually an interesting question, I also wonder what would happen to hypothetical habitable planets orbiting Alpha Centauri B when A dies, since A is more massive it will die first, but I wonder if the habitable planet/planets could survive around B when A enters the red giant stage $\endgroup$ – Stephanie Mar 26 '16 at 22:49

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