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Stars that small are very stingy with their energy production, they burn fuel ever so slowly. This is a striking contrast with the supergiant star Betelgeuse that used up most of it's fuel so quickly in a short time that it's now about to go nova.
Aside from being a long-lasting star in itself, VB 10b will actually use it's companion planet as an energy source in the future when VB10b tightens it's orbit and moves closer to it's sun. Yes, VB 10b is literally a "spare gas tank" for it's parent star. Greg Laughlin says, "The planet's gas will be a shot of fresh hydrogen to VB10 and should give it enough fuel to burn another 100 billion years -- basically forever."
And when we say forever, in this context it means close to the end of the universe, perhaps the last age of the cosmos where entropy has almost taken over, long after most other objects have faded into darkness.