Can a star (the astronomical type) be arrested for planet abuse? Astronomers have discovered a newborn star that is quickly consuming a huge young planet as it orbits it at a speedy once-every-11-hours pace.
Astronomers at Rice University in Houston, Texas, were searching for young exoplanets that would most likely be orbiting young stars. Almost all of the 3,300 exoplanets discovered so far orbit so-called middle-aged suns like our own. Young stars are very active with outbursts, magnetic fields and starspots that can be mistake for planets.
Not this time. On May 26, Rice astronomer Christopher Johns-Krull announced the discovery of ‘CI Tau b’, a young gaseous planet approximately eight times the size of Jupiter orbiting the star PTFO8-8695 in the constellation Orion. According to his study in The Astrophysical Journal, the excitement of finding a planet orbiting such a young star was tempered by the fact that the young planet was being rapidly eaten by its own star.
PTFO8-8695’s star is about 1,100 light years from Earth and two million years old – an infant in star years. It’s so young, it still retains its circumstellar disk of gas and dust. That’s no reason for it to be chowing down on CI Tau b. Could it be that tight orbit swinging it too close to the hot tongue of a hungry baby star?
A handful of known planets are in similarly small orbits, but because this star is only 2 million years old, this is one of the most extreme examples.
That’s an affirmative from Johns-Krull, who says hot Jupiters – hot planets with large masses and small orbits – like CI Tau b are vulnerable to having their layers peeled off by the gravitational pull of their stars, especially in such close proximity orbits.
Is this astronomical soap opera going to end with CI Tau b being eaten to death by PTFO8-8695? Johns-Krull’s answer is cautious but concerned:
We don’t know the ultimate fate of this planet. It likely formed farther away from the star and has migrated in to a point where it’s being destroyed. We know there are close-orbiting planets around middle-aged stars that are presumably in stable orbits. What we don’t know is how quickly this young planet is going to lose its mass and whether it will lose too much to survive.
If it’s any consolation (or should that be constellation?) to CI Tau b, Billy Joel probably thinks only the good stars die young too.