A planet orbiting a white dwarf. A planet seven times bigger than her: that’s what a team of researchers from the Instituto de Astrofísica de Canarias and other international centers they just discovered using NASA TESS data, the Spitzer telescope and the Gran Telescopio Canarias (GTC).
While the star (WD 1856 + 534) is around 40% larger than Earth, the planet (WD 1856 b) is approximately the size of Jupiter and orbits around it every 34 hours. To get an idea of the speed, it is enough to realize that Mercury takes 60 times longer to do it around the Sun.
Giant planets, dwarf stars
The case is very interesting because, as far as we know, the “painful birth” of a white dwarf leads to the destruction of nearby planets and, in practice, almost any object that approaches it ends up very badly stopped by the enormous gravitational force exerted by these space objects. At the end of the day, it is almost literally as if we were inflating a Sun like ours until it exploded and then concentrating much of its mass in the size of an Earth and a half.
Yet 80 light-years from us, the WD 1856 b has managed to get close enough to the star and stay in tip-top shape. So the doubt, therefore, is how it got there without being destroyed by the explosion of the red giant, ejected from orbit or engulfed.
Astrophysicists Theory is that the planet could have originated at least 50 times further from where it is now. Far enough not to die scorched and that, later, by various mechanisms, it would have been approaching WD 1856 + 534. Be that as it may, the system will allow us study new approaches to study the transit of planets into stars like this, too old and tired to give us a useful light to use with routine procedures.