Usually when star like sun die means run out of fuel, will pull nearby asteroids and planets inward and crushed them and will create a disk of debris that surrounds the planet. But this is first planet that made the whole journey intact.
NASA researchers announced last week that they have discovered a planet orbiting a white dwarf star and that is confirmed by NASA's satellite TESS( Transiting Exoplanet Survey Satellite ) and Spitzer Space Telescope.
Planet named WD 1856 b orbiting a small white dwarf star( WD 1856 ) which is 80 light years away from Earth in Draco Constellation. The planet WD 1856 b, is a gas giant roughly the size of Jupiter and carry 14 time more mass from Jupiter. Star containing sun's half mass and size slightly larger than earth.
According to NASA, it circles the star very closely and makes a complete orbit about every 34 hours. Vanderburg says in the NASA statement "WD 1856 b got very close to its white dwarf and managed to stay in one piece". As we know anything comes close to white dwarf will be crushed because of the star's immense gravity.
Credit: Video from NASA website (https://www.nasa.gov/).
In universe there are billion of star , every star lives because of nuclear fusion. Mostly fusion happens in core of star but sometimes that it also happened in place near core called shells.
If somewhere a star take birth so somewhere a star will be dead. Death of star depends on its mass. Star which have huge mass will be form as neutron star or black hole after death but which have less mass will be form as white ball who shines for trillion of years they are called White Dwarf.
As star grow old fusion will happen in different areas of star and different materials formed in this process this is known as Stellar Evolution . But every star has its time , when it's gravitational force is not upto the level to continue nuclear fusion in star which causes to start of process of dying a star. Since there is no external force (as fusion stops) so star will shrink because of it's gravitational force but it shines as material inside it is very hot. White dwarf still carries great mass like 1.4 solar masses that is called ChandraShekhar Limit and size of white dwarf is same as earth, because of it's small size and shine looks white in color it is called White Dwarf.
Because of smaller size and less light to find out object like this is not easy but scientist have two ways to find out:
1- Note the strange motion ( slight back and forth motion ) of companion star:
Companion star do slight back and forth motion because of hugs gravity of white dwarf and if we see reflected light from the object with the help of telescope then it'll be white dwarf other wise it'll be a black hole.
A bright star we see in sky is SIRIUS has also white dwarf neighbour called SIRIUS B.
2- Search white dwarf star with the help of planetary nebula:
when fusion stops in core of star , helium present in it's shell start burning called helium shell flash because of helium burns a shockwave is generated called thermal flash , release matter of star in space (this scene looks beautiful) called planetary nebula , so when we see a nebula a white dwarf will present in middle of it.
White Dwarf size equal like earth still they contain 1/2 mass of star that makes it very dense means if you take 1 teaspoon of matter of it it'll be equal to car's mass. It's surface gravity 1 lakh times more than earths, (if you land here you'll be crushed already). So don't think about it :).
Can we find a habitable planet near it? 🤔🤔...Yeah may be but with certain condition. The distance between sun and earth is nearly 15 crore km but if we find a habitable planet near white dwarf distance will be between them is 1 to 3 crore km. But most of times if planet is too close to white dwarf then it'll be tiddly locked means it'll not orbit in it's own axis and in that case front side which will facing toward star will be too hot and back side will be too cold. So only middle portion is only place where life can be found.
White dwarf are hotter object in universe because heat trap inside it and can only be emit through radiation, but because of empty space in universe this process took trillion of years that why scientist called white dwarf last hope for life.
When light and heat ends in white dwarf that will be last stage of star called Black dwarf but it still contains huge mass and they can achieve absolute zero temperature and they'll be most cooler object in universe.
Comments
Post a Comment