Intro: The term 'Exoplanet' means the planets which resides outside our solar system or the planets which doesn't orbit our sun most of them orbits another star/stars , some of them are just starless wanders out in the space between the stars and such starless wanders are known as 'Rogue Planets' . As they orbit other stars they are extremely far away from us most of them are so far that we can only dream about exploring them with our space probes . So let's get deep into this topic called Exoplanets
As far we know there are more exoplanets then the stars in our universe are you shocked ? Lets keep it simple . We have billions of planetary system just in our galaxy which is 100000 light years wide ( 1 light year ~ 9.5 trillion km) and there are approximately 2 trillion galaxies in our observable universe so you can imagine how many planetary system are there in our observable universe .
Exoplanets are super hard to detect as they are extremely far , small and much fainter as compared to their host star but thanks to our technology that with the help of our magnificent telescope we were able to study very few of the exoplanets . So here's the list of some of the interesting exoplanets :
1. Proxima Centauri B
It is the closest exoplanets to our blue planet which orbits its host star 'Proxima Centauri' despite being the closest it's still quite far , this planet resides 4.2 light year away from us and our farthest interstellar probe Voyager 1 which is approximately 158 Astronomical Units away from us ( 1 AU ~ 149.5 million km , an AU is defined as the distance between earth and the sun) travelling at speed of approximately 17 km/s will take nearly 73,000 years to reach near our closest exoplanet .
Host star of this planet is a Red Dwarf Star one of the most common type of star in our milky way galaxy . Proxima B is an interesting exoplanet as it share many similarities with earth and also vast differences , Proxima B has a mass of 1.27 times as that of earth and has a same size as earth and resides near the Goldilocks zone of its host star ( Goldilocks zone is a suitable area in the space where temperature is not too hot and not too cold , any rocky planet that orbits its host star in this zone could possibly sustain life and liquid water ) but it is also tidally locked with its star i.e. just like Venus
It can't rotate but just revolve around its sun and its one side will face darkness forever and other side will be continuously bombarded with light . Because it has same mass and size as earth scientists believe that it could be terrestrial rocky planet .
Now as it is a rocky planet and is near the Goldilocks zone it could possibly have liquid water and life on its surface but it's unclear till now that does it have a thick atmosphere or not . Despite being near the Goldilocks zone it is really close to its host star and completes one orbit in 11 earth days , so the radiations coming from its star might have ripped its atmosphere making it impossible for this alien world to hold liquid water but there's still hope because if Proxima B has a strong magnetic field then the harmful radiations could be deflected away from its magnetic field . Well to find this out we need to reach Proxima B first which requires a little bit of patience .
WASP-76B is an exoplanet orbiting the star WASP-76 located 640 light years away from us in the constellation Pisces . It is the only planet in WASP-76 system as of now , it is a gas giant and its mass 0.92 times the mass of Jupiter and its size is 1.8 times the size of Jupiter . Crazy thing about this exoplanet is that it is extremely hot , the surface temperature of this planet is around 1,920 degree Celsius reason for such a high surface temperature is because this planet orbits its host star within 1.8 earth days and is extremely close to its host star , the distance between WASP-76B and WASP-76 is around 0.033 AU just for comparison Mercury is ten times more father from our Sun than WASP-76B is from its host star , and WASP-76 is Main sequence star bigger than our Sun .
WASP-76B can trap almost 94% of the radiation emitted by its host star . Also this planet rain's molten iron and each iron drop has a temperature of around 2,400 degree Celsius . And like our Venus this planet is also tidally locked with its parent star which means its one side will completely be exposed to radiation and other side will face eternal darkness . So isn't this planet interesting .
3. HD 189733B
This is a gas giant planet that orbits a K-type star ( orangish coloured stars that are slightly cooler than our sun ) located 64.5 light years away from us in the constellation of Vulpecula. Its mass is around 1.13 times the mass of Jupiter and it takes 2.2 earth day to complete one orbit around its star . Interesting fact about this exoplanet is that it rains glass here and due to its mass it has a very strong gravitational pull due to which these glass rains are accelerated and ends up achieving the speed of bullet . Going to visit this planet will end up dying with million of cuts on the body .
COROT-7B is an exoplanet orbiting a K-type star COROT-7 located 489 light years away from us in the constellation of Monoceros it lies extremely close to its parent star ~ 0.017 AU away and completes one orbit of its star in 0.9 earth day . By this you have probably guessed the conditions on these planet , it absorbs 80% of the radiation coming from its host star . Its mass is 4 times the mass of earth , it is a rocky planet with its half of the surface covered with molten lava .
This planet is also tidally locked with its host star and its rains rocks and pebbles here with the 10% of speed of light (speed of light ~ 3,00,000 km/s) . As it is tidally locked its one side is exposed to all heat and radiation coming from its host star and this side is mostly covered up with molten lava on the other hand other side of this planet is experiencing freezing cold where you will end up freezing in few minutes . Because of this freezing cold on one side and rock melting surface temperature on the other side the speed of raining rock reaches up to 10% of speed of light which could puncher up our space shuttle .
CAROT-7B is slowly moving towards its host star and will end up getting engulfed by its host star ultimately going extinct and as it is moving towards its host star its surface temperature keeps on increasing with time .
J1407b is the first ever exoplanet found with ring and is also known as Super Saturn , it orbits its parent star V1400 Centauri located 433 light years away from us in constellation of Centaurus . It widely known for its ring . The rings of this planet are 640 times bigger than the rings of Saturn , if we replace Saturn with J1407b then its magnificent rings would be clearly visible in our night sky .
The radius of the rings of J1407b is near 19 million km . To hold such larger rings is nearly impossible for a planet , therefore there is a possibility that J1407b could be a brown dwarf ( despite of being bigger than the gas giants brown dwarf are still not massive enough to trigger nuclear fusion in their core , mass of Brown Dwarfs lies around 13-80 times the mass of Jupiter ) . But till now scientists aren't able to explain the reason behind these massive rings , which makes this exoplanet more interesting .
TRES-2B is an exoplanet orbiting the star GSC 03549-02811 located 750 light years away from us . This planet has been identified as the darkest known exoplanet reflecting less than 1% of any light that hits it . Well this isn't because of its gravity but because of the chemical composition of its atmosphere due to which light gets absorbs .
After studying this planet deeply scientists have found that amount of chemicals present in its atmosphere aren't sufficient to absorb more than 99% of light and therefore it should reflect at least 20% of the light incident on it , Well this is still a mystery for scientists that how this planet can absorb such a vast amount of light .