Exoplanet

NASA Artist concept of exoplanet beyond our solar system

What is Exoplanet? 

     Exoplanet ( exo - means outer or outer solar system ) is a planet outside solar system which orbits a star. The concept of exoplanet was made in the early 1917, but the first confirmed scientific discovery was made in 1992. After that 3,710 planets were discovered outside our solar system including 621 planetary systems. These discoveries were made by High Accuracy Radio Velocity Planet Searcher, Kepler Space Telescope and several other ground based telescopes. It has been found that many planet lie in the habitable zone from their native star. Major discoveries was Proxima Centauri-b and Proxima Centauri closest star to our sun.

 Indian Observatory in Exoplanet Detection:

     The first involvement and report of existence of exoplanet was made by William Stephen Jacob at Madras Observatory controlled by English East India Company in 1855. Similarly in the year of 1890 another astronomer Thomas J.J.See from the University of Chicago stated the existence of 70-Ophiuchi system with 36-years of orbital period. Later, astronomer Forest Ray Moulton published a paper on three-body system with their orbital parameters.

 Detection Techniques:

• Direct imaging
• Gravitational microlensing
• Polarimetry
• Astrometry
• Radial velocity
• Pulsar timings variations
• Transit photometry etc..

 Most Amazing Discovery of exoplanet:

TRAPPIST-1 System :  
     
    NASA had made wonderful discovery of Trappist-1 system which is the best discovery of Hubble Space Telescope and NASA. Now, if we want to know more about the existence of life beyond the solar system, we need to know the age of the star. Young stars have frequent releases of high energy radiation called flares that can zap their planets. If a new planet is born then the orbit of that planet would be unstable.On the other hand, planets orbiting older stars have survived the spate of youthful flares, but have also been exposed to the ravages of stellar radiation for a longer period.

Now NASA's Scientists have a good estimate for the age of one of the most intriguing planetary systems discovered to the date called Trappist-1 System. A system of 7 earth seized planet orbiting a star which is nearly 40 million light years away from the earth. Researchers said that new study reveals that the star is too old between 5.4 to 9.8 billion years ago.

The seven wonders of TRAPPIST-1 were discovered using Transisting Planets and Infinitesimals Small Telescope (TRAPPIST) in Chile, Spitzer Space Telescope of NASA, and other ground based telescopes.

Trappist-1 is 13.7 billion years old in age than the universe and it is like a slow-burning candle that will shine for about 900 times longer than the current age of the universe.

In 2017, more than 139 exoplanets have been discovered.
Exoplanets discoeverd in 2017.

Tags: Exoplanet | Space facts

More Links:
 Top 5 high cited research papers on Exoplanet:

• Borucki, William J., et al. "Kepler planet-detection mission: introduction and first results." Science 327.5968 (2010): 977-980.
•  Charbonneau, David, et al. "Detection of planetary transits across a sun-like star." The Astrophysical Journal Letters 529.1 (1999): L45.
• Charbonneau, David, et al. "Detection of an extrasolar planet atmosphere." The Astrophysical Journal 568.1 (2002): 377. 
• PHASE, COMMISSIONING. "Setting new standards with HARPS." The Messenger 114 (2003): 20  
• Charbonneau, David, et al. "Detection of thermal emission from an extrasolar planet." The Astrophysical Journal 626.1 (2005): 523.

Credits:

 

Image Credit : NASA

Journal Credits : google scholar

Text References : Exoplanet ( wikipedia) retrived 2017