EXOPLANETS

By Pablo del Cerro, Marta Liébana & Alberto Rebollo.

Index• Introduction• History• ‘Types’ of exoplanets• Purpose?• Planet Habitability• Goldilock’s zone• Atmosphere• Chemical environment• Spectograph• Energy required for metabolism• Drake’s equation• Video• What is the importance of exoplanets?• Conclusion

INTRODUCTION

• An exoplanet is a planet that orbit a different star from the sun

• More than 1800 exoplanets have been discovered • Alpha Centuiri Bb nearest planet?• Almost all of the planets detected so far are within the Milky 

Way.• DENIS-P J082303.1-491201 b, about 29 times the mass 

of Jupiter

HISTORY

• At first scientist supposed that existed but they couldn’t prove it

• In the 16th century Giordano Bruno put foward the view that the other stars should have also planets like the sun

• The first confirmed detection came in 1992

``TYPES´´ OF EXOPLANETS

• The classification of exoplanet types is unfortunately arbitrary• Terrestrial Planet

Solar System Planets in the NameSize PrefixesHot and Cold terms

PURPOSE?

Although I could find more reasons, I think the best reason is, because we simply can!

Why do we spent our money in something that is thousands of millions of

kilometres away?

Planet Habitability

• Potential of a planet to develop and sustain life.• Largely agreed on an extrapolation of Earth’s

and Sun’s characteristics.

• HZ: Habitable zone.

NASA

Extended regions of water.

Favourable conditions for the assembly of complex organic molecules.

Energy sources.

Goldilock’s zone

• Shell-shaped region of space surronding a star.• Liquid water can appear.• Location depends on the energy the star is

outputting (inverse squared law).• Where temperature of the planet goes from 0-

100ºC.

Atmosphere Protecting the planet an inhabitans from radiation. Keep planet surface warm. Provide the planet with oxygen so life evolves.

• Contain some of the chemical elements necessary for life.

Chemical Enviroment

• Essential chemical elements.

• Water: Liquid, able to have pH.• Primary focus of astrobiological research.

Spectograph.

• Light reacts differently for each element.

• Depending on the peak on the spectograph, we can tell which element it is about.

• Valid for the atmosphere and the elements forming the surface.

Energy required for metabolsim.

• Solar: reaching the surface and near surface.

Perfect star: Stable variability and high metallicity.

• Geothermal: Subsurface.

Drake’s Equation

N = N* fp ne fl fi fc fL N* is the number of total stars in the Milky Way fp is the fraction of those stars that have planets ne is the number of planets per star that could be capable of sustaining

life. fl is the estimation of life actually evolving on the planets on which it is

capable to. fi is the estimation of intelligent life evolving. fc is the fraction of that intelligent life that would be capable of

communication. fL is the fraction of the life of the planet during which this civilization could

live.

BBC: Drake´s equation.

VIDEO• Direct discovery: nearby stars+ very large planets.• The majority have been discovered through

indirect methods.• 1. A planet passing in front of a star will make it

darker: the amount of darkness determines the size of the panet.

Transit of Venus (2012)

2. The center of mass is not at the centre of the star, which creates a tiny wobble in the velocity of the star.

Discovery of more than 1800 exoplanets as of 2014.

•

What is the importance of exoplanets?- What is the point in studying them?

-Is it worth the expense of money in it?

Conclusion

• An exoplanet is a planet that orbits a different star from the Sun.

• The first confirmed detection was in 1992.• An exoplanet habitability depends on the

following requirements: Extended regions of water, good conditions for the assembly of complex molecular particles and energy sources.

• They can be discovered by direct or indirect methods.