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1. In 1995, Michel Mayor and Didier Queloz directly discovered the first exoplanet orbiting the star 51 Pegasi b, for which they were later awarded the Nobel Prize in 2019. 2. There are now over 4000 known exoplanets that have been discovered, showing that our solar system is not unique in having planets. 3. The three main methods for detecting exoplanets are: measuring the Doppler effect of stars, detecting planetary transits that dim starlight, and directly imaging exoplanets.
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lecture29
- 1. Introduction to modernastronomy 29 島袋隼⼠(Hayato Shimabukuro)（云南⼤学、 SWIFAR） ©GETTYIMAGES
- 2.
- 3. Remember how toform solar system.
- 4. Remember how toform solar system.
- 5. Planetary system Is oursolar system the only planetary system?
- 6. Michel Mayor Didier Queloz Discoveryof first exoplanet •In 1995, Queloz and Mayor directly discovered the first exoplanet which orbit 51 Pegasi b. •A Nobel prize was awarded for this discovery in 2019. No! The solar system is not the only planetary system.
- 7. Michel Mayor Didier Queloz Discoveryof first exoplanet •In 1995, Queloz and Mayor directly discovered the first exoplanet which orbit 51 Pegasi b. •A Nobel prize was awarded for this discovery in 2019. No! The solar system is not the only planetary system.
- 8. •Prof. Mayor heardthe news that he is awarded the Nobel prize at the cafeteria of airport.
- 9. Exoplanets We have alreadyfound more than 4000 exoplanets(系外⾏星). https:// exoplanetarchive.ipac. caltech.edu/ exoplanetplots/
- 10. Exoplanets • Queloz andMayor discovered an exoplanet that orbits main sequence stars in 1995, but other astronomers discovered exoplanets that orbit a pulsar by indirect method (Pulsar timing array). • These exoplanets that orbit a pulsar are the first discovered exoplanets. •But, Queloz and Mayor discovered the exoplanet more directly. Thus, they are regarded as the first discoverer.
- 11. How to detectexoplanet How do we detect exoplanets?
- 12. How to detectexoplanet How do we detect exoplanets? 1. Doppler effect
- 13. How to detectexoplanet How do we detect exoplanets? 1. Doppler effect 2. Planetary transit
- 14. How to detectexoplanet How do we detect exoplanets? 1. Doppler effect 2. Planetary transit 3. Direct image
- 15. 1. Doppler effect Howto detect exoplanet •When an exoplanet orbits a stellar star, the exoplanet’s gravitational force causes the stellar star to move slightly. •We can observe the Doppler effect of the spectrum from stellar stars.
- 16. 1. Doppler effect Howto detect exoplanet •When an exoplanet orbits a stellar star, the exoplanet’s gravitational force causes the stellar star to move slightly. •We can observe the Doppler effect of the spectrum from stellar stars.
- 17. 2.Planetary transit How todetect exoplanet •When exoplanets pass through a star (transit), the brightness of the star is reduced. •We detect exoplanets by the change of the light curve.
- 18. 2.Planetary transit How todetect exoplanet •When exoplanets pass through a star (transit), the brightness of the star is reduced. •We detect exoplanets by the change of the light curve.
- 19. How to detectexoplanet 3.Direct image •It is easy to understand. We take an image of exoplanets directly. Difficulties •We have to hide starlight because it is too luminous than exoplanets. •We require high spatial resolution( ). < 1′  ′  HR8799 planet planet planet planet HR8799 is located 130 light years from us.
- 20. Credit: ALMA 太阳 太阳 与太阳系的⽐较 An exoplanetis being formed
- 21. Exoplanet properties Exoplanet R Mass(M) R(AU) *MJupiter =1 What can you find the properties of exoplanets? http://exoplanet.eu/ 10 1 0.1 1e-2 1e-3 1e-4
- 22. Exoplanet properties Earth Jupiter •The massof exoplanets mostly ranged from 10−3 Mjup − 10Mjup •We call exoplanets that have 1-10 super-earth. The main components of super-earth are solid components such as rock and metals (similar to the earth!) Mearth
- 23. Exoplanet properties Earth Jupiter •The massof exoplanets mostly ranged from 10−3 Mjup − 10Mjup •We call exoplanets that have 1-10 super-earth. The main components of super-earth are solid components such as rock and metals (similar to the earth!) Mearth
- 24. Exoplanet properties Earth Jupiter •Semi-major axisof exoplanets are mainly ranged inside 10 AU, although some exoplanets have more than 10AU.
- 25. Exoplanet properties Earth Jupiter •Semi-major axisof exoplanets are mainly ranged inside 10 AU, although some exoplanets have more than 10AU.
- 26. Exoplanet properties Earth Jupiter •Planets withorbital semi-major axes less than 0.1 AU are said to be hot, while those on wider orbits are called cold.
- 27. Exoplanet properties Earth Jupiter •Planets withorbital semi-major axes less than 0.1 AU are said to be hot, while those on wider orbits are called cold. hot
- 28. Exoplanet properties Earth Jupiter •Planets withorbital semi-major axes less than 0.1 AU are said to be hot, while those on wider orbits are called cold. hot cold
- 29. Hot Jupiter Exoplanets thathave… •mass as similar as Jupiter •major-axis of 0.015au - 0.5au from main star. These exoplanets are called “Hot Jupiter” It is easy to imagine that the surface temperature of Hot Jupiter is too hot!(>2000K)
- 30. Size of exoplanets •Theradius of exoplanets mainly ranged from 0.3Rearth − 30Rearth •Many exoplanets are similar to solar system.
- 31. Size of exoplanets •Theradius of exoplanets mainly ranged from 0.3Rearth − 30Rearth •Many exoplanets are similar to solar system.
- 32. Size of exoplanets •Theradius of exoplanets mainly ranged from 0.3Rearth − 30Rearth •Many exoplanets are similar to solar system.
- 33. The mass distributionof exoplanets •We can find most of exoplanets have masses less than 10Mearth
- 34. The mass distributionof exoplanets •But, some exoplanets have mass larger than ! 10000Mearth •In order to understand these very massive planets, we need new planet formation theory.