How to detect planets beyond our solarsystem

459 views

Published on

gives a brief description of the some of the most popular( and easy to understand) ways of detecting planets that are presently employed by scientist all around the globe.

Published in: Technology
0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
459
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
14
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide
  • Spectrometers needs to be added
  • How to detect planets beyond our solarsystem

    1. 1. How to detect planets beyond our Solar system
    2. 3. THE SUN THAT WE KNOW THE SOLAR SYSTEM
    3. 4. THE NIGHT SKY The Night Sky
    4. 5. <ul><li>PLANETS derive their name from the term “Wandering Stars” </li></ul><ul><li>Planets have been known even to the early cultures. But were viewed as emissaries of god . </li></ul>
    5. 6. Mayan Astronomy The stone henge
    6. 7. Astronomers star gazing
    7. 8. Intensive telescope search (1930) - based on incorrect prediction! Predicted by Newtonian Mechanics (1846) “ Naked Eye” planets Telescope (1781)
    8. 9. <ul><li>Only few planets are visible to the unaided eye , while most remain undetected </li></ul><ul><li>Hence astronomers use indirect methods to discover planets beyond our Solar system. </li></ul>
    9. 10. <ul><li>THE METHODS INCLUDE: </li></ul><ul><li>Transit method. </li></ul><ul><li>Radial velocity method. </li></ul><ul><li>Pulsar timing. </li></ul>
    10. 12. TRANSIT METHOD <ul><li>One of the simplest methods </li></ul><ul><li>Uses fundamental concepts like: </li></ul><ul><li>Concept of eclipse </li></ul><ul><li>Variation in luminous intensity during eclipse </li></ul><ul><li>Parallax method. </li></ul>
    11. 14. Understanding transiting motion <ul><li>The luminous intensity of the star observed by us changes when planet transits before the parent star. </li></ul>
    12. 15. <ul><li>Variation in the intensity α The size of planet. </li></ul><ul><li>Luminous intensity of star HD209458 dims by 1.7% </li></ul>
    13. 18. Applications of transit method <ul><li>Determining the radius of the planet. </li></ul><ul><li>Makes use of light curve and parallax method </li></ul>
    14. 19. <ul><li>2. Study of planets upper atmosphere. </li></ul><ul><li>Light emanating from the upper atmosphere is studied under high resolution stellar spectrum. </li></ul><ul><li>Thus detecting elements in the atmosphere. </li></ul>
    15. 22. <ul><li>3. Temperature of the planet </li></ul><ul><li>Observed during secondary eclipse(when planet behind the star). </li></ul><ul><li>Original light signal of star is obtained . </li></ul>
    16. 23. Light intensity of planet = a-b a= light intensity during secondary eclipse b= intensity with planet transiting the star
    17. 24. <ul><li>The reading estimates the temperature and </li></ul><ul><li>Possibility of cloud formation. </li></ul>
    18. 25. Temperatures of various planets found using Transit method
    19. 26. <ul><li>Could this indicate presence of life.......................? </li></ul><ul><li>............Well the research </li></ul><ul><li>is going on </li></ul>
    20. 27. ADDITIONAL INFORMATION <ul><li>Temperature of some exoplanets: </li></ul><ul><li>TrES-1 = 1060k. </li></ul><ul><li>HD209458 = 1130k. </li></ul>
    21. 28. <ul><li>DISADVANTAGES OF TRANSIT METHOD </li></ul><ul><li>1.Planets need to be aligned with the astronomer’s vantage point. </li></ul>
    22. 29. <ul><li>Only about 10% of planets with small orbits have these alignment and this percentage decreases with size of the planet. </li></ul><ul><li>Probability of random alignment producing transit is mere 0.47% </li></ul>
    23. 30. <ul><li>This method suffers from high rate of false detection. </li></ul><ul><li>Hence transit method requires additional conformation </li></ul><ul><li>AND…….. radial velocity method provides this ! </li></ul>
    24. 31. THE RADIAL VELOCITY METHOD
    25. 32. RADIAL VELOCITY METHOD <ul><li>Radial velocity method too makes use of basic concepts such as : </li></ul><ul><li>1.Centre of mass. </li></ul><ul><li>2.Spectral lines. </li></ul><ul><li>3.Radial velocity. </li></ul><ul><li>4.Dopplers effect. </li></ul><ul><li> </li></ul>
    26. 34. <ul><li>The motion of the planet and star system </li></ul>
    27. 36. <ul><li>A system of parent star and it’s planets is studied , with planet moving around the star. </li></ul><ul><li>Parent star wobbles(spins around the common cm) </li></ul>
    28. 37. <ul><li>During primary eclipse star moves towards us . </li></ul><ul><li>During secondary eclipse the planet tugs the star away from earth. </li></ul>
    29. 38. <ul><li>Starlight so obtained during this motion is studied under a spectrograph. </li></ul><ul><li>The absorption lines so obtained exhibit variation in the radial velocity of the star </li></ul>
    30. 40. <ul><li>These stellar spectral lines shift </li></ul><ul><li>towards the red end of spectrum as star moves away from earth </li></ul><ul><li>And towards the blue end of spectrum as it moves towards the earth </li></ul>
    31. 41. Variation in the radial velocity being measured
    32. 42. An actual observatory
    33. 43. <ul><li>The variation in the velocity up to 1m/s can be measured with modern spectrometers example: HARPS,HIRES etc. </li></ul>
    34. 44. HIRES
    35. 45. <ul><li>Radial velocity method has been the most productive technique used by planet hunters. </li></ul><ul><li>This method determines minium mass of the planet. </li></ul>
    36. 46. <ul><li>LIMITATIONS </li></ul><ul><li>Only sensitive towards large Jupiter sized planets. </li></ul><ul><li>Insensitive towards rocky </li></ul><ul><li>planets. </li></ul><ul><li>Large investment of time & </li></ul><ul><li>resources </li></ul>
    37. 47. Few planets discovered using radial velocity method
    38. 48. THE PULSAR TIMING
    39. 49. <ul><li>Pulsars are dense remnant </li></ul><ul><li>of stars that exploded as </li></ul><ul><li>supernova. </li></ul><ul><li>Pulsars emit electromagnet </li></ul><ul><li>radiations at regular </li></ul><ul><li>intervals. </li></ul>
    40. 50. <ul><li> Slight anomaly in the timing of the radio pulsars is. used to track the pulsar’s motion This forms the basis of pulsar timing. </li></ul>
    41. 51. Working of the pulsar motion
    42. 52. <ul><li>Pulsar timing is very sensitive method </li></ul><ul><li>Can detect planets as small as a 10 th of the earth’s mass. </li></ul>
    43. 54. Limitations <ul><li>Pulsars are rare to find in the universe hence it’s to detect planets is restricted </li></ul><ul><li>The surrounding of pulsars contains intense em radiation, which is unsuitable for life forms. </li></ul>

    ×