{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture 18 - Planets Around Other Stars

Lecture 18 - Planets Around Other Stars - Planets around...

Info icon This preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Planets around other Stars ASTRONOMY 3 Lesson 18 1 Depiction of planets in orbit around the pulsar PSR 1257+12 (Credit: Robert Hurt, SSC)
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
NATURE of the Universe Review of Lesson 17 Astronomy - Planets around other Stars • The interstellar medium can get compressed into dark (molecular) clouds. Star formation starts when part of a molecular cloud becomes gravitationally unstable, and starts to collapse . • The contracting protostar heats up . Once it becomes hot enough to be observable in the infrared , the pre-main sequence phase starts. Protoplanets might form in a disk of gas and dust around the protostar, • Once density and temperature in the core get high enough , hydrogen fusion starts. The star is now on the main sequence . • The Orion nebula is a nearby region where star formation is taking place . 2
Image of page 2
NATURE of the Universe Questions from Lesson 17 Astronomy - Planets around other Stars Think about (questions from Lesson 17): • How do we know about planets around other stars? • Could (intelligent) life exist on extra-solar planets? 3
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
• Stars, Disks, and Planets • Indirect Detections: Doppler methods, astrometry, and transits • Direct Detection of Exoplanets • Life on Other Worlds? • Summary & Announcements NATURE of the Universe Today’s Topics Astronomy - Planets around other Stars Textbook: Ch. 4.4 - see also Lab 4 on “Gravity & Extrasolar Planets” 4
Image of page 4
NATURE of the Universe Stars, Disks & Planets Astronomy - Planets around other Stars More than 2,500 years ago, Greek philosophers speculated that many worlds might exist. In the 1,700s, Immanuel Kant and Pierre-Simon Laplace formed our modern view that the planets of the solar system formed in a disk . Democritus Epicurus Kant Laplace 5 See, e.g., http://www.ucolick.org/~bryden/ for more details on current planet formation theory
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
NATURE of the Universe Stars, Disks & Planets Astronomy - Planets around other Stars The Orion nebula houses many young stars with disks. Let’s take an imaginary flight through the Orion nebula ... 6 The volume visualization movie of Orion can be found at http://www.vislab.uq.edu.au/ research/vistools/index.html
Image of page 6
NATURE of the Universe Stars, Disks & Planets Astronomy - Planets around other Stars Mercury transit - the view in white light (photosphere of the Sun) and in the light of the red hydrogen line (chromosphere of the Sun) Challenges of direct detections of planets around stars 7 Notice how tiny Mercury is compared to the Sun!
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
NATURE of the Universe Stars, Disks & Planets Astronomy - Planets around other Stars The angle between the Sun and Jupiter as seen from α Centauri is 4 arcsec . This corresponds to the angle between the two headlights of a car at a distance of 75 km (50 miles). 8
Image of page 8
NATURE of the Universe Stars, Disks & Planets Astronomy - Planets around other Stars A further complication .... (or can you see Jupiter during daylight?) Firefly Car headlights In the visual the Sun is 1 billion times brighter than Jupiter. This is comparable to the contrast between car headlights and the glow from a firefly.
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern