ASTR1030 - FALL, 2008. LECTURE 33; PAGE 1
ASTR1030
http://lasp.colorado.edu/~ergun/
ASTR1030/
Next Observing: Wednesday, Dec. 3, 7:00 pm at SBO.
Today:
• Read Chapter S2-S3
• Exoplanets
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Lecture 33: Detection of Exoplanets in ASTR1030 - Fall, 2008 - Prof. Robert E. Ergun, Study notes of Astronomy
A set of lecture notes from the astr1030 course at the university of colorado boulder, taught in the fall of 2008. The notes cover the topic of exoplanet detection and discuss various methods used to discover planets outside our solar system, including radial velocity, transit, astrometry, imaging, gravitational micro-lensing, and orbital phase or timing. The document also includes examples of exoplanets detected using these methods.
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Download Lecture 33: Detection of Exoplanets in ASTR1030 - Fall, 2008 - Prof. Robert E. Ergun and more Study notes Astronomy in PDF only on Docsity!
ASTR
http://lasp.colorado.edu/~ergun/
ASTR1030/
Next Observing: Wednesday, Dec. 3, 7:00 pm at SBO.
Today: • Read Chapter S2-S3• Exoplanets
ASTR1030 - FALL, 2008. LECTURE 33; PAGE 2
Light
Doppler Shift
v - - c
λ
shift
λ
laboratory
- λ
laboratory
v
c
∆λλ
0
ASTR1030 - FALL, 2008. LECTURE 33; PAGE 4
Detecting Planets
Main Methods
•^
Astrometry
: Precise measurement a star's position. If one detects periodic
changes (wobbles) over time, the star may have a planet.
-^
Radial velocity or Doppler method
: Measurement of periodic variations in
a star’s speed. Doppler is by far the most productive technique used. Abovetwo: 303 exoplanets in 261 systems. 30 systems have multiple planets
•^
Transit
: If a planet crosses (or transits) in front of its star, then the star dims
by a small amount, depending on the relative size of the star and the planet.52 planets in 52 systems.
-^
Imaging
: Direct detection of light reflecting (or emitted if IR) from planet.
11 exoplanets in 9 systems
-^
Gravitational micro-lensing
: The gravitational field of a planet acts like a
lens, magnifying the light of a distant background star. 8 exoplanets in 7 sys-tems
•^
Orbital phase or Timing
: Periodic dimming of a star system’s light can be
caused by a planet’s orbital phase. 7 exoplanets in 4 systems
Note: a total of 329 exoplanets have been detected, many by multiple methods.
Extra-Solar Planets
Extra-Solar Planets
Extra-Solar Planets
Extra-Solar Planets
Extra-Solar Planets
Extra-Solar Planets
Extra-Solar Planets
Extra-Solar Planets
Imaging
Fomalhaut:
Spectral A, 2
M
S
Planet:
^3
M
J
, 115 AU, ~900 yr. orbit.
Imaging
HR
ASTR1030 - FALL, 2008. LECTURE 33; PAGE 20
Contrast Ratio
Let’s look at Jupiter and Sun from 20 ly away:Alternatively:The light from the Sun to Jupiter:Jupiter reflects ~1/2 from its disk:At 20 ly:
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