## Astronomy C

boomvroomshroom
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### Astronomy C

Question marathon for Astronomy.

boomvroomshroom
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### Re: Astronomy C

Starting question: Pretend you are an alien observing our solar system. What is the transit probability for Jupiter, our largest planet?

Techsam
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### Re: Astronomy C

Thanks for starting the Astronomy Question Marathon boomvroomshroom!

Here is what I believe to be the solution to the question you asked:

To calculate the geometric transit probability of a planet you use the equation: Probability = d*/(2a) where d* is the stellar diameter (=0.0093 AU for the Sun) and a is the planet's orbital radius.

The probability for Jupiter will therefore be = .0093/(5.2*2) = .0894%
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Transit Probablity

boomvroomshroom
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### Re: Astronomy C

Techsam
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### Re: Astronomy C

Given the black-body radiation curve of Star X, what is the temperature of Star X in Kelvin?
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Black-body Curve for Star X
Blackbody Curve.png (7.21 KiB) Viewed 3788 times

finagle29
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### Re: Astronomy C

Using Wien's Displacement Law,  $T_{eff}=\frac{b}{\lambda_{max}}=\frac{2.989\times 10^{-3}\,\rm{mK}}{0.4\,\rm{\mu m}}=7245\, \rm{K}$
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Techsam
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### Re: Astronomy C

Correct! Great use of Latex too, I'm impressed

boomvroomshroom
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### Re: Astronomy C

Define a hot Jupiter and a super earth. How are they same/different from those in our solar system?

Techsam
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### Re: Astronomy C

Define a hot Jupiter and a super earth. How are they same/different from those in our solar system?
A hot jupiter is a massive gas planet, much like jupiter, but its orbit has drifted closer to the transiting star and has heated up. (Massive planets like Jupiter can also generate their own heat due to their gravitational attracting). Super earths refer to planets that resemble earth, but at much more massive probably around 2-5 times as massive. This planets orbit in the habitable zones, and are assumed to be rocky and contain water on the surface. Large gaseous planets in out solar system (Saturn, Jupiter, Uranus, and Neptune) are found in the outer regions, and the rocky planets (Mercury, Venus, Earth, Mars) are found to orbit in the inner regions. Hot Jupiters differ because they orbit much closer to their parent star, which made astronomers rethink the solar system formations.

boomvroomshroom
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### Re: Astronomy C

Techsam wrote:
A hot jupiter is a massive gas planet, much like jupiter, but its orbit has drifted closer to the transiting star and has heated up. (Massive planets like Jupiter can also generate their own heat due to their gravitational attracting). Super earths refer to planets that resemble earth, but at much more massive probably around 2-5 times as massive. This planets orbit in the habitable zones, and are assumed to be rocky and contain water on the surface. Large gaseous planets in out solar system (Saturn, Jupiter, Uranus, and Neptune) are found in the outer regions, and the rocky planets (Mercury, Venus, Earth, Mars) are found to orbit in the inner regions. Hot Jupiters differ because they orbit much closer to their parent star, which made astronomers rethink the solar system formations.