- Attachment:
- One planet in particular has been the most studied and the first discovered in 2009. Now, after early 3 years of study, confirmation has been made with 3 transits of the planet about the star. The planet’s orbit is 290 days. We witness the transit with a dip in the star’s brightness as the planet passes in front of it in our line of sight.. We have witnessed 3 transits: 3 * 290 days = 870 days = 2.4 years.
- The planet is named Kepler 22b and its solar system is 600 lightyears away. The star that is hosting this planet is spectral type “G”, which means it is very similar to our Sun that has a temperature of 6,000 to 5,000 Kelvin, greenish yellow color.
- Stars are classified by letters: “O”, “B”, “A”, “F”, “G”, “K”, “M”
-------------------- “ Oh be a fine girl kiss me”
- Here are the classifications be temperature, lifespan, peak wavelength, and example stars:
-----Spectral Type ----- Temperature ----Lifetime --------- Wavelength --- Example
------------------------------Kelvin---------million years ---- nanometers --------------
--------- O ------------ 35,000-30,000 ------ 3 -------------<97 -------- Orion’s Belt.
--------- B ------------ 30,000-10,000 ------ 15 ----------- to 290 -------- Rigel
--------- A ------------ 10,000-7,500 ------- 500 -----------to 390 -------- Sirius
--------- F ------------ 7,500-6,000 --------- 3,00------------ to 480 -------- Polaris
--------- G ------------ 6,000-5,000 --------- 10,000 --------- to 580 -------- Sun
--------- K ------------ 5,000-3,5000 ------- 15,000-----------to 830-------- Arcturus
--------- M ------------ < -3,500 --------- 200,000 -------- > 830 -------- Betelgeuse
- Planet Kepler 22b is 2.4 times he diameter f Earth, about ½ the size of Neptune. It could be anywhere from 10 to 35 Earth masses. Knowing its mass would help us decide if it is mostly ocean with a small rocky core, or a gaseous planet more like Neptune.
- The planet’s orbit is about 15% less than Earth’s orbit about the Sun. However, the star it is orbiting is 25% less luminosity than our Sun. This combination should bring the moderate temperatures to the planet to allow liquid water. Without an atmosphere the temperature would average -11C. But, with an atmosphere and he greenhouse effect that comes with it the temperature should average + 22C , or, 72 degrees Fahrenheit. Sounds pretty nice.
- There are 48 other planet candidates out of the 1,094 discovered by the Kepler Space Telescope that are in similar situations. But, more data needs to be collected on these candidates before good estimates on habitability can be made.
- The Kepler Space Telescope is starring at on spot in the sky. The singe field of view contains over 150,000 stars that are being recorded. If a star’s brightness dips in repeated fashion, it might be caused by a planet in transit in front of the star from our point of view.
- The total number of planet candidates discovered by various other telescope and methods total 2,236 candidates. The Doppler shift of the star is another method astronomers use to identify stars with planets in orbit. The sizes of the 2,236 candidates are:
----------------- 207 are Earth-size
----------------- 680 are super-Earth-size
----------------- 1,181 are Neptune - size
---------------- 203 are Jupiter-size
--------------- 55 are larger than Jupiter.
- Of these candidates 48 are possible life habitable planets. All need further study, but Kepler 22b has the best confirmed data so far.
- To make an estimate of the mass of the planet we can assume it has the same density as the Earth, 5,500 kilograms / meter^3. We measure the radius of Kepler 22b to be about 15,000 kilometers.
-------------- Volume = 4/3 *pi* radius^3
-------------- Volume = 4/3 *(3.14)* (1.5*10^4^3
-------------- Volume = 14 * 10*12 kilometers^3
------------- Density = Mass // Volume
------------ Mass = (5.5*10^3) kg/m^3 * ( 14*10^21) m^3
------------- Mass = 78*20^24 kilograms
- The mass of the Earth = 5.97*10^24 kilograms
- Therefore, an estimate fro the mass of Kepler 22b is:
------------------------ Kepler 22b = 13 Earths
- If you were playing baseball on Planet Kepler22b, how much would the batter weigh and how big would the baseball diamond be?
- This all has to do with the force of gravity on Planet Kepler22b. On Earth the acceleration of gravity is 9.8 meters / second^2. ( 32 feet per second per second).
- The acceleration of gravity, “g”, is directly proportional to the mass , “M” and inversely proportional to the square of the radius , “r^2”.
------------------------- g = G * M // r^2
-------------------------- G = The Gravitational Constant which is supposed to be the same everywhere in the Universe
------------------------- G = 6.67 * 10^-11 m^3 //(kg*sec^2)
------------------------- g = (6.67 * 10^-11) * (78*10^24) // (1.5*10^7)^2
-------------------------- g = 23 m/sec^2
---------------------- g = 23 m/sec^2 // 9.8 m/sec^2
- Gravity is 2.4 times greater on Planet Kepler 22b. The batter weighs 150 pounds on Earth. She would weigh 2.4 * 150 = 354 pounds at home plate on Planet Kepler22b.
- The Home Run fence is 325 feet away from Home Plate on Earth. The fence would be 325//2.4 = 147 feet away on Kepler’s base ball diamond. However, to run the bases she would only have to go 90 // 2.4 = 38 feet between bases. What would the approximate batting average on the Planet Kepler22b? ----------------- Just kidding!
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707-536-3272, Wednesday, December 14, 2011
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