Exam 4 Flashcards
Who discovered the first periodic comet?
Edmond Halley
Two men independently discovered comet hale-bopp. Who was the astronomer and who was the amateur astronomer with a borrowed telescope?
Alan Hale was the astronomer
Thomas Bopp was the amateur astronomer
How long was comet Hale-Bopp visible?
18 months
How many comets have been visited and imaged by spacecraft as discussed in class?
6? 22?
Which comet was visible during this semester?
Comet Tsuchinshan-ATLAS
Which mission returned a sample of comet dust to Earth?
Stardust
which mission had both an impactor and a flyby?
Comet Temple 1 & Deep impact
Which mission followed a comet in its orbit to see how it changed in time?
Rosetta
What is the diameter of the nucleus of a typical comet?
10-20 km
Which of a comet’s tails is made by the solar wind?
Gas Tail
Which of a comet’s tail is made by radiation pressure?
Dust Tail
Which of a comet’s tail is curved and why?
Dust Tail
Affected by gravity (Kepler’s Law)
In which direction do comet tails point?
Away from the sun
what do comets have to do with meteor showers?
A meteor shower can happen when Earth passes through the trail of a comet
When will we see another great comet?
a long time
How long are the periods of short period comets?
Up to 200 years
How long until comet Hale-Bopp will be back again?
2,400 years
Around the year 4385
Are great comets usually short period or long period comets?
They can be either but usually long period
Given the provisional name of a comet, identify the type of comet and the year and month it was discovered
p/: periodic short term
c/: non periodic long term
D/: periodic comet that broke up or was lost
a/: wrongly designated as a comet
i/: interstellar object
Year discovered, letter indicating 1/2 month of discovery
Starts with January as AB and goes to December as XY and skips “i”
How many interstellar objects have been discovered? Name them
2
Oumuamua and 2I/Borisov
Where do short period comets come from?
Kuiper Belt
Where to do long period comets come from?
Oort Cloud
Where is the Kuiper Belt the most dense?
Most dense 40 to 48 AU
How many known Kuiper Belt objects are there?
1,000
What is the total mass of the Kuiper Belt compared to the Earth’s
10% of the Earths
What is the orbital resonance between Neptune and Plutions?
3:2
What part of the Kuiper Belt is the principal source of comets?
Scattered disc
When was pluto discovered?
1930
How does Pluto’s diameter and mass compare to Earth’s
Diameter: 1/5
Mass: 0.002 x
When were transits of Pluto and Charon last visible from Earth? When will the next transit be?
Last visible 1985-1990
Next transits: 2103-2117
How long does it take pluto to orbit the Sun?
248 earth years
Which mission did a flyby of Pluto? Whose ashes were onboard this mission?
New horizons with Clyde Tombaugh ashes
When was the second Kuiper Belt object discovered?
1992
How many dwarf planets in the Kuiper Belt do we presently have? Name them
5
- Pluto
- Haumea
- Makemake
- Eris
- GongGong
Which dwarf planet is the most massive?
Eris
Why does Haumea have such an unusual shape?
Ellipsoid shape, equators twice the radius as poles
What is the name of the Kuiper Belt object that is the farthest object visited by spacecraft?
Arrokoth
What is the shape of the Inner Oort Cloud? What dwarf planet is found here?
Donut Shaped
Sedna
What is the Shape of the Outer Oort Cloud?
Spherical shell
What can change the orbit of a comet?
- Interstellar gas cloud
- Supernova shock wave
- Passing Star
- Dense part of the milky way
What is the distance from the Earth to the Sun in AU, miles and Sun diameters?
1 AU or 9.296e+7 miles
Sun diameters: 864,000 miles
How does the Sun’s diameter compare to the Earth’s Diameter and Mass?
Diameter: 109 x
Mass: 300,000 x
How does the Sun’s mass compare to Jupiter’s?
1,000 x
What percent of the Sun’s mass is composed of elements heavier than helium?
2%
What is the average rotation period of the Sun?
27 days
What is the surface temperature of the Sun?
10,000 degrees F
What is the power output of the Sun?
4 x 10^26 watts
400 yota watts
What is the source of the Sun’s energy?
Nuclear fusion
What is the temperature of the core of the Sun?
27 million degrees F
What percent of the Sun’s total m ass has been converted into energy during the 5 billion years that the Sun has been shinning?
0.035%
How long does it take for energy to get from the core of the Sun to its surface?
tens of thousands to millions of years
What kind of particles are used to study the Sun’s core?
Solar neutrino
What is the solar neutrino problem?
Only 1/3 of expected neutrinos were detected
What is the solution to the solar neutrino problem?
Neutrinos comes in three flavors and change their identities. Look for the other ones
Put the following layers of the Sun in order from the center of the Sun to its outer atmosphere: chromosphere, convective zone, core, corona, photosphere, radiative zone
- Core
- Radiative zone
- Convective zone
- Photosphere
- Chromosphere
- Corona
What causes sunspots to be cooler?
Convection is hindered and there is localized cooling
What is the period of the solar cycle from maximum solar activity to maximum solar activity?
Around 11 years
What ceases the solar cycle?
Sun’s magnetic activity
In what layer of the Sun’s atmosphere are spicules found?
Chromosphere
What part of the Sun’s atmosphere is the hottest?
Corona
What are solar prominence?
huge plumes of glowing gas
What are solar flares?
Brief but bright eruption of gas
What are coronal mass ejection?
enormous bubbles of hot gas burst from the corona out into space
Which lasts longer a solar prominence or a solar flare? Which did we see when we looked at the Sun?
Solar prominence
What is the solar wind mostly composed of?
Hydrogen and helium
Which mission made three solar scans at all latitudes?
Ulysses
Which mission was able to see the whole Sun?
STEREO
What mission has a set of postage stamps?
SDO
Which mission is studying the Sun up close?
Parker solar probe
Are planets common around other stars? How common?
Yes
If the sun were the size of a grapefruit and was located in California, where would the nearest star be?
Florida
Why is it so difficult to directly image an exoplanet?
Its like sitting in California and taking a picture of a firefly b a street light in Florida
Why is the James Webb Space Telescope a good choice for directly imaging exoplanets?
Because it is not affected by earth’s atmosphere
What are the 3 main methods for detecting exoplanets?
- Radial velocity
- Astrometry
- Transit
Which method works best for close stars with distant massive planets?
Astrometric method
What method works best for massive planets that are close to their stars?
Radial Velocity method
Which method likely only works for 1% of stars?
Transits and Eclipses
How many stars did the Kepler Mission watch for transits in the original part of its mission?
150,00 stars ever 30 minutes
Which method has been used to discover the most exoplanets?
Transit method
Over 70%
Which method can be used to determine the orbital period of exoplanets?
Transit method
Which method can be used to determine the eccentricity of exoplanets?
Radial velocity method
Which method can be used to determine the size of exoplanets?
Transit method
What two method are used to determine the density of exoplanets?
Transit Method and Radial Velocity Method
How many confirmed exoplanets have been discovered to date?
5,612
What percent of confirmed exoplanets are terrestrials?
4%
What kind of planet was the first exoplanet found around a Sun like Star?
Hot Jupiter
How many planets have been discovered orbiting TRAPPIST-1?
7 known planets
HAT-P-32 b has a density similar to?
Styrofoam
What method was used to find OGLE-2005-BLG-390L b?
Gravitational Lensing Technique
What kind of rain falls on the nightside of WASP-76 b?
Iron Rain
