Astronomy and Planetary Science Lecture Notes

These flashcards cover key concepts and details from lecture notes on astronomy and planetary science, focusing on exoplanets, the Kepler mission, celestial mechanics, and specific astronomical phenomena.

What does the depth of a transit depend on?

The size of the exoplanet relative to the size of the star.

What can a study of an exoplanet's atmospheric composition involve?

Comparing spectra of the star taken during and not during the transit.

What significant data did the Kepler Space Telescope gather?

Detected about 5000 transits, with 90% likely exoplanets and over 4000 confirmed.

What did the Kepler mission reveal about Sun-like stars?

1 in 5 has a roughly Earth-sized planet in the habitable zone.

What constitutes a 'Goldilocks planet'?

A planet in the habitable zone where liquid water could exist.

How common are small planets compared to large planets in our galaxy?

Small planets are more common than large planets.

What does the term 'center of mass' refer to in astronomy?

The balance point around which a star and planet orbit.

When was the first exoplanet discovered?

October 1995, orbiting the star 51 Pegasi.

What are 'Hot Jupiters'?

Big exoplanets with very small orbits, likely spiraling inward after formation.

Why do planets generally not twinkle as much as stars?

Planets have disks of light rather than point-like sources, averaging out brightness fluctuations.

What happens during a total lunar eclipse?

The Earth passes between the Sun and the Moon, causing the Moon to appear reddish.

What are meteoroids?

Small bodies (diameter < 1 m) orbiting the Sun, often coming from the asteroid belt.

What is the definition of a planet according to the August 2006 criteria?

A body that primarily orbits the Sun, is spherical due to its gravity, and has cleared its neighborhood of other objects.

What indicates a collision with an asteroid larger than 10 km?

It could likely end human civilization and create a massive explosion.

What unique phenomena were documented when Comet Shoemaker-Levy 9 collided with Jupiter?

Chunks released energetic impacts, up to 6 million megatons TNT.

What does Doppler Wobble refer to in exoplanet discovery?

Periodic motion of a star's radial velocity caused by an orbiting planet.

What is a primary function of telescopes in astronomy?

To collect more light to observe distant stars and celestial objects.

How far is the nearest star, Proxima Centauri?

About 4.2 light-years away.

What does the term 'light year' mean?

The distance that light travels in one year, approximately 10 trillion kilometers.

What is chromatic aberration?

A distortion in refracting telescopes where glass bends different wavelengths of light by different amounts.

What does the depth of a transit depend on?

The size of the exoplanet relative to the size of the star.

What can a study of an exoplanet's atmospheric composition involve?

Comparing spectra of the star taken during and not during the transit.

What significant data did the Kepler Space Telescope gather?

Detected about 5000 transits, with 90% likely exoplanets and over 4000 confirmed.

What did the Kepler mission reveal about Sun-like stars?

1 in 5 has a roughly Earth-sized planet in the habitable zone.

What constitutes a 'Goldilocks planet'?

A planet in the habitable zone where liquid water could exist.

How common are small planets compared to large planets in our galaxy?

Small planets are more common than large planets.

What does the term 'center of mass' refer to in astronomy?

The balance point around which a star and planet orbit.

When was the first exoplanet discovered?

October 1995, orbiting the star 51 Pegasi.

What are 'Hot Jupiters'?

Big exoplanets with very small orbits, likely spiraling inward after formation.

Why do planets generally not twinkle as much as stars?

Planets have disks of light rather than point-like sources, averaging out brightness fluctuations.

What happens during a total lunar eclipse?

The Earth passes between the Sun and the Moon, causing the Moon to appear reddish.

What are meteoroids?

Small bodies (diameter < 1 m) orbiting the Sun, often coming from the asteroid belt.

What is the definition of a planet according to the August 2006 criteria?

A body that primarily orbits the Sun, is spherical due to its gravity, and has cleared its neighborhood of other objects.

What indicates a collision with an asteroid larger than 10 km?

It could likely end human civilization and create a massive explosion.

What unique phenomena were documented when Comet Shoemaker-Levy 9 collided with Jupiter?

Chunks released energetic impacts, up to 6 million megatons TNT.

What does Doppler Wobble refer to in exoplanet discovery?

Periodic motion of a star's radial velocity caused by an orbiting planet.

What is a primary function of telescopes in astronomy?

To collect more light to observe distant stars and celestial objects.

How far is the nearest star, Proxima Centauri?

About 4.2 light-years away.

What does the term 'light year' mean?

The distance that light travels in one year, approximately 10 trillion kilometers.

What is chromatic aberration?

A distortion in refracting telescopes where glass bends different wavelengths of light by different amounts.

How does gravitational microlensing detect exoplanets?

By observing the temporary brightening of a background star as a foreground star and its planet pass in front of it.

What is direct imaging for exoplanets?

Directly observing light from an exoplanet, usually requiring large telescopes and adaptive optics.

What are comets mostly made of?

Ice, dust, and rocky material, often described as 'dirty snowballs'.

What are the main visible parts of a typical comet?

The nucleus, coma, and a tail (or tails).

Where is the main asteroid belt located?

Between the orbits of Mars and Jupiter.

What is the distinction between a meteor and a meteorite?

A meteor is a 'shooting star' in Earth's atmosphere; a meteorite is a piece that lands on Earth's surface.

What defines a dwarf planet, and what is an example?

A celestial body that orbits the Sun, is massive enough to be spherical, but has not cleared its orbital neighborhood. Pluto is a well-known example.

How does a reflecting telescope collect light?

Using mirrors to gather and focus light.

What is an advantage of reflecting telescopes over refracting telescopes?

They can be built much larger and avoid chromatic aberration because mirrors don't refract light.

What does the depth of a transit depend on?

The size of the exoplanet relative to the size of the star.

What can a study of an exoplanet's atmospheric composition involve?

Comparing spectra of the star taken during and not during the transit.

What significant data did the Kepler Space Telescope gather?

Detected about 5000 transits, with 90% likely exoplanets and over 4000 confirmed.

What did the Kepler mission reveal about Sun-like stars?

1 in 5 has a roughly Earth-sized planet in the habitable zone.

What constitutes a 'Goldilocks planet'?

A planet in the habitable zone where liquid water could exist.

How common are small planets compared to large planets in our galaxy?

Small planets are more common than large planets.

What does the term 'center of mass' refer to in astronomy?

The balance point around which a star and planet orbit.

When was the first exoplanet discovered?

October 1995, orbiting the star 51 Pegasi.

What are 'Hot Jupiters'?

Big exoplanets with very small orbits, likely spiraling inward after formation.

Why do planets generally not twinkle as much as stars?

Planets have disks of light rather than point-like sources, averaging out brightness fluctuations.

What happens during a total lunar eclipse?

The Earth passes between the Sun and the Moon, causing the Moon to appear reddish.

What are meteoroids?

Small bodies (diameter < 1 m) orbiting the Sun, often coming from the asteroid belt.

What is the definition of a planet according to the August 2006 criteria?

A body that primarily orbits the Sun, is spherical due to its gravity, and has cleared its neighborhood of other objects.

What indicates a collision with an asteroid larger than 10 km?

It could likely end human civilization and create a massive explosion.

What unique phenomena were documented when Comet Shoemaker-Levy 9 collided with Jupiter?

Chunks released energetic impacts, up to 6 million megatons TNT.

What does Doppler Wobble refer to in exoplanet discovery?

Periodic motion of a star's radial velocity caused by an orbiting planet.

What is a primary function of telescopes in astronomy?

To collect more light to observe distant stars and celestial objects.

How far is the nearest star, Proxima Centauri?

About 4.2 light-years away.

What does the term 'light year' mean?

The distance that light travels in one year, approximately 10 trillion kilometers.

What is chromatic aberration?

A distortion in refracting telescopes where glass bends different wavelengths of light by different amounts.

How does gravitational microlensing detect exoplanets?

By observing the temporary brightening of a background star as a foreground star and its planet pass in front of it.

What is direct imaging for exoplanets?

Directly observing light from an exoplanet, usually requiring large telescopes and adaptive optics.

What are comets mostly made of?

Ice, dust, and rocky material, often described as 'dirty snowballs'.

What are the main visible parts of a typical comet?

The nucleus, coma, and a tail (or tails).

Where is the main asteroid belt located?

Between the orbits of Mars and Jupiter.

What is the distinction between a meteor and a meteorite?

A meteor is a 'shooting star' in Earth's atmosphere; a meteorite is a piece that lands on Earth's surface.

What defines a dwarf planet, and what is an example?

A celestial body that orbits the Sun, is massive enough to be spherical, but has not cleared its orbital neighborhood. Pluto is a well-known example.

How does a reflecting telescope collect light?

Using mirrors to gather and focus light.

What is an advantage of reflecting telescopes over refracting telescopes?

They can be built much larger and avoid chromatic aberration because mirrors don't refract light.

What is the formula for calculating the depth of a planetary transit?

ext{Transit Depth} = rac{L{planet}}{L{star}} = rac{ ext{Area}{planet}}{ ext{Area}{star}} = rac{\pi Rp^2}{\pi Rs^2} = \left(\frac{Rp}{Rs}\right)^2, where Rp is the radius of the planet and Rs is the radius of the star.

How is a light-year calculated given the speed of light and time?

ext{Distance} = ext{Speed} \times ext{Time}. A light-year is approximately (3 \times 10^8 \text{ m/s}) \times (31,536,000 \text{ s}) \approx 9.46 \times 10^{15} \text{ meters}, or 9.46 \times 10^{12} \text{ km}.

What is the relationship between the period (P) of a star's wobble and the orbital period of the exoplanet?

The period of the star's radial velocity wobble (P{star}) is equal to the orbital period of the exoplanet (P{exoplanet}), i.e., P{star} = P{exoplanet}.

What is a simplified form of Kepler's Third Law for a planet orbiting a star (where the planet's mass is much smaller than the star's mass)?

P^2 \propto a^3, where P is the orbital period and a is the semi-major axis (average orbital distance). This implies that \frac{P^2}{a^3} = \text{constant} for all objects orbiting the same star.

What does the depth of a transit depend on?

The size of the exoplanet relative to the size of the star.

What can a study of an exoplanet's atmospheric composition involve?

Comparing spectra of the star taken during and not during the transit.

What significant data did the Kepler Space Telescope gather?

Detected about 5000 transits, with 90% likely exoplanets and over 4000 confirmed.

What did the Kepler mission reveal about Sun-like stars?

1 in 5 has a roughly Earth-sized planet in the habitable zone.

What constitutes a 'Goldilocks planet'?

A planet in the habitable zone where liquid water could exist.

How common are small planets compared to large planets in our galaxy?

Small planets are more common than large planets.

What does the term 'center of mass' refer to in astronomy?

The balance point around which a star and planet orbit.

When was the first exoplanet discovered?

October 1995, orbiting the star 51 Pegasi.

What are 'Hot Jupiters'?

Big exoplanets with very small orbits, likely spiraling inward after formation.

Why do planets generally not twinkle as much as stars?

Planets have disks of light rather than point-like sources, averaging out brightness fluctuations.

What happens during a total lunar eclipse?

The Earth passes between the Sun and the Moon, causing the Moon to appear reddish.

What are meteoroids?

Small bodies (diameter < 1 m) orbiting the Sun, often coming from the asteroid belt.

What is the definition of a planet according to the August 2006 criteria?

A body that primarily orbits the Sun, is spherical due to its gravity, and has cleared its neighborhood of other objects.

What indicates a collision with an asteroid larger than 10 km?

It could likely end human civilization and create a massive explosion.

What unique phenomena were documented when Comet Shoemaker-Levy 9 collided with Jupiter?

Chunks released energetic impacts, up to 6 million megatons TNT.

What does Doppler Wobble refer to in exoplanet discovery?

Periodic motion of a star's radial velocity caused by an orbiting planet.

What is a primary function of telescopes in astronomy?

To collect more light to observe distant stars and celestial objects.

How far is the nearest star, Proxima Centauri?

About 4.2 light-years away.