AST101: The Sun and its Neighbours - Class 20: Extra-solar Planets I

A set of flashcards summarizing key concepts from the AST101 lecture on extra-solar planets, including methods of detection, the characteristics of planets, and relevant astronomical distances.

What is the distance of Mercury from the Sun?

57,909,175 km

What astronomical unit (AU) distance is equivalent to Jupiter's distance from the Sun?

778,412,010 km (approximately 5.2 AU)

How do we measure distances in light years?

One light year is the distance light travels in one year.

What method is often used to find planets around other stars?

Direct Imaging.

What is the Doppler Effect in relation to light?

If the source is moving closer, the light shifts to a higher frequency (blueshift). If it's moving away, it shifts to a lower frequency (redshift).

What is the Radial Velocity Method?

It measures the motion of the star as it moves towards or away from us, revealing the presence of orbiting planets.

How can the mass of an exoplanet be estimated using the Radial Velocity Method?

The amount of motion observed in the star depends on the gravitational influence of the planet.

What are Hot Jupiters?

Gas giants that orbit very close to their stars, contrary to predictions from the nebular theory.

What is the Frost Line in planetary formation?

The distance in the solar nebula beyond which gas and ice could condense to form planets.

How far is the nearest star from our solar system?

Approximately 40.2 trillion kilometers or 4.247 light years.

What is one reason many exoplanets discovered are massive and close to their stars?

They are easier to detect using current observational techniques.

What was the first planet detected around a star?

51 Pegasi b.

What does the 'Center of Mass' imply in a star-planet system?

Both the star and planet orbit around their common center of mass.

Why is the James Webb Space Telescope particularly useful for exoplanet research?

It has excellent resolution and sensitivity, allowing for more detailed observations.

What happens if an orbit is viewed 'face-on' in terms of detecting exoplanets?

There will be no observable motion, making detection difficult.