Exploring the Universe Final Exam: Exoplanets and Binary Stars

extra solar planet/exoplanet

A planet that orbits a star outside our solar system.

direct imaging method

A technique used to directly capture images of exoplanets by blocking out the light from their parent stars.

center of mass of a star-planet system

The point around which both the star and the planet orbit.

coronagraph

An instrument used to block out the light from a star, allowing for the observation of objects near it.

star shade

A device designed to block the light from a star to facilitate the observation of exoplanets.

red shifted star

A star whose light is shifted towards the red end of the spectrum, indicating it is moving away from the observer.

blue shifted star

A star whose light is shifted towards the blue end of the spectrum, indicating it is moving towards the observer.

wobble method

A technique for detecting exoplanets by observing the gravitational effects they have on their parent stars, causing the stars to wobble.

transit method

A method of detecting exoplanets by observing the dimming of a star's light as a planet passes in front of it.

visual binary

A binary star system in which the two stars can be individually resolved through direct observation.

spectroscopic binary

A binary star system in which the presence of two stars is inferred from their spectral lines.

eclipsing binary

A binary star system in which one star passes in front of the other, causing periodic dimming.

binary stars

Two stars that are gravitationally bound to each other and orbit a common center of mass.

Hubble's law

The observation that the farther away a galaxy is, the faster it is moving away from us.

Hubble's constant

The rate of expansion of the universe, typically expressed in kilometers per second per megaparsec.

time taken by 2 stars to complete one orbit

Equal for both stars in a binary system.

detection of planets using wobble method

Requires the planet to be in an edge-on star system.

relationship between blueshift and redshift with binary stars

As one star moves closer and becomes blueshifted, the other moves away and becomes redshifted

how we know the universe is expanding

Red shift of distant galaxies.

factor that makes black holes and their event horizons larger

Higher mass makes a black hole and its event horizon larger.

likelihood of planets forming around a star

Most stars form planets around them, so exoplanets are common.

relationship between exoplanet size and ease of detection with the transit method

Larger planets are easier to detect with the transit method.

orientation of a planetary system relative to Earth that can be detected by transit method and wobble method

Edge-on.

type of planet easiest to detect with direct imaging

Super-Jupiter.