Exoplanets

hot jupiter

A gas giant exoplanet located much closer to its star than expected based on the solar nebula model for planet formation

A planet called a super-earth could have a mass anywhere from 2 to 10times Earth's mass

A planet called a super-earth could have a mass anywhere from 2 to 10times Earth's mass

All the true statements comparing brown dwarfs to planets. · The least massive brown dwarfs are about 13 times more massive than Jupiter. · Although they cannot sustain the reactions that power regular stars, unlike gas giants, some fusion can occur in brown dwarfs.

All the true statements comparing brown dwarfs to planets. · The least massive brown dwarfs are about 13 times more massive than Jupiter. · Although they cannot sustain the reactions that power regular stars, unlike gas giants, some fusion can occur in brown dwarfs.

An exoplanet with between 2 and 10 times Earth's mass and a radius from 1.25 to 2 times Earth's is called (an) super- earth.

An exoplanet with between 2 and 10 times Earth's mass and a radius from 1.25 to 2 times Earth's is called (an) super- earth.

Astronomers are detecting some exoplanets and measuring their sizes as they transit in front of their star, dimming its light.

Astronomers are detecting some exoplanets and measuring their sizes as they transit in front of their star, dimming its light.

Astronomers have detected material around some young stars consistent with the early stages of solar nebula theory.

Astronomers have detected material around some young stars consistent with the early stages of solar nebula theory.

By measuring the Doppler shift of stars, it is possible to detect a "wobble" due to the gravitational pull of orbiting exoplanets.

By measuring the Doppler shift of stars, it is possible to detect a "wobble" due to the gravitational pull of orbiting exoplanets.

Detecting a planet by observing the parent star's "wobble" actually shifting the position of the star on the sky is called the ___astrometric__ method.

Detecting a planet by observing the parent star's "wobble" actually shifting the position of the star on the sky is called the ___astrometric__ method.

Effects that a massive planet in a very elliptical orbit might have on its system. · It could disturb the orbits of the other planets. · Planets may be ejected from the system (reason: Reason: Ejection can result if a planet's orbit is disrupted). · Planets may collide with the parent star (Reason: A disrupted orbit might end up passing too close to the star).

Effects that a massive planet in a very elliptical orbit might have on its system. · It could disturb the orbits of the other planets. · Planets may be ejected from the system (reason: Reason: Ejection can result if a planet's orbit is disrupted). · Planets may collide with the parent star (Reason: A disrupted orbit might end up passing too close to the star).

Exoplanets have also been detected by microlensing of background stars.

Exoplanets have also been detected by microlensing of background stars.

Few exoplanets have been images directly because of their small separation from and dimness relative to the star.

Few exoplanets have been images directly because of their small separation from and dimness relative to the star.

How do we use the Doppler shift to find exoplanets? · We measure changes in the wavelength of the star's light resulting from its wobble in response to the orbiting planet (reason: this is called the radial velocity method).

How do we use the Doppler shift to find exoplanets? · We measure changes in the wavelength of the star's light resulting from its wobble in response to the orbiting planet (reason: this is called the radial velocity method).

In the Solar System, only terrestrial planets are found inside the frost line around 4 AU. How is it that gas giants orbit inside the frost line of other stars? · These giants formed far from their stars and migrated in (reason: Gas giants cannot form or survive very close to stars. Gravitational interactions among the planets can cause their orbits to change. Some models predict some stars might "eat" gas giants that get too close!)

In the Solar System, only terrestrial planets are found inside the frost line around 4 AU. How is it that gas giants orbit inside the frost line of other stars? · These giants formed far from their stars and migrated in (reason: Gas giants cannot form or survive very close to stars. Gravitational interactions among the planets can cause their orbits to change. Some models predict some stars might "eat" gas giants that get too close!)

Many of the massive exoplanets detected so for have very ellipticalorbits. This could lead to disruption of the orbits of smaller planets in these systems. (Reason: During the part of the orbit close to the star, the large planet would likely distrupt terrestrial planets' orbits.

Many of the massive exoplanets detected so for have very ellipticalorbits. This could lead to disruption of the orbits of smaller planets in these systems. (Reason: During the part of the orbit close to the star, the large planet would likely distrupt terrestrial planets' orbits.

Match the systems below with the method that would be the most likely to find it. · Direct imaging - A Jupiter-mass planet 100 AU from the star. · Radial velocity - A Jupiter-mass planet 1 AU from the star. · Gravitational lensing - A super-Earth 5 AU from the star. · Transit method -- A super-Earth 0.2 AU from the star.

Match the systems below with the method that would be the most likely to find it. · Direct imaging - A Jupiter-mass planet 100 AU from the star. · Radial velocity - A Jupiter-mass planet 1 AU from the star. · Gravitational lensing - A super-Earth 5 AU from the star. · Transit method -- A super-Earth 0.2 AU from the star.

Most of the planets detected so far orbit closer to their star than in the Solar System, but the detection methods are biased.

Most of the planets detected so far orbit closer to their star than in the Solar System, but the detection methods are biased.

Quantity that is reliably and unambiguously found when using the Doppler shift method to discover exoplanets. The orbital period of the planet

Quantity that is reliably and unambiguously found when using the Doppler shift method to discover exoplanets. The orbital period of the planet

The most common size of exoplanets lies between the size of Earth and Neptune, so we have no examples in the Solar System.

The most common size of exoplanets lies between the size of Earth and Neptune, so we have no examples in the Solar System.

Thousands of exoplanets have been detected, many in multiple-planet systems.

Thousands of exoplanets have been detected, many in multiple-planet systems.

To use the transit method to discover an exoplanet, it is necessary thatthe planet passes between us and the star, blocking some light(Reason: Measuring how much light is blocked by the planet, for how long, and how often, allows us to find the radius of the planet, the period of the orbit, and the planet's mass.)

To use the transit method to discover an exoplanet, it is necessary thatthe planet passes between us and the star, blocking some light(Reason: Measuring how much light is blocked by the planet, for how long, and how often, allows us to find the radius of the planet, the period of the orbit, and the planet's mass.)

We have detected many exoplanets, but we do not have many images of these planets. What is most prevalent reason why not? · The exoplanets are much dimmer than the stars. This makes them hard to see (reason: the planets are hard to see in the glare of the stars).

We have detected many exoplanets, but we do not have many images of these planets. What is most prevalent reason why not? · The exoplanets are much dimmer than the stars. This makes them hard to see (reason: the planets are hard to see in the glare of the stars).

What properties of an exoplanet can be determined by observing the pattern of changing radial velocities of a star? · Mass (reason: note that we get a lower limit on the mass (the planet is at least so big), because the angle at which we see the orbit affects the calculation). · Orbital distance

What properties of an exoplanet can be determined by observing the pattern of changing radial velocities of a star? · Mass (reason: note that we get a lower limit on the mass (the planet is at least so big), because the angle at which we see the orbit affects the calculation). · Orbital distance

When studying exoplanets using the astrometric method, the more distant the exoplanet is from the parent star, the greater the shift in position on the sky, or "wobble" of the star. · True (Reason: Exoplanets at a greater orbital distance produce a larger wobble. However, it also takes longer for the pattern to repeat.)

When studying exoplanets using the astrometric method, the more distant the exoplanet is from the parent star, the greater the shift in position on the sky, or "wobble" of the star. · True (Reason: Exoplanets at a greater orbital distance produce a larger wobble. However, it also takes longer for the pattern to repeat.)

You discover a system of five exoplanets in which the order of planets from the star is gas giant, terrestrial, gas giant, terrestrial, gas giant. The phenomenon of planetary migration could explain how this came to be.

You discover a system of five exoplanets in which the order of planets from the star is gas giant, terrestrial, gas giant, terrestrial, gas giant. The phenomenon of planetary migration could explain how this came to be.

brown dwarf

a body intermediate between a star and a planet. A brown dwarf has a mass between about 0.017 and 0.08 solar masses—too low to fuse hydrogen in its core, but high enough to fuse deuterium as it contracts

super-earth

a category of exoplanet with a radius about 1.25 to 2 times Earth's radius

protoplanetary disk

a disk of material encircling a protostar or a newborn star.

radial velocity method

a means of detecting planets orbiting other stars by detecting the Doppler shift caused by the star's own reflect motion in response to the orbiting planet

transit method

a method for detecting planets orbiting other stars by detecting the slight dimming if the planet's orbit causes it to cross in front of the star.

exoplanet

a planet orbiting a star other than our Sun

microlensing method

a technique for detecting a planet orbiting a star by observing a small extra brightening as the gravitational field of the planet acts as a lens and focuses the light of a background star.

astrometric method

a technique for detecting a planet orbiting another star by observing the side to side "wobble" of the star on the sky caused by the pull of the orbiting planet.

· A more edge-on orientation (Reason: The closer to edge-on we see the system, the more directly the star moves toward and away from us as it wobbles, making the shifts easier to detect). · Larger mass exoplanet (Reason: A larger mass would increase the wobble of the parent star, making the shifts larger).

· A more edge-on orientation (Reason: The closer to edge-on we see the system, the more directly the star moves toward and away from us as it wobbles, making the shifts easier to detect). · Larger mass exoplanet (Reason: A larger mass would increase the wobble of the parent star, making the shifts larger).

· Exoplanet - A planet orbiting a star other than the Sun · Protoplanetary disk - The disk of gas and dust in which a star forms · Brown dwarf - A body that fuses some elements in its core but is not a star · Migrating planet - A planet whose orbit has changed

· Exoplanet - A planet orbiting a star other than the Sun · Protoplanetary disk - The disk of gas and dust in which a star forms · Brown dwarf - A body that fuses some elements in its core but is not a star · Migrating planet - A planet whose orbit has changed

· Massive -- makes Doppler shifts and astrometric shifts bigger. · Far from the parent star -- takes more time to detect motion and find the period. · Orbital plane is face-on (perpendicular to the line of sight) -- minimizes the Doppler effect and eliminates any chance of transits. · Large radius -- increases the probability and effect of transits.

· Massive -- makes Doppler shifts and astrometric shifts bigger. · Far from the parent star -- takes more time to detect motion and find the period. · Orbital plane is face-on (perpendicular to the line of sight) -- minimizes the Doppler effect and eliminates any chance of transits. · Large radius -- increases the probability and effect of transits.