Astronomy HW #10

Which two quantities need to be measured in order to determine the density of an extrasolar planet?

mass and radius

Statistical evidence suggests that about ________ percent of all stars have an approximately Earth-sized planet orbiting in a region around the star where water could exist as a liquid on the planet's surface.

20

What are the two primary methods by which planets have been found around other stars in our galaxy?I) Direct images in visible and infrared lightII) Indirectly by detecting the motion of the host starIII) Indirectly by measuring the drop in brightness of the host star when the planet crosses our line of sight

II and III

What could happen in planetary systems where the nebular gas is quickly disbursed?

Large ice-rich planetesimals would not be able to gather hydrogen and helium and become gas giants.

A transiting extrasolar planet is observed to block 1% of its host star's light. How does the size of this planet compare to the host star?

The planet's radius is 10% of the host star's radius.

How does the theory of planetary migration in disks possibly account for the highly eccentric orbits discovered for some extrasolar planets?

When migrating planets pass close enough for a gravitational encounter, one may be flung from the system while the other is shifted to a highly elliptical orbit.

Which of the following methods has led to the most confirmed discoveries of massive planets orbiting near their parent stars?

detecting the gravitational effect of an orbiting planet by looking for the Doppler shifts in the star's spectrum

The astrometric method of planet detection works best for

massive planets around nearby stars.

What is the most accurate way to measure the surface temperature of an extrasolar planet?

measure the drop in total infrared light when the planet passes behind the star Submit

The Doppler method can be used to measure the eccentricity of a planet's orbit by

measuring the asymmetries in the velocity curve.

The Doppler method can be used to estimate the semimajor axis of a planet's orbit by

measuring the time it takes for the star's line-of-sight velocity to cycle from peak to peak, and using Newton's version of Kepler's Third law.

The depth of the dip in a star's brightness due to the transit of a planet depends most directly on

the planet's size.

The reason that most extrasolar planets discovered by the Doppler method are found close to their parent stars is

the wavelength shift of the star's spectrum is larger.

The reason that most extrasolar planets discovered by the transit method are found close to their parent stars is

they transit more frequently and are more likely to be detected in the short time we have been searching for them. Submit