Final Pt 3

Question 1

The transit probability for an exoplanet depends on the _____ of the star, and planet, and the ___ between them

Answer 1

radius, distance

Question 2

The Kepler mission launched on march 7 in 2009, shows that _____% of visible stars are likely to have ___, possibly ___ planets similar in size to earth and located within the __ ___ of their parent stars. Kepler’s sole scientific instrument is a _____ that continually monitors the brightness of approximately _____ main sequence stars (transits)

Answer 2

20-50, small, rocky, habitable zone, photometer, 150,000

Question 3

The initial doppler discovery of many hot jupiters was a ____ sample

Answer 3

biased

Question 4

Comparing the average density of exoplanets to the density of planets in our solar system helps us to understand whether they are ___ or ___ in nature

Answer 4

rock, gaseous

Question 5

The first planetary system was found around the star ___ ___ in 1999 using the ____ method. This was both the first multiple-planet system to be discovered around a ______ star and the first multiple planet system known in a _____ system. Many others have been found since then. Many planetary systems have only ___ known planets but few have as many as ___. The ___ ___ ____ affect habitable zones.

Answer 5

upsilon andromedae, doppler, main sequence, multiple-star, 2, 5, stellar effective temperature

Question 6

Extrasolar planetary systems have objects that we didn’t see in the solar system. For example, the very close-in massive planets, ____ ____, or the very close-in smaller planets, ___ ____ to ____. ____ ____ also exist. We also find extrasolar planets in ____ with each other.

Answer 6

hot jupiters, hot neptunes, earths, super earths, resonance

Question 7

______ ___ was discovered in 1995 by radial velocity, It has a ____ day orbit, and a minimum mass ____x that of jupiter. It is _____°C and puffy. It was first thought to be ____ but now it is known it is numerous, and prompted theories of ___ ____

Answer 7

pegasi b, 4, 0.5, 950, anomalous, orbital migration

Question 8

The formation of hot jupiters at their current locations is ______. In models of core _____, both the available disk mass and the opening of __ ___ appear to preclude their growth.

Answer 8

unlikely, accretion, disk gaps

Question 9

Inward orbital migration is due to the ___ ____ with gas disks or _____ ____ which would naturally bring planets inward from their ___ ____.

Answer 9

gravitational interactions, planetesimal disks, formation sites

Question 10

When two planets _____ gravitationally, they end up on ___ orbits that are circularized by ______ at the periastron.

Answer 10

scatter, eccentric, tides

Question 11

The effect of tidal forces between a body in orbit around a central celestial object, whereby the eccentricity of the orbit is reduced over time so that it becomes less and less elliptical

Answer 11

tidal circularization

Question 12

Arise when two orbiting bodies exert a regular, periodic gravitational influence on each other as a result of simple numerical relationship between frequencies or periods

Answer 12

orbital resonances

Question 13

In orbital resonance, the ___ ___ between two bodies does not average to ____ over long time scales. this means the gravitational influences occur always at the same time, and are not ____. Exoplanet resonances must be ____.

Answer 13

repetitive force, zero, random, stable

Question 14

Gaps occurs where asteroids would have ___ ___ that are simple fractions of jupiter’s ___ year period, giving clues to ___ ____ ____

Answer 14

orbital periods, 12, mean motion resonance

Question 15

Current observations of transiting or ___ ____ systems typically do not allow definitive assignment to mean motion resonance. A common practice is to use ___ ___ ____ as a proxy for resonance. For example, the frequent occurrence of Kepler systems with ratios of ___ , ____, and ____, even if not strictly resonant orbits gives hints of information

Answer 15

radial velocity, orbital period ratios, 2:1, 3:1, 3:2

Question 16

Planets change orbits during their evolution with both their ___ ___ and _____ changing. For a sufficiently slow migration, the final state depends only on the ratio of the ___ times. For high migration rates, ___ ___ is suppressed. Depending on how the migration proceeds, planets can either be trapped or not in specific resonances

Answer 16

semimajor axis, eccentricity, e-folding, resonant capture

Question 17

You can get direct observable evidence of the planetary material (_____) outside of our solar system by observing ___ ___ ____. Cool white dwarves normally only show ___ or ___ lines

Answer 17

planetesimals, accreting white dwarves, H, He

Question 18

Unstable resonances have conjunctions where both planets are at their _____ to the star. This will cause their orbits to ____ ___

Answer 18

pericenters, drive away

Question 19

stable resonances occur when two planets are closest at both at their ______, or when one planet is at their ___ and one planet is at their ___ from the sun.

Answer 19

apocenter, apocenter, pericenter

Question 20

The derivation of ____ orbital elements which match the ____ for a multi-planet system, as derived from either ____ or ___ fitting does not guarantee that the resulting orbits are ___ over long periods of time. The best fitting solution might, for example, describe an unstable system which would swiftly disintegrate through ____ of one of the planets, or by causing two of the planets to _____.

Answer 20

keplerian, observables, kinetic, dynamic, stable, ejection, collide

Question 21

The two planet system ____ ___, with an age of ____ Gyr, has a best fit orbit that predicts that one of the two planets will either be ____ or ___ with the star within _____ years. In 2001, the star was found to contain an unusually high amount of _____. One or more of the planets may have fallen into the star, sometime after it passed through its early ____ stage. ___ ___ analysis hints at the presence of a third jovian planet.

Answer 21

HD 82943, 2.9, ejected, collide, 100,000, lithium-6, evolutionary, radial velocity

Question 22

the irregular behaviour that can occur in deterministic dynamic systems

Answer 22

chaos

Question 23

Upsilon andromedae is a ____ ___ system consisting of a star slightly more massive than the sun and a ___ ____. ___ jupiter mass planets orbit the more massive star

Answer 23

binary star, red dwarf, 4

Question 24

a robust formation mechanism must explain not only the ____ properties of the solar system, but also the ____ ____ and ___ distribution, including their frequently large ____. Particular challenges are posed by the large number of close-in planets with a < ____ AU where high temperatures and relatively small amount of ____ ___ would preclude accretion _____ ___

Answer 24

observable, exoplanet frequency, mass, eccentricies, 0.2, protostellar matter, in situ

Question 25

Planets migrate based on interactions with the _____ ___ ____, and depends on the ___ of the exoplanet

Answer 25

protoplanetary gas disk, mass

Question 26

_____ ____ traps two migrating planets in a mean motion resonance, with both interacting with the disk. In this case type ___ migration can cause the orbits to ____, pushing massive planets to very ____ orbits.

Answer 26

resonant trapping, II, expand, large

Question 27

A nearby planet can lift a ___ on the star. The tide can lag or ___ the location of the planet.

Answer 27

tide, lead

Question 28

The classical theory of tides is based on the idea that the effect of ____ is to cause the tidal response to ___ behind the force with a constant _____ with the phase lag giving rise to net ___ ___ and to a dissipation of energy.

Answer 28

dissipation, lag, time-lag, tidal torque

Question 29

The tidal bulge lifted on the star by the planet causes it’s ____ to change with time, while changing the ___ of the star

Answer 29

orbit, spin

Question 30

The first known metal-polluted white dwarf, ___ ____ ___, was the first evidence for extrasolar planets. Around _____% of white white dwarfs have ____ ___ in their spectra, which is notable because any ____ elements in a white dwarf should sink into the star’s interior in just a small fraction of the star’s lifetime.

Answer 30

van maanen 2, 25-33, metal lines, heavy

Question 31

Over the course of about a billion years at the end of it’s life, a star will get gradually expand to ___ of solar radii, staying __ and brightening to ____ solar luminosities (red giant). It will then ___ dramatically to about ___ solar radii and warm up while ___ burning in its core for about ____ million years. It will then expand again to hundreds of solar radii, cooling and ___ while losing ___ its mass over a few million years

Answer 31

tens, cool, 1000, shrink, 10, He, 100, brightening, half

Question 32

About ____% of young white dwarfs have metal lines that indicate ongoing ___. The white dwarf ___ ____ exhibits ___ different heavy metals indicating that the debris is approximately _____.

Answer 32

30, accretion, GD 362, 16, terrestrial

Question 33

a stream of charged particles ejected from the star

Answer 33

stellar winds

Question 34

Stellar winds could cause the high energy ____ seen in some systems and set the _____ time scale of the close-in planet, along with _______ ______.

Answer 34

emissions, migration, tidal torques

Question 35

Extrasolar planets are often much closer than ___ is to our sun, so we have to focus more on interactions between the star and the planets. They can interact through ___ ___, ___ ____, ____ and _______ ____

Answer 35

magnetic flares, stellar winds, flares, non-thermal emission

Question 36

The transiting super earth ___ ____ gets 7.4E18 W of ____ from the stellar corona at _______ K and is losing mass at 1.3E7 kg/s for a total of up to ___ earth masses

Answer 36

GJ 214, X-rays, 3.5E6K, 6

Question 37

Charged particles come together on ___ ____ lines and orbit and accelerate. They can also generate ___ ____. Satellites lie within the planets’ ____ and interact with them. As a ____ ___ collides with a planet’s magnetosphere high energy particles are produced which generate _______ emission.

Answer 37

magnetic field, radio waves, magnetosphere, stellar wind, radio

Question 38

With a pH close to ___, ___ ___ is literally a river of acid. Acid-loving microorganisms (_____) not only thrive in these waters, their _____ activities help generate the acid in the first place. The rusty red colour that gives the river its name comes from high levels of ____ dissolved in the waters

Answer 38

2, rio tinto, acidophiles, metabolic, iron

Question 39

The waters of an evaporative salt pond near ___ ___ are coloured pink by thriving communities of _______ organisms. These waters are ___ x as salty as seawater, enough for ______ to begin crystallize out, yet some organisms can survive and thrive in these conditions

Answer 39

san fransisco, photosynthetic, 10, NaCl

Question 40

____ orbits the closest to jupiter and experiences the strongest ___ ___ by jupiter’s gravity. ____ shows a surface scarred by billions of years’ worth of craters. ____ orbits at a distance where Jupiter’s tidal heating may be just right to sustain a ___ ___ ocean beneath its icy crust.

Answer 40

IO, tidal heating, callisto, europa, liquid water

Question 41

Europa has relatively scarce ____, meaning it is geologically young. The network of coloured ridges and ____ suggest a constant activity and ____. Galileo’s instruments strongly suggest the presence of a massive ocean of _____ liquid water beneath the icy crust

Answer 41

craters, cracks, motion, salty

Question 42

Saturn’s moon _____ has a south polar region that was found to have multiple plumes of ___ and ___ that combined, are venting about ____ kg of material / second into space. Features suggest ____ ocean like Europa.

Answer 42

Enceladus, ice, gas, 250, sub-ice

Question 43

saturn’s moon ____ has a hazy orange glow due to it’s thick _____. The atmosphere is mostly ____ but also contains ___ and potentially a variety of complex ___ ____

Answer 43

titan, atmosphere, nitrogen, methane, organic compounds

Question 44

Kepler ___ is somewhat smaller and cooler than the sun, located ___ light years from earth. Planets kepler __ and____, are located in the habitable zone.

Answer 44

62, 1200, 62e, 62f

Question 45

Kepler ____is nearly identical to the sun, located _____ light years from earth. Kepler 452b’s radius is ___% larger than earth’s, and the mass is ____ times greater. The planet may not be ____, and the surface gravity is ____ x that of earth, with a period of ___ earth days. There is likely more ____ heat, leading to more volcanism

Answer 45

452, 1400, 60, 5, rocky, 2, 385, internal

Question 46

there are as many planets as there are ___ in the galaxy. Additionally, ____ planets are common, and there are a large range of ____ ___, including within our best understanding of the habitable zone. Planets have been found orbiting many different ____ of stars.

Answer 46

stars, terrestrial, semi-major axes, types

Question 47

The fermi paradox posits that if civilizations are long lasting (____ Gyr), and capable of ___ ____, it would only take ____Myr to colonize to new planets. Then every ____ planet in the galaxy would already be colonized.

Answer 47

1, interstellar travel, 30, habitable