Why have only massive planets with short orbital periods been discovered so far?
The high masses and short orbital periods of the planets discovered so far makes them easier to detect than conventional Jupiter-like planets with long periods.
What was so surprising about the first extrasolar planets that they forced a change in our theory of planet formation?
What was so surprising about the first extrasolar planets that they forced a change in our theory of planet formation? They were massive like Jupiter, but very close to their host star.
What might prevent astronomers from finding planets with orbits like our Jovian planets?
No telescope is powerful enough to detect the faint light from a distant planet. Their light is overwhelmed by the light from their star. Extrasolar planets give off light at different wavelengths than planets in our solar system. Telescopes are too busy with other projects.
Which of the following is a reason that astronomers have not found giant planets with the orbit of Neptune around other stars?
Which of the following is a reason that astronomers have not found many giant planets with the orbit of Neptune around other stars? Neptune takes 165 years to go around the Sun; getting information about just one cycle of such a planet's orbit around another star would take astronomers 165 years.
What must be true about the orbit of a planet discovered by the transit method?
What must be true about the orbit of a planet discovered by the transit method? As seen from Earth, the planet's orbit must be nearly parallel to our line of sight.
Why does the Doppler method generally give a planet’s minimum mass rather than an exact mass?
Why does the Doppler method generally give a planet's "minimum mass" rather than an exact mass? The size of the Doppler shift that we detect depends on the tilt of a planet's orbit. Which of the following statements is not true about the planets so far discovered around other stars?
Why are planets with long orbital periods among the last to be discovered quizlet?
Why are planets with long orbital periods among the last to be discovered? Very few of these planets exist. They will never block any of the light from their host star. They are harder to see against the bright light of the host star.
Which of the following methods has led to the most discoveries of extrasolar planet candidates?
Which of the following methods has led to the most discoveries of extrasolar planet candidates? 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.
Why are so many of the extrasolar planets that have been detected thus far as massive or more massive than Jupiter?
This is because the parent star will wiggle more with a large planet nearby, thereby creating a larger and more easily detectable spectral shift. Most planets discovered around other stars have been very massive and orbit extremely close to their parent star.
What do astronomers mean by a selection effect explain why the detection of giant planets in close orbits does not necessarily mean our solar system is unusual?
Explain why the detection of giant planets in close orbits does not necessarily mean our Solar System is unusual. A selection effect is a bias in a detection technique. It is specific to a certain class of objects and they are selected. The giants planets tend to be found because of the gravity detection.
Why are so many of the extrasolar planets that have been detected thus far as?
It was only over the past decade that we finally obtained unambiguous evidence for the existence of extrasolar planets. The reason why it took so long to find these objects is the fact that planets are dark objects very close to an extremely bright source, their host star.
Why is it difficult to discover long period exoplanets using the transit method?
The main difficulty with the transit-photometry method is that in order for the photometric effect to be measured, a transit must occur. Not all planets orbiting other stars transit their stars as seen from Earth; a distant planet must pass directly between its star and Earth.
Why have most extrasolar planets detected with the transit method been found in short period orbits fairly close to their host stars?
Why do most extrasolar planets discovered by the Doppler method have orbits relatively close to their host stars? These close-in planets are easier to detect because they cause larger Doppler shifts.
What are the strengths and limitations of the Doppler method?
What are the strengths and limitations of the Doppler method? The Doppler technique has the main advantage of being able to detect planets in a wide range of orbits—as long as the orbit is not face-on. Its disadvantage is that it can yield only the planet's mass and orbital properties.
How do we expect that the first Earth sized extrasolar planets will be discovered if they exist )?
How do we expect that the first Earth-sized extrasolar planets will be discovered (if they exist)? observing a star carefully enough to notice that it is experiencing a gravitational tug caused by an unseen planet.
Why have most extrasolar planets detected with the transit method been found with orbits fairly close to their host stars?
Why do most extrasolar planets discovered by the Doppler method have orbits relatively close to their host stars? These close-in planets are easier to detect because they cause larger Doppler shifts.
What is the main reason it is so challenging to detect extrasolar planets?
Because planets are much fainter than the stars they orbit, extrasolar planets are extremely difficult to detect directly.
Why is finding exoplanets difficult?
Exoplanets are very hard to see directly with telescopes. They are hidden by the bright glare of the stars they orbit. So, astronomers use other ways to detect and study these distant planets. They search for exoplanets by looking at the effects these planets have on the stars they orbit.
What is the relationship between transit duration and orbital period?
The length of time between each transit is the planet's "orbital period", or the length of a year on that particular planet. Not all planets have years as long as a year on the Earth! Some planets discovered by Kepler orbit around their stars so quickly that their years only last about four hours!
Why are so many of the extrasolar planets that have been detected thus far in orbits so close to their stars?
While the Doppler technique is most widely used for detecting extrasolar planets, it is best suited to look for very massive planets orbiting close to their parent star. This is because the parent star will wiggle more with a large planet nearby, thereby creating a larger and more easily detectable spectral shift.
Why were scientists surprised when they first discovered the existence of planets?
Their discovery came as a surprise to scientists because in our solar system jovian planets are only found far from the Sun. Our modern theory of solar system formation—the nebular theory—successfully accounts for all the major features of our own solar system.
What advantages are gained if a planet can be detected by both methods?
Advantages gained if a planet can be detected by both methods. If a planet can be detected by both methods, then we can find its density, an indication of its composition.
Why did it take astronomers until 1995 to discover the first exoplanet orbiting another star like the sun?
Why did it take astronomers until 1995 to discover the first exoplanet orbiting another star like the Sun? The first discovery of an exoplanet took place by finding the changing Doppler shift in the spectrum of the star as the planet moved in orbit around it.
Why have most extrasolar planets detected with the transit method been found with orbits fairly close to their host stars quizlet?
Why do most extrasolar planets discovered by the Doppler method have orbits relatively close to their host stars? These close-in planets are easier to detect because they cause larger Doppler shifts.
What is the biggest problem in detecting exoplanets?
“The fundamental problem is that exoplanets are almost always too small and too dim to look at directly,” she adds. “The only ways we can discover them are indirect – we have to look at how they influence the star that they're orbiting around.
What is the main reason the direct detection method tends to find exoplanets that are far away from their stars?
With this method, it is easier to detect massive planets close to their stars as these factors increase the star's motion. Unlike the radial velocity method, it does not require an accurate spectrum of a star, and therefore can be used more easily to find planets around fast-rotating stars and more distant stars.
What method has detected the most extrasolar planets so far?
Most known exoplanets have been discovered using the transit method. A transit occurs when a planet passes between a star and its observer. Transits within our solar system can be observed from Earth when Venus or Mercury travel between us and the Sun.
Why did it take astronomers until 1995 to discover the first exoplanet orbiting another star like the Sun?
Why did it take astronomers until 1995 to discover the first exoplanet orbiting another star like the Sun? The first discovery of an exoplanet took place by finding the changing Doppler shift in the spectrum of the star as the planet moved in orbit around it.
How were the planets first discovered?
In 1781, William Herschel was looking for binary stars in the constellation of Taurus when he observed what he thought was a new comet. Its orbit revealed that it was a new planet, Uranus, the first ever discovered telescopically.
Why have most new planets discovered around other stars been very large?
Why have most new planets discovered around other stars been very large? A small planet would be hard to detect because it would have little gravitational effect on the star it orbited.