What can we measure about an exoplanet using the transit method?

The transit method consists of regularly measuring the luminosity of a star in order to detect the periodic decrease in luminosity associated with the transit of an exoplanet. The transit happen when a planet passes in front of its star.

What new information can one gain by observing an exoplanet with both transit photometry and radial velocity?

Because transiting exoplanets orbit in orbital planes that are necessarily edge-on to Earth-based observers, using both the transit method and the radial-velocity method to observe the same planet can provide the planet’s mass and therefore its density and likely composition.

What types of exoplanets are easiest to detect with the transit method?

The most scientifically valuable transiting planets are those orbiting bright stars because these are easiest to study…and it usually means that the stars are quite close to us.

Can we directly observe exoplanets?

NASA’s Hubble Space Telescope has captured the first visible-light image of a planet orbiting a star outside our solar system (Science 10.1126/science. The planet Fomalhaut b was observed at two wavelengths (0.6 μm and 0.8 μm) and can be seen in the lower right of the figure. …

How can astronomers currently determine the temperature of an extrasolar planet?

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. How can astronomers currently determine the temperature of an extrasolar planet? measuring the time it takes for the star’s line-of-sight velocity to cycle from peak to peak.

Can allow astronomers to measure the composition of an extrasolar planets atmosphere?

The most successful method for measuring chemical composition of an exoplanetary atmosphere is the transit spectroscopy method.

Why is it hard to detect the existence of extrasolar planets?

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.

What can we learn about an exoplanet’s atmosphere during a transit?

We can also learn about an exoplanet’s atmosphere during a transit. As it transits, some light will go through its atmosphere and that light can be analyzed to determine what different atmospheric elements influenced its particular dispersion. Atmospheric composition is important to determining habitability.

How can we see exoplanets from far away?

Transits reveal an exoplanet not because we directly see it from many light-years away, but because the planet passing in front of its star ever so slightly dims its light. This dimming can be seen in light curves – graphs showing light received over a period of time.

How do you determine the radius of a planet during transit?

The remaining properties to be determined are radius and density. To determine the planet radius, the brightness drop of the parent star that occurs during a planetary transit is measured. This brightness drop is directly related to the ratio of the planet radius to the radius of its parent star, as shown in the image below.

Why are light curves useful for studying exoplanets?

This dimming can be seen in light curves – graphs showing light received over a period of time. When the exoplanet passes in front of the star, the light curve will show a dip in brightness. This data is part of why transits are so useful: Transits can help determine a variety of different exoplanet characteristics.