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NASA Uses Transit Photometry to Find Life Supporting Planets

NASA Uses Transit Photometry to Find Life Supporting PlanetsThe TESS satellite is using transit photometry to search the skies for planets that support life. In its two-year mission, TESS is expected to find about 300 Earth-sized or Super-Earth-sized exoplanets. Finding each planet is the next step in the search for life outside the solar system.

What Is TESS?

The Transiting Exoplanet Survey Satellite (TESS) is on a mission to find exoplanets. TESS is surveying hundreds of thousands of the brightest stars near the sun with the use of four wide-FOV CCD cameras. It launched on April 18, 2018, aboard a SpaceX Falcon 9. It will survey the entire sky over its two-year mission.

The TESS satellite will catalog thousands of exoplanet candidates. Once its list is compiled, the TESS mission will use ground-based observations to confirm that the exoplanets it detected are not false positives. TESS will scan the entire sky by breaking it up into 26 sectors. The powerful cameras will point at each sector for 27 days.

What Is Transit Photometry?

Transit photometry is used to detect distant planets. The method involves measuring the minute dimming of a star as the planet passes between the star and Earth. The passage is referred to as a transit. When the dimming is detected at regular intervals for a fixed amount of time, it’s highly probable that the transit is a planet orbiting the star.

Transit photometry is our most effective and sensitive method for detecting extrasolar planets. Transits provide scientists with vital information about the planet. The decrease in the star’s luminosity indicates the planet’s size. The planet’s true mass can also be estimated. With that data, its density can also be calculated. Transit data also indicates the atmosphere’s composition and the planet’s temperature.

Planets Already Found By TESS

With the use of its powerful cameras on the spacecraft and the transit photometry method, two Earth-sized worlds orbiting Teegarden’s star (a red dwarf that’s about 12 light-years away from the Solar System, located in the constellation of Aries) were found that meet just about every requirement for supporting life. The planets are almost the same mass as earth; they are billions of years old, and they’re orbiting their star at a distance that would allow the support of water flow and habitable temperatures. Teegarden’s star also appears to be stable. 

Two other planets, one that is Earth-sized, and its hot sub-Neptune companion were found orbiting an orange main-sequence star known as HD 21749. The sub-Neptune planet has an orbital period of about 36 days. It has about 23 times the Earth’s mass. Measuring the Earth-sized planet is difficult because it takes just eight days to orbit the star. With each planet detected, scientists are improving their methods for taking accurate measurements.

You may also be interested in reading our Optics in Life Science Applications on Vision Online.

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