NASA’s Kepler Space Telescope managed to capture the dimming of a star more than 215-light-years away, alerting scientists to the presence of a tiny planet passing between the star and Earth.
According to a statement issued by NASA, what the Kepler mission scientists discovered was a new planetary system which is home to the smallest planet ever found rotating around a star similar to our sun.
The planetary system orbits Kepler-37, a yellow dwarf star in the Lyra constellation. The star is approximately 215.2-light-years from earth, while the planet is believed to be about 210-light-years from earth. The tiny exoplanet, a planet outside of our solar system, is known as Kepler-37b. The planet is one third the size of earth, smaller than any planter in our solar system, and only slightly larger then the earth’s moon.
The line up compares artist's concepts of the planets in the Kepler-37 system to the moon and planets in the solar system. The smallest planet, Kepler-37b, is slightly larger than our moon, measuring about one-third the size of Earth. Kepler-37c, the second planet, is slightly smaller than Venus, measuring almost three-quarters the size of Earth. Kepler-37d, the third planet, is twice the size of Earth.
How Kepler-37b was discovered
The Kepler space telescope continuously measures the brightness of more than 150,000 stars every 30 minutes. When a planet passes between the star and the Kepler telescope, some of the light emitting from the sun is momentarily blocked. Using data recorded by the telescope, NASA scientists were trying to locate planets relatively the same size as earth near the “habitable zone”, an area of space where liquid may be found on the planet’s surface. It was during that search that scientists were able to "see" 37b, along with its two companion planets, 37c and 37d.
The planet may have been found in the “habitable zone”, but don't expect a space colony on the tiny planet. Making a complete orbit of the sun every thirteen days, Kepler-37b is closer to its sun than Mercury is to ours. According to Space.com, astronomers estimate the surface temperature of the planet to be around 800 degrees Fahrenheit (427 Celsius). The extreme temperature means the planet most likely does not have an atmosphere, making it impossible to support life as we know it.
Thomas Barclay, a research scientist at the NASA Ames Research Center in Moffett Field, CA. told Nature:
“Any water on the surface would disappear very quickly. There is almost no chance of an atmosphere or liquid on the surface.”Determining the size of the planet
In order for astronomers to estimate the size of any planet, they must first know the size of the star the planet orbits. According to NASA's Jet Propulsion Laboratory, scientists looked at the sound waves generated by the boiling motion beneath the surface of Kepler-37. The process is known as asteroseismology.
Similar to church bells, the smaller the star, the higher the tone. The larger the star, the deeper the tone. Listening to the star's tone allows scientists to get an estimate its size. Once scientists have an idea of the star's size, they can use images generated from telescopes to gauge the size of the planet. For instance, if only a third of the sun light is blocked, scientists can determine that the planet is more or less a third of the size of the sun.
Significance of Kepler-37's discovery
Kepler-37 is only a third of the size of our sun. The small size of the sun, and the even smaller size of Kepler-37b, means the high precision instruments on the Kepler Space Telescope allows astronomers to reach a new milestone in locating small planetary systems, a significant step in NASA's ability to explore space.
Francois Fressin, of the Harvard-Smithsonian Center for Astrophysics, finds this significant step fascinating, telling the BBC:
"I think it's an amazing technological achievement to be able to be able to detect small rocks like this. It means we're really in the arena where it's possible to detect all the planets of our Solar System, but around other stars."