- Awareness in space.
NASA’s Kepler Space telescope
What to study?
- For Prelims: About Kepler telescope, TESS.
- For Mains: What are exoplanets, significance of their findings.
Context: NASA’s Transiting Exoplanet Survey Satellite, TESS, has discovered its first Earth-sized exoplanet. The planet, named HD 21749c, is the smallest world outside our solar system that TESS has identified yet.
- The new planet orbits the star HD 21749 — a very nearby star, just 52 light years from Earth. The star also hosts a second planet — HD 21749b — a warm “sub-Neptune” with a longer, 36-day orbit.
While this is the first Earth-sized planet discovered by TESS, other Earth-sized exoplanets have been discovered in the past, mainly by NASA’s Kepler Space Telescope, a since-retired telescope that monitored more than 530,000 stars. In the end, the Kepler mission detected 2,662 planets, many of which were Earth-sized, and a handful of those were deemed to be within their star’s habitable zone — where a balance of conditions could be suitable for hosting life.
About Kepler Mission:
Launched in 2009, the Kepler mission is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-sized and smaller planets in or near the habitable zone and determine the fraction of the hundreds of billions of stars in our galaxy that might have such planets.
About TESS mission:
The Transiting Exoplanet Survey Satellite (TESS) is a NASA mission that will look for planets orbiting the brightest stars in Earth’s sky. It was led by the Massachusetts Institute of Technology with seed funding from Google.
Mission: The mission will monitor at least 200,000 stars for signs of exoplanets, ranging from Earth-sized rocky worlds to huge gas giant planets. TESS, however, will focus on stars that are 30 to 100 times brighter than those Kepler examined. This will help astronomers better understand the structure of solar systems outside of our Earth, and provide insights into how our own solar system formed.
Orbit: TESS will occupy a never-before-used orbit high above Earth. The elliptical orbit, called P/2, is exactly half of the moon’s orbital period; this means that TESS will orbit Earth every 13.7 days.
How it works? It will use transit method to detect exoplanets. It watches distant stars for small dips in brightness, which can indicate that planet has passed in front of them. Repeated dips will indicate planet passing in front of its star. This data has to be validated by repeated observations and verified by scientists.
Sources: the hindu.