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NASA's Transiting Exoplanet Survey Satellite (TESS), shown here as a conceptual illustration, will identify exoplanets in orbit around the brightest stars just outside our solar system. Credit: Goddard Space Flight Center of NASA
NASA's new Transiting Exoplanet Survey Satellite (TESS) satellite is designed to find habitable exoplanets, but with hundreds of thousands of stars similar to those of the sun and smaller, which ones could host planets like ours?
TESS will observe 400,000 stars across the sky to see a planet crossing the face of its star, one of the main methods of identifying exoplanets.
A team of astronomers from Cornell, Lehigh and Vanderbilt Universities has identified the most promising targets for this research in the new "Star Catalog of TESS Living Area", published in Letters from the Astrophysical Journal. The lead author is Lisa Kaltenegger, Professor of Astronomy and Director of the Carl Sagan Institute in Cornell and a member of the TESS Science Team.
This new catalog is inspired from the one originally developed in Vanderbilt, which contains hundreds of millions of stars. Using data from several sources, including the Vanderbilt KELT telescope and the "flicker" analysis method developed at Vanderbilt, Stevenson's professor of physics and astronomy , Keivan Stassun, has been working since 2012 to reduce the field of observation from 470 million visible stars. TESS to the 250,000 more likely to host a planet like ours.
Vanderbilt postgraduate students, graduate students, and postdoctoral scientists associated with the Vanderbilt Initiative in Data-Driven Astrophysics (VIDA), as well as students, developers, and data visualizers associated with Frist completed the work to sift through such a huge data volume Center for Autism and Innovation.
"Our ambition is not only to detect hundreds of Earth-like worlds in other solar systems, but also to find them around our nearest solar systems," said Stassun. "In a few years, we may know that there are other habitable planets, with breathable atmospheres.Of course, we will not know yet whether there is something, or who It is a remarkable moment in the history of humanity and a great step forward for our understanding of our place in the universe. "
The catalog identifies 1,823 stars for which TESS is sensitive enough to spot Earth-like planets, slightly larger than the Earth, which receive a radiation equivalent to that which the Earth receives from our sun. For 408 stars, TESS can see a planet as small as the Earth, with a similar irradiation, in a single transit.
"Life could exist on all kinds of worlds, but the one we know can support life belongs to us, so it makes sense to start by looking for Earth-like planets," said Kaltenegger. "This catalog is important for TESS because anyone working with the data wants to know which stars we can find the nearest Earth analogues."
Kaltenegger runs a program on TESS that observes in detail the 1,823 stars of the catalog, in search of planets. "I have 408 new favorite stars," Kaltenegger said. "It's amazing that I do not have to pick one, I have to look for hundreds of stars."
The confirmation of an exoplanet has been observed and the determination of the distance that separates it from its star requires the detection of two passages through the star. The 1,823 stars that the researchers identified in the catalog are those that allow TESS to detect two planetary transits during its mission. These orbital periods place them in the middle of the habitable zone of their star.
The liveable area is the area around a star where water can be liquid to the surface of a rocky planet, so considered ideal for sustaining life. As the researchers note, planets outside the habitable zone could certainly harbor life, but it would be extremely difficult to detect signs of life on such frozen planets without stealing.
The catalog also identifies a subset of 227 stars for which TESS can not only probe planets receiving the same irradiation as the Earth, but for which TESS can also probe deeper, covering the entire extent of the habitable zone. until March, colder. -like orbits. This will allow astronomers to probe the diversity of potentially habitable worlds around hundreds of cold stars during the duration of the TESS mission.
The stars selected for the catalog are bright, fresh dwarves with temperatures between 2,700 and 6,000 degrees Kelvin. The stars in the catalog are selected because of their brightness; the closest are only about 4 light years from Earth.
"We do not know how many planets our TESSES will find among the hundreds of stars in our catalog and whether they will be habitable," said Kaltenegger, "but the chances of doing so are in our favor. There are many rocky planets in the habitable zone of cold stars, like those in our catalog, and we can not wait to see what worlds we will find. "
The catalog has a total of 137 stars in the continuous viewing area of NASA's James Webb Space Telescope, which is currently under construction. Webb will be able to observe them to characterize in depth all the planets found by TESS and to look for signs of life in their atmospheres.
The researchers indicate that the identified TESS planets may also be excellent targets for observations with the very large ground-based telescopes being built, as the brightness of their host stars would make them easier to characterize.
Explore further:
MuSCAT2 to find Earth-like planets in the TESS era
More information:
L. Kaltenegger et al, Star Catalog of the TESS Habitable Zone, The astrophysical journal (2019). dx.doi.org/10.3847/2041-8213/ab0e8d
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