TESS is the Transiting Exoplanet Survey Satellite, launched in 2018 from a SpaceX rocket. The TESS mission is to conduct a two-year all-sky survey, expected to reveal thousands of exoplanets around nearby bright stars in what is known as Earth's "solar neighborhood". TESS instruments will monitor to detect transit events, in which exoplanets periodically block part of the light from their host stars as they move along their orbits. TESS will study stars 30-100 times brighter than those surveyed by Kepler and K2 missions, and will cover a sky area 400 times larger than the acclaimed Kepler. The TESS data is expected to enable much easier follow-up observations with Earth-based and space-based telescopes.

This is the TESS home page, packed with information on the mission, images, videos, and related data obtained from the Kepler mission (which is no longer in operation).

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How do astronomers use telescopes and spectrometry to find evidence of a distant planet's atmosphere? This 3-minute video shows how instruments are used to split apart a parent star's light during a planetary transit. Each molecule in an exoplanet's atmosphere absorbs light at a distinct wavelength. These absorption spectra reveal information about the planet's chemical makeup, the height of its atmosphere, and its density.

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For teacher content support, here's an excellent free-access article by Harvard astronomer Laura Kreidberg, who devotes her days trying to answer the question, "Are we alone in the universe?" In this paper, Kreidberg explains the techniques of both transit spectroscopy and occultation spectroscopy. She discusses practical considerations and challenges in determining the composition of exoplanet atmospheres using observational methods currently available. If you're not familiar with how astronomers use data points to create transit curves, you'll understand it after reading this article. You'll also take away a better grasp of the work involved to resolve sets of data into a best-fit line.

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Here's an example of finding a planet through "direct" observation. The ESO's Very Large Telescope (VLT) detected this massive planet (Beta Pictoris) in 2008, but the planet orbits so close to the halo of its sun, instruments at that time couldn't get a viewable resolution. Then in late 2015, the planet began to emerge from its star's halo, allowing it to be directly imaged by the ESO "SPHERE" instrument.

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HARPS is the powerful spectrograph attached to the European Space Agency's La Silla Observatory telescope in Chile. Since 2003, HARPS has been busy finding exoplanets using the radial velocity method. Since 2012, the HARPS spectrograph has had the precision to detect habitable super-Earths, opening a new horizon in planet hunting. The limitation is that HARPS can only detect super-Earths around low mass stars. The James Webb Space Telescope, slated to debut in 2021, will aspire to expand the precision of radial velocity spectroscopy to larger mass stars.

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