Ask Ethan: What Has TESS Accomplished In Its First Year Of Science Operations?
“When it’s a bright, sunny day and you want to see an object in the sky that’s very close to the Sun, what do you do? You hold up a finger (or your whole hand) and block out the Sun, and then look for the nearby object that’s much intrinsically fainter than the Sun. This is exactly what telescopes equipped with coronagraphs do.
With the next generation of telescopes, this will enable us to finally directly-image planets around the closest stars to us, but only if we know where, when, and how to look. This is exactly the type of information that astronomers are gaining from TESS. By the time the James Webb Space Telescope launches in 2021, TESS will have completed its first sweep of the entire sky, providing a rich suite of tantalizing targets suitable for direct imaging. Our first picture of an Earth-like world may well be close on the horizon. Thanks to TESS, we’ll know exactly where to look.”
NASA’s TESS has completed its first year of science operations, where it’s just finished surveying the entire southern celestial hemisphere. With 13 separate observations of 27 days apiece, it’s managed to find over 800 candidate planets, including some spectacular examples of planetary systems that are unlike any we’ve ever seen before.
But the real power of TESS is that it tells us where to look to directly image Earth-sized and super-Earth-sized worlds around stars beyond our own. Find out what we’ve learned, so far, today.
Ask Ethan: Can We Find Exoplanets With Exomoons Like Ours?
“But, by far, the best possibility we have today is through direct measurement of a transiting exomoon. If the planet that’s orbiting the star can make a viable transiting signal, then all it will take is the same serendipitous alignment to have its moon transit the star, and sufficiently good data to tease that signal out of the noise.
This is not a pipe dream, but something that has already occurred once. Based on data taken by NASA’s Kepler mission, the stellar system Kepler-1625 is of particular interest, with a transiting light curve that not only displayed the definitive evidence of a massive planet orbiting it, but of a planet that wasn’t transiting with the exact same frequency you’d expect orbit after orbit.”
If you want to find an exoplanet, the most successful methods are to look for the effect it has on the light from it’s parent star. But what about if you wanted to find an exomoon? There are some subtle effects at play, but if we think hard about what they might be, we can come up with a series of methods that could reveal an exomoon’s presence indirectly, and pinpoint exactly where and when we could look to try and detect one directly. Thought to be a great technique for the upcoming James Webb Space Telescope to take advantage of TESS data, we’ve actually succeeded once already, using the Hubble/Kepler combo!
You may have missed it, but we think we’ve found the first exomoon as of late last year. What does the future hold for exomoons? Find out on this week’s Ask Ethan!
Ask Ethan: What Will Our First Direct Image Of An Earth-Like Exoplanet Look Like?
“[W]hat kind of resolution can we expect? [A] few pixels only or some features visible?”
I’ve got good news and bad news. With the next generation of space-based and ground-based telescopes on the way, we’ll finally be able to image Earth-sized and super-Earth-sized planets around the nearest stars to us directly. Unfortunately, even the largest of these telescopes won’t be able to resolve these planets beyond being a single pixel (with light leaking into the adjacent pixels) in angular size. But even with that limitation, we should be able to recover signatures of continents, oceans, icecaps, clouds, atmospheric contents, water, and potentially even life.
Come find out what we will (and won’t) be able to do with our first direct images of Earth-sized exoplanets, coming to you in just a few years!
Incredible First Discoveries From NASA’s New Exoplanet-Hunting Spacecraft: TESS
“The ultimate goal of TESS is to find possible Earth-like worlds, and star systems which may house rocky, potentially habitable worlds. Because TESS is optimized to scour the stars nearest to us, it’s greatest finds will be among the first targets for future, more powerful observatories that can not only detect these worlds, but measure their atmospheric contents. If we get lucky, some of those worlds might house molecules like water, methane, carbon dioxide, or even oxygen in their atmospheres.
It won’t be a slam-dunk that these worlds are inhabited, but TESS takes us one step closer towards finding the nearest worlds that might be humanity’s greatest hope for finding life outside of our own Solar System. The worlds we’ve found so far are absolutely fascinating, and just a few months into its primary mission, TESS is easily meeting even the loftiest expectations for it. By time the James Webb Space Telescope launches, TESS should provide us with many worlds that just might be the best place to look to take our next great leap towards our ultimate goal: finding an inhabited world.”
NASA’s exoplanet-hunting satellite, TESS, was launched in April of 2018, began taking data in July, and released their first data to the world last month. That data contains around 300 candidate exoplanets, and the first eight of them have already been confirmed. From worlds so hot that they might have liquid rock on their surface to a solar system so strange we’ve never found anything like it, these are the first highlights.
Someday, TESS might lead us to our first world with signs of life on it. Here’s where we are so far.