Our latest space telescope,
Transiting Exoplanet Survey Satellite (TESS), launched in April. This
week, planet hunters worldwide received all the data from the first two months
of its planet search. This view, from four cameras on TESS, shows just one
region of Earth’s southern sky.
The Transiting Exoplanet Survey Satellite (TESS) captured
this strip of stars and galaxies in the southern sky during one 30-minute
period in August. Created by combining the view from all four of its cameras, TESS
images will be used to discover new exoplanets. Notable features in this swath
include the Large and Small Magellanic Clouds and a globular cluster called NGC
104. The brightest stars, Beta Gruis and R Doradus, saturated an entire column
of camera detector pixels on the satellite’s second and fourth cameras.
Credit: NASA/MIT/TESS
The data in the images from TESS will soon lead to discoveries of
planets beyond our solar system – exoplanets. (We’re at 3,848 so far!)
But first, all that data (about 27 gigabytes a day) needs to be
processed. And where do space telescopes like TESS get their data cleaned up?
At the Star Wash, of course!
TESS sends about 10 billion pixels of data to Earth
at a time. A supercomputer at NASA Ames in Silicon Valley processes the raw
data, turning those pixels into measures of a star’s brightness.
And that brightness? THAT’S HOW WE FIND PLANETS! A dip in a star’s
brightness can reveal an orbiting exoplanet in transit.
TESS will spend a year studying our southern sky, then will turn
and survey our northern sky for another year. Eventually, the space telescope
will observe 85 percent of Earth’s sky, including 200,000 of the brightest and
closest stars to Earth.
This spectacular image, the first released
using all four of TESS’ cameras, shows the satellite’s full field of view. It
captures parts of a dozen constellations, from Capricornus
(the Sea Goat) to Pictor
(the Painter’s Easel) — though it might be hard to find familiar constellations
among all these stars! The image even includes the Large and Small Magellanic
Clouds, our galaxy’s two largest companion galaxies.
The science community calls this image “first
light,” but don’t let that fool you — TESS has been seeing light since it
launched in April. A first light image like this is released to show off the
first science-quality image taken after a mission starts collecting science
data, highlighting a spacecraft’s capabilities.
During those first few weeks, we also got a
sneak peek of the sky through one of TESS’s four cameras. This test image
captured over 200,000 stars in just two seconds! The spacecraft was pointed
toward the constellation Centaurus when it snapped this picture. The bright
star Beta
Centauri is visible at the lower left edge, and the edge
of the Coalsack
Nebula is in the right upper corner.
After settling into orbit, scientists ran a
number of checks on TESS, including testing its ability to collect a set of
stable images over a prolonged period of time. TESS not only proved its ability
to perform this task, it also got a surprise! A comet named C/2018 N1 passed through TESS’s cameras
for about 17 hours in July.
The images show a treasure
trove of cosmic curiosities. There are some stars whose
brightness changes over time and asteroids visible as small moving white dots.
You can even see an arc of stray light from Mars, which is located outside the
image, moving across the screen.
Now that TESS has settled into orbit and has
been thoroughly tested, it’s digging into its main mission of finding planets around other stars.
How will it spot something as tiny and faint as a planet trillions of miles
away? The trick is to look at the star!
So far, most
of the exoplanets we’ve found were detected by looking
for tiny dips in the brightness of their host stars. These dips are caused by
the planet passing between us and its star – an event called a transit. Over
its first two years, TESS will stare at 200,000 of the nearest and brightest stars
in the sky to look for transits to identify stars with planets.
TESS will be building on the legacy of NASA’s Kepler spacecraft, which also used
transits to find exoplanets. TESS’s target stars are about 10 times closer than
Kepler’s, so they’ll tend to be brighter. Because they’re closer and brighter,
TESS’s target stars will be ideal candidates for follow-up studies with current
and future observatories.
TESS is challenging over 200,000 of our
stellar neighbors to a staring contest! Who knows what new amazing planets
we’ll find?
We’re getting ready to start our next mission to find new worlds! The Transiting Exoplanet Survey Satellite (TESS) will find thousands of planets beyond our solar system for us to study in more detail. It’s preparing to launch from our Kennedy Space Center at Cape Canaveral in Florida.
Once it launches, TESS will look for new planets that orbit bright stars relatively close to Earth. We’re expecting to find giant planets, like Jupiter, but we’re also predicting we’ll find Earth-sized planets. Most of those planets will be within 300 light-years of Earth, which will make follow-up studies easier for other observatories.
TESS will find these new exoplanets by looking for their transits. A transit is a temporary dip in a star’s brightness that happens with predictable timing when a planet crosses between us and the star. The information we get from transits can tell us about the size of the planet relative to the size of its star. We’ve found nearly 3,000 planets using the transit method, many with our Kepler space telescope. That’s over 75% of all the exoplanets we’ve found so far!
TESS will look at nearly the entire sky (about 85%) over two years. The mission divides the sky into 26 sectors. TESS will look at 13 of them in the southern sky during its first year before scanning the northern sky the year after.
What makes TESS different from the other planet-hunting missions that have come before it? The Kepler mission (yellow) looked continually at one small patch of sky, spotting dim stars and their planets that are between 300 and 3,000 light-years away. TESS (blue) will look at almost the whole sky in sections, finding bright stars and their planets that are between 30 and 300 light-years away.
TESS will also have a brand new kind of orbit (visualized below). Once it reaches its final trajectory, TESS will finish one pass around Earth every 13.7 days (blue), which is half the time it takes for the Moon (gray) to orbit. This position maximizes the amount of time TESS can stare at each sector, and the satellite will transmit its data back to us each time its orbit takes it closest to Earth (orange).
Kepler’s goal was to figure out how common Earth-size planets might be. TESS’s mission is to find exoplanets around bright, nearby stars so future missions, like our James Webb Space Telescope, and ground-based observatories can learn what they’re made of and potentially even study their atmospheres. TESS will provide a catalog of thousands of new subjects for us to learn about and explore.
Launch teams are standing down today to conduct additional Guidance Navigation and Control analysis, and teams are now working towards a targeted launch of the Transiting Exoplanet Survey Satellite (TESS) on Wednesday, April 18. The TESS spacecraft is in excellent health, and remains ready for launch. TESS will launch on a Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.
So you’re thinking…who’s TESS? But, it’s more like: WHAT is TESS?
The Transiting Exoplanet Survey Satellite (TESS) is an explorer-class planet finder that is scheduled to launch in April 2018. This mission will search the entire sky for exoplanets — planets outside our solar system that orbit sun-like stars.
In the first-ever space borne all-sky transit survey, TESS will identify planets ranging from Earth-sized to gas giants, orbiting a wide range of stellar types and orbital distances.
The main goal of this mission is to detect small planets with bright host stars in the solar neighborhood, so that we can better understand these planets and their atmospheres.
TESS will have a full time job monitoring the brightness of more than 200,000 stars during a two year mission. It will search for temporary drops in brightness caused by planetary transits. These transits occur when a planet’s orbit carries it directly in front of its parent star as viewed from Earth (cool GIF below).
TESS will provide prime targets for further, more detailed studies with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future.
TESS and Kepler address different questions: Kepler answers “how common are Earth-like planets?” while TESS answers “where are the nearest transiting rocky planets?”
What do we hope will come out of the TESS mission?
The main goal is to find rocky exoplanets with solid surfaces at the right distance from their stars for liquid water to be present on the surface. These could be the best candidates for follow-up observations, as they fall within the “habitable zone” and be at the right temperatures for liquid water on their surface.
TESS will use four cameras to study sections of the sky’s north and south hemispheres, looking for exoplanets. The cameras would cover about 90 percent of the sky by the end of the mission. This makes TESS an ideal follow-up to the Kepler mission, which searches for exoplanets in a fixed area of the sky. Because the TESS mission surveys the entire sky, TESS is expected to find exoplanets much closer to Earth, making them easier for further study.
