NASA's TESS mission spots Earth-size exoplanet

NASA's planet-hunting TESS mission has found its first Earth-size exoplanet in a star system only 53 light-years from Earth. Another exoplanet, a warm mini-N...

Posted: Apr 15, 2019 2:38 PM

NASA's planet-hunting TESS mission has found its first Earth-size exoplanet in a star system only 53 light-years from Earth. Another exoplanet, a warm mini-Neptune, was found in the same system.

"It's so exciting that TESS, which launched just about a year ago, is already a game-changer in the planet-hunting business," Johanna Teske, author of a study describing the planets and Hubble Postdoctoral Fellow at the Carnegie Institution for Science, said in a statement. "The spacecraft surveys the sky and we collaborate with the TESS follow-up community to flag potentially interesting targets for additional observations using ground-based telescopes and instruments."

The Earth-size planet, dubbed HD 21749c, completes an orbit of its host star every eight days. Its planetary sibling, HD 21749b, is about 23 times Earth's mass and has a radius about 2.7 times that of Earth. This puts the exoplanet in the category of a sub-Neptune or mini-Neptune.

The study was published in The Astrophysical Journal Letters on Monday.

Researchers determined that the density suggests that the mini-Neptune has a substantial atmosphere. But it's not a rocky planet, like Earth, which could make for insightful followup observations about how the atmosphere is composed and its evolution.

The star that both planets orbit has the equivalent of 80% of our sun's mass.

Most of the exoplanets TESS will find are expected to have orbital periods of 10 days or less. The mini-Neptune was an exciting find for researchers because of its orbital period of 36 days.

This made the discovery more challenging. The researchers used the Planet Finder Spectrograph on the Magellan II telescope at Las Campanas Observatory in Chile to confirm that the signals picked up by TESS were planets. This device also measured the mass of the mini-Neptune.

Mass is key for exoplanet discovery because it enables the determination of density or even chemical composition.

"There was quite some detective work involved, and the right people were there at the right time," said Diana Dragomir, lead study author and Hubble Fellow at the Massachusetts Institute of Technology's Kavli Institute for Astrophysics and Space Research, in a statement. "But we were lucky, and we caught the signals, and they were really clear."

The researchers hope to learn more about the Earth-size planet, as well.

"Measuring the exact mass and composition of such a small planet will be challenging, but important for comparing HD 21749c to Earth," said Sharon Wang, study author and Carnegie Institution for Science postdoctoral fellow, in a statement. "Carnegie's [Planet Finder Spectrograph] team is continuing to collect data on this object with this goal in mind."

TESS will look for exoplanets using the transit method, observing slight dips in stars' brightness as planets pass in front of them. Bright stars allow for easier followup study through ground- and space-based telescopes.

NASA expects TESS to allow for the cataloging of more than 1,500 exoplanets, but it has the potential to find thousands. Of these, officials anticipate, 300 will be Earth-size exoplanets or double-Earth-size super Earths. Those planets could be the best candidates for supporting life outside our solar system. Like Earth, they are small, rocky and usually within the habitable zones of their stars, meaning liquid water can exist on the surface.

TESS is considered a "bridge to the future," finding exoplanet candidates to study in more detail.

These exoplanets will be studied so NASA can determine the best targets for missions like the James Webb Space Telescope. That telescope, launching in 2021, would be able to characterize the details and atmospheres of exoplanets in ways scientists have not been able to do.

But TESS will also help researchers measure mass and maybe even the composition of planetary atmospheres.

"For stars that are very close by and very bright, we expected to find up to a couple dozen Earth-sized planets," Dragomir said. "And here we are -- this would be our first one, and it's a milestone for TESS. It sets the path for finding smaller planets around even smaller stars, and those planets may potentially be habitable."

Minnesota Coronavirus Cases

Data is updated nightly.

Confirmed Cases: 57162

Reported Deaths: 1660
CountyConfirmedDeaths
Hennepin18197820
Ramsey7047261
Dakota4049103
Anoka3410113
Stearns284220
Washington193843
Nobles17496
Olmsted163523
Scott141017
Mower10842
Rice10028
Blue Earth8595
Wright8205
Carver7922
Clay75240
Kandiyohi6771
Sherburne6577
St. Louis45319
Todd4202
Lyon4163
Freeborn3551
Steele3331
Nicollet32013
Benton3103
Watonwan2990
Winona24916
Crow Wing21313
Martin2045
Le Sueur2021
Beltrami2000
Chisago1821
Otter Tail1793
Goodhue1778
Cottonwood1730
Becker1471
Pipestone1439
McLeod1400
Unassigned14040
Polk1353
Itasca13412
Douglas1320
Waseca1300
Pine1280
Carlton1260
Dodge1230
Murray1221
Isanti1100
Chippewa991
Brown852
Faribault840
Meeker832
Morrison821
Wabasha820
Sibley802
Rock750
Koochiching743
Pennington731
Jackson700
Mille Lacs683
Cass622
Fillmore610
Renville605
Lincoln540
Swift521
Grant511
Yellow Medicine490
Roseau460
Pope450
Houston390
Norman370
Hubbard320
Redwood320
Marshall290
Kanabec281
Wilkin283
Aitkin270
Mahnomen241
Wadena230
Big Stone220
Red Lake200
Lake180
Stevens160
Clearwater150
Traverse100
Lac qui Parle60
Kittson30
Cook20
Lake of the Woods10

Iowa Coronavirus Cases

Data is updated nightly.

Confirmed Cases: 46100

Reported Deaths: 887
CountyConfirmedDeaths
Polk9781203
Woodbury365651
Black Hawk302262
Linn214587
Johnson195915
Dallas179635
Buena Vista178612
Scott161512
Dubuque154929
Marshall139424
Pottawattamie122723
Story111714
Wapello85032
Muscatine83048
Webster7366
Crawford7213
Sioux6022
Cerro Gordo57917
Tama53929
Warren5341
Jasper45825
Wright4441
Plymouth4438
Louisa37814
Dickinson3754
Clinton3213
Washington28810
Hamilton2411
Boone2312
Franklin2256
Bremer1927
Clarke1883
Carroll1821
Emmet1812
Clay1711
Shelby1691
Hardin1660
Marion1550
Allamakee1504
Poweshiek1508
Benton1451
Jackson1411
Des Moines1392
Mahaska13617
Floyd1312
Guthrie1285
Jones1242
Cedar1201
Hancock1172
Butler1152
Buchanan1141
Henry1143
Pocahontas1141
Lyon1060
Madison1052
Clayton993
Cherokee981
Harrison980
Lee973
Taylor930
Humboldt921
Delaware911
Iowa901
Monona900
Winneshiek861
Mills830
Calhoun822
Fayette810
Sac810
Palo Alto800
Kossuth780
Osceola780
Jefferson770
Winnebago770
Mitchell760
Page760
Grundy741
Union721
Monroe677
Worth610
Chickasaw510
Davis501
Lucas504
Howard490
Cass481
Montgomery453
Appanoose433
Greene380
Fremont350
Van Buren331
Keokuk311
Ida290
Audubon281
Decatur220
Adair210
Ringgold211
Wayne181
Adams160
Unassigned00
Rochester
Overcast
61° wxIcon
Hi: 75° Lo: 58°
Feels Like: 61°
Mason City
Overcast
63° wxIcon
Hi: 73° Lo: 58°
Feels Like: 63°
Albert Lea
Clear
63° wxIcon
Hi: 71° Lo: 59°
Feels Like: 63°
Austin
Overcast
63° wxIcon
Hi: 76° Lo: 59°
Feels Like: 63°
Charles City
Overcast
63° wxIcon
Hi: 73° Lo: 60°
Feels Like: 63°
Spotty showers tonight, higher chances for the weekend
KIMT Radar
KIMT Eye in the sky

Latest Video

Image

North Iowa baseball players named to All-Star series

Image

Rising above adversity

Image

Rochester Diversity Council Wants to "Lift Every Voice"

Image

Gov. Reynolds Signs Executive Order Allowing Some Felons to Vote

Image

A resurgent local dairy business

Image

Sara's 10PM Forecast - Wednesday

Image

MN #2 in US for Health Care

Image

Olmsted Health and Human Services healthy budget

Image

Case numbers falling in Iowa

Image

One Book, One Minnesota

Community Events