Australian Sky & Telescope - April 2018

20 AUSTRALIAN SKY & TELESCOPE April 2018

NASA’s next planet-hunting

mission will survey roughly

200,000 nearby stars for

signs of alien worlds.

L

ookingupatadarknightskywecanseethousandsof

stars.Everystarisasun,andifourSunhasplanets,

then it makes sense that the other stars would have

planets, too. And they do. Astronomers now know of

thousandsofthese‘exoplanets,’andtheysuspectthatnearly

everystarhasaplanetarysystem,meaningourMilkyWay

Galaxy is teeming with alien worlds.

ThankslargelytothepioneeringKeplerspacetelescope,we

alsonowknowthatsmall,rockyexoplanetsarecommonand

thatplanetarysystemsareastonishingintheirdiversity.

Butmanyofourexoplanetsearcheshavetargetedspecific

areasofsky.Thenaturalnextstepistodoaspace-based

all-skysurvey.Aspecificplanforjustsuchasurveymission

wasenvisionedadecadeagobymyMITcolleaguesGeorge

RickerandRolandVanderspek,incollaborationwithDavid

Latham at the Smithsonian Astrophysical Observatory. The

realisationofthismissionisthesoon-to-be-launchedNASA

Transiting Exoplanet Survey Satellite (TESS), which George

leadsasprincipalinvestigator(PI)andRolandasdeputyPI.

ThemotivationbehindTESSistofindplanetstransiting

starsrelativelynearEarth.Nearbystarsgenerallylook

brightertousthandistantones,andwithallthatadditional

lightreachingus,itwillbeeasierforustodetectthetinyblip

The Transiting

Exoplanet Hunter

TS

THE EXOPLANETS NEXT DOOR by Sara Seager