NASA’nın Kepler Uzay Teleskobu’nun son gözlem kampanyası sadece bir ay sürdü. Uzay aracının tutum kontrol yakıtı azalmaya başladığından, konumunu yararlı gözlemler toplayacak kadar uzun süre koruyamadı. Sonunda, gökbilimciler yalnızca yaklaşık yedi günlük yüksek kaliteli verilere sahipti. Bir araştırma ekibi, bir grup vatandaş bilim insanı ve profesyonel astronomla birlikte çalıştı ve son veri parçasında üç gezegen buldu. Kredi: NASA/JPL-Caltech (K. Walbolt)
Astrofizikçiler ve vatandaş bilim adamları, tarafından gözlemlenen son gezegenler arasında sayılan üç ötegezegen keşfettiler.[{” attribute=””>NASA’s retired Kepler space telescope. Throughout its mission, Kepler observed hundreds of thousands of stars and contributed to the identification of over 2,600 confirmed exoplanets. Despite facing mechanical issues, Kepler persevered and continued to uncover new celestial bodies until its final days.
A team of astrophysicists and citizen scientists have identified what may be some of the last planets NASA’s retired Kepler space telescope observed during its nearly decade-long mission.
The trio of exoplanets – worlds beyond our solar system – are all between the size of Earth and Neptune and closely orbit their stars.
”These are fairly average planets in the grand scheme of Kepler observations,” said Elyse Incha, a senior at the University of Wisconsin-Madison. “But they’re exciting because Kepler observed them during its last few days of operations. It showcases just how good Kepler was at planet hunting, even at the end of its life.”
A paper about the planetary trio led by Incha was published in the May 30, 2023 issue of the journal Monthly Notices of the Royal Astronomical Society.
This illustration depicts NASA’s exoplanet hunter, the Kepler space telescope. The agency announced on October 30, 2018, that Kepler has run out of fuel and is being retired within its current and safe orbit, away from Earth. Kepler leaves a legacy of more than 2,600 exoplanet discoveries. Credits: NASA/Wendy Stenzel/Daniel Rutter
Kepler launched in March 2009. The mission’s initial goal was to continuously monitor a patch of sky in the northern constellations Cygnus and Lyra. This long period of observations allowed the satellite to track changes in stellar brightness caused by planets crossing in front of their stars, events called transits.
After four years, the telescope had observed over 150,000 stars and identified thousands of potential exoplanets. It was the first NASA mission to find an Earth-size world orbiting within its star’s habitable zone, the range of distances where liquid water could exist on a planet’s surface.
In 2014, the spacecraft experienced mechanical issues that temporarily halted observations. The Kepler team devised a fix that allowed it to resume operations, switching its field of view roughly every three months, a period called a campaign. This renewed mission, called K2, lasted another four years and surveyed over 500,000 stars.
When Kepler was retired in October 2018, it had aided the discovery of over 2,600 confirmed exoplanets and many more candidates.
The “last light” image taken on September 25, 2018, represents the final page of the final chapter of Kepler’s remarkable journey of data collection. The blackened gaps in the center and along the top of the image are the result of earlier random part failures in the camera. Due to the modular design, the losses did not impact the rest of the instrument. Credit: NASA/Ames Research Center
K2’s final campaign, number 19, lasted only a month. As the spacecraft began to run low on attitude control fuel, it couldn’t maintain its position long enough to collect useful observations. In the end, astronomers only had about seven days of high-quality data from Campaign 19.
Incha and her team worked with the Visual Survey Group, a collaboration between citizen scientists and professional astronomers, to scan this dataset for exoplanets. The citizen scientists hunted for signals of transiting worlds over all Campaign 19’s light curves, which record how monitored stars brightened or dimmed.
“People doing visual surveys – looking over the data by eye – can spot novel patterns in the light curves and find single objects that are hard for automated searches to detect. And even we can’t catch them all,” said Tom Jacobs, a former U.S. Navy officer and Visual Survey Group team member. “I have visually surveyed the complete K2 observations three times, and there are still discoveries waiting to be found.”
Jacobs and others found one transit for each of the three planet candidates, each orbiting a different star, in the high-quality dataset.
After their initial discovery, Incha and her team also went back and looked at the lower-quality data from the rest of Campaign 19 and found one additional transit each from two of the three stars flagged in the visual search.
“The second transits for those two planet candidates helped us confirm their discovery,” said Andrew Vanderburg, an assistant professor of physics at the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MIT) in Cambridge. “No one had found planets in this dataset before, but our collaboration was able to find three. And we’re really pushing up against the last few days, the last few minutes, of observations Kepler collected.”
Illustration of NASA’s Transiting Exoplanet Survey Satellite (TESS) at work. Credit: NASA’s Goddard Space Flight Center
Using the transit information, Incha and her team calculated the worlds’ potential sizes and orbital periods. The smallest planet, K2-416 b, is about 2.6 times Earth’s size and orbits its red dwarf star about every 13 days. K2-417 b, just over three times Earth’s size, also orbits a red dwarf star but completes an orbit every 6.5 days. The final, unconfirmed planet, EPIC 246251988 b, is almost four times Earth’s size and orbits its Sun-like star in around 10 days. (The first two planets take their name from the K2 era of the mission, the last from the Ecliptic Plane Input Catalog (EPIC) of stars in the K2 fields.)
NASA’s Transiting Exoplanet Survey Satellite (TESS), which launched in April 2018, also uses the transit method, surveying large swaths of sky at a time. During August and September 2021, TESS observed the patch of space containing the three new Kepler planets. Astronomers were able to detect two more potential transits for K2-417 b.
Ekim 2018’de, uzayda geçirdiği dokuz yılın ardından NASA’nın Kepler Uzay Teleskobu, görevinin sonuna geldi. O yılın başlarında (Nisan 2018), NASA’nın Transit Transiting Exoplanet Survey Satellite fırlatıldı ve gezegen avı meşalesini aldı.
NASA’nın Greenbelt, Maryland’deki Goddard Uzay Uçuş Merkezi’nde birkaç yıl Kepler görevinde çalışan TESS proje bilimcisi Knicole Colón, “Birçok yönden, Kepler gezegen avı meşalesini TESS’e devretti,” dedi. “Kepler’in veri seti, astronomlar için bir hazine olmaya devam ediyor ve TESS, keşifleri hakkında bize yeni içgörüler sağlamaya yardımcı oluyor.”
Referans: “Kepler’in son gezegen keşifleri: Elyse Incha, Andrew Vanderburg, Tom Jacobs, Daryll LaCourse, Allyson Bieryla, Emily Pass, Steve B Howell, Perry Berlind, Michael Calkins, Gilbert Esquerdo, 19″ K2 kampanyasından iki yeni gezegen ve bir tek geçiş adayı David W Latham ve Andrew W Mann, 30 Mayıs 2023, Royal Astronomical Society’nin Aylık Bildirimleri.
DOI: 10.1093/mnras/stad1049
NASA’nın Kaliforniya Silikon Vadisi’ndeki Ames Araştırma Merkezi, NASA’nın Bilim Misyon Müdürlüğü için Kepler ve K2 görevlerini yönetti. NASA’nın Pasadena, California’daki Jet Tahrik Laboratuvarı, Kepler misyon geliştirmeyi yönetti. Boulder, Colorado’daki Ball Aerospace & Technologies Corporation, uçuş sistemini Boulder’daki Colorado Üniversitesi’ndeki Atmosfer ve Uzay Fiziği Laboratuvarı’nın desteğiyle işletti.
TESS, MIT tarafından yönetilen ve işletilen ve Goddard tarafından yönetilen bir NASA Astrofizik Kaşif görevidir. Ek ortaklar arasında Falls Church, Virginia merkezli Northrop Grumman; NASA Ames; Astrofizik Merkezi | Cambridge, Massachusetts’te Harvard & Smithsonian; MIT’nin Lincoln Laboratuvarı; ve Baltimore’daki Uzay Teleskobu Bilim Enstitüsü. Dünya çapında bir düzineden fazla üniversite, araştırma enstitüsü ve gözlemevi misyona katılıyor.