Kepler telescope spies details of TRAPPIST-1 system’s outermost planet

Peter Kelley

News and Information

A University of Washington-led international team of astronomers has used data gathered by the Kepler Space Telescope to observe and confirm details of the outermost of seven exoplanets orbiting the star TRAPPIST-1.

They confirmed that the planet, TRAPPIST-1h, orbits its star every 18.77 days, is linked in its orbital path to its siblings and is frigidly cold. Far from its host star, the planet is likely uninhabitable — but it may not always have been so.

UW doctoral student Rodrigo Luger is lead author on a paper published May 22 in the journal Nature Astronomy.

“TRAPPIST-1h was exactly where our team predicted it to be,” Luger said. The researchers discovered a mathematical pattern in the orbital periods of the inner six planets, which was strongly suggestive of an 18.77 day period for planet h.

“It had me worried for a while that we were seeing what we wanted to see. Things are almost never exactly as you expect in this field — there are usually surprises around every corner, but theory and observation matched perfectly in this case.”

TRAPPIST-1 is a middle-aged, ultra cool dwarf star, much less luminous than the sun and only a bit larger than the planet Jupiter. The star, which is nearly 40 light-years or about 235 trillion miles away in the constellation of Aquarius, is named after the ground-based Transiting Planets and Planetesimals Small Telescope (TRAPPIST), the facility that first found evidence of planets around it in 2015.

The TRAPPIST survey is led by Michael Gillon of the University of Liège, Belgium, who is also a coauthor on this research. In 2016, Gillon’s team announced the detection of three planets orbiting TRAPPIST-1 and this number was upped to seven in a subsequent 2017 paper. Three of
TRAPPIST-1’s planets appear to be within the star’s habitable zone, that swath of space around a star where a rocky planet could have liquid water on its surface, thus giving life a chance.

Such exoplanets are detected when they transit, or pass in front of, their host star, blocking a measurable portion of the light. Gillon’s team was able to observe only a single transit for TRAPPIST-1h, the farthest-out of the star’s seven progeny, prior to the data analyzed by Luger’s team.

Luger led a multi-institution international research team that studied the TRAPPIST-1 system more closely using 79 days of observation data from K2, the second mission of the Kepler Space Telescope. The team was able to observe and study four transits of TRAPPIST-1h across its star.

The team used the K2 data to further characterize the orbits of the other six planets, help rule out the presence of additional transiting planets, and determine the rotation period and activity level of the star. They also discovered that TRAPPIST-1’s seven planets appear linked in a complex dance known as an orbital resonance where their respective orbital periods are mathematically related and slightly influence each other.

“Resonances can be tricky to understand, especially between three bodies. But there are simpler cases that are easier to explain,” Luger said. For instance, closer to home, Jupiter’s moons Io, Europa and Ganymede are set in a 1:2:4 resonance, meaning that Europa’s orbital period is exactly twice that of Io, and Ganymede’s is exactly twice that of Europa.

These relationships, Luger said, suggested that by studying the orbital velocities of its neighbor planets they could predict the exact orbital velocity, and hence also orbital period, of TRAPPIST-1h even before the K2 observations. Their theory proved correct when they located the planet in the K2 data.

TRAPPIST-1’s seven-planet chain of resonances established a record among known planetary systems, the previous holders being the systems Kepler-80 and Kepler-223, each with four resonant planets. The resonances are “self-correcting,” Luger said, such that if one planet were to somehow be nudged off course, it would lock right back into resonance. “Once you’re caught into this kind of stable resonance, it’s hard to escape,” he said.

All of this, Luger said, indicates that these orbital connections were forged early in the life of the TRAPPIST-1 system, when the planets and their orbits were not fully formed.

“The resonant structure is no coincidence, and points to an interesting dynamical history in which the planets likely migrated inward in lock-step,” Luger said. “This makes the system a great testbed for planet formation and migration theories.”

It also means that while TRAPPIST-1h is now extremely cold — with an average temperature of 173 Kelvin (minus 148 F) — it likely spent several hundred million years in a much warmer state, when its host star was younger and brighter.

“We could therefore be looking at a planet that was once habitable and has since frozen over, which is amazing to contemplate and great for follow-up studies,” Luger said.

Luger said he has been working with data from the K2 mission for a while now, researching ways to reduce “instrumental noise” in its data resulting from broken reaction wheels — small flywheels that help position the spacecraft — that can overwhelm planetary signals.

“Observing TRAPPIST-1 with K2 was an ambitious task,” said Marko Sestovic, a doctoral student at the University of Bern and second author of the study. In addition to the extraneous signals introduced by the spacecraft’s wobble, the faintness of the star in the optical (the range of wavelengths where K2 observes) placed TRAPPIST-1h “near the limit of what we could detect with K2,” he said. To make matters worse, Sestovic said, one transit of the planet coincided with a transit of TRAPPIST-1b, and one coincided with a stellar flare, adding to the difficulty of the observation. “Finding the planet was really encouraging,” Luger said, “since it showed we can still do high-quality science with Kepler despite significant instrumental challenges.”

Luger’s UW co-authors are astronomy doctoral students Ethan Kruse and Brett Morris, post-doctoral researcher Daniel Foreman-Mackey and professor Eric Agol (Guggenheim Fellow). Agol separately helped confirm the approximate mass of TRAPPIST-1 planets with a technique he and colleagues devised called “transit timing variations” that describes planets’ gravitational tugs on one another.

Luger said the TRAPPIST-1 system’s relative nearness “makes it a prime target for follow-up and characterization with current and upcoming telescopes, which may be able to give us information about these planets’ atmospheric composition.”

Contributing to this discovery are researchers at the University of Bern in Switzerland; Paris Diderot and Paris Sorbonne Universities and the CEA Saclay in France; the University of Liège in Belgium; the University of Chicago; the University of California, San Diego; California Institute of Technology; the University of Bordeaux in France; the University of Cambridge in England; NASA’s Ames Research Center, Goddard Space Flight Center, and Johnson Space Center; Massachusetts Institute of Technology; the University of Central Lancashire in England; King Abdulaziz University in Saudi Arabia; Cadi Ayyad University in Morocco; and the University of Geneva in Switzerland.

The research was funded by the NASA Astrobiology Institute via the UW-based Virtual Planetary Laboratory as well as a National Science Foundation Graduate Student Research Fellowship, the Swiss National Science Foundation, the Simons Foundation, the European Research Council and the UK Science and Technology Facilities Council, among other agencies.

 

Happy Anniversary/Birthday Hubble Space Telescope

The portrait features the giant nebula NGC 2014 and its neighbour NGC 2020

It’s 30 years ago to the day that the Hubble telescope was launched – and to celebrate its birthday, the veteran observatory has produced another astonishing image of the cosmos.

This one is of a star-forming region close to our Milky Way Galaxy, about 163,000 light-years from Earth.

The larger object is the nebula NGC 2014; its companion is called NGC 2020.

But astronomers have nicknamed the scene the “Cosmic Reef” because it resembles an undersea world.

Famously blighted by blurred vision at the outset of its mission in 1990, Hubble was eventually repaired and upgraded.

The remarkable pictures it has taken of planets, stars, and galaxies have transformed our view of the cosmos.

It’s still far from retirement.

The US space agency (Nasa), which runs the observatory in partnership with the European Space Agency (Esa), says operations will be funded for as long as they remain productive.

Last year, its data resulted in almost 1,000 scientific papers being published – so it continues to stand at the forefront of discovery.

Frederick, MD Speaker Series brings Dr. Mae Jemison to our area

Dr. Mae Jemison is visiting the Weinberg Center for the Arts on Thursday, February 20, 2020 at 7:30 pm.

Blasting into orbit aboard the Space Shuttle Endeavour is just one of many accomplishments for the dynamic Dr. Mae Jemison, the first woman of color in space. A fierce advocate of a liberal arts education with a natural aptitude toward the sciences, Dr. Jemison addresses a myriad of topics from general motivation to science literacy, to technological and medical innovations, always inserting her sense of humor in each story she tells.

https://weinbergcenter.org/frederick-speaker-series/

December 21, Star Wars: The Rise of Skywalker

Please join fellow STAT members to watch STAR WARS: The Rise of Skywalker at the Senator Theater in Baltimore on Saturday, Dec 21, 12 noon – 5 pm.  We are going to have a table promoting STAT and Shore-Leave.     Please wear either a STAT or SL shirt to support this effort.

Show times:   Star Wars: The Rise of Skywalker 1:15pm 5:00pm 8:50pm

 Senator Theater:  5904 York Rd, Baltimore, MD 21212       http://thesenatortheatre.com/

In Loving Memory, December Passings

We’re saddened to share news of the passing of René Auberjoinois. Auberjoinois was a prolific actor with more than 200 credits to his name, but was perhaps best known as Benson’s Clayton Endicott III and Deep Space Nine’s Constable Odo. In 1993 he was a guest at #ShoreLeave15 and again in 1996 at #ShoreLeave18.

René Auberjoinois passed away on December 8 at the age of 79.

Michael Lamper, musician and husband of Star Trek’s Marina Sirtis, dead at 61

Marina Writes: My beloved husband passed away peacefully in his sleep last night. 

 Lamper was both a guitarist and an Acamarian Gatherer on the episode “The Vengeance Factor”of The Next Generation in the third season.

Star Trek’s D.C. Fontana Dies at 80

By JAMIE LOVETT – December 3, 2019 01:31 pm EST

BornMarch 25, 1939, Sussex, NJ

DiedDecember 2, 2019

Founding Star Trek writer Dorothy Catherine “D.C.” Fontana has died. She was 80 years old and died after a brief illness. Fontana was one of the key writers who worked on Star Trek: The Original Series in the 1960s, helping to bring Gene Roddenberry’s vision to life. She wrote or co-wrote 10 episodes of The Original Series, including “Charlie X,” “Tomorrow is Yesterday,” “The Side of Paradise,” “Friday’s Child,” “Journey to Babel,” “By Any Other Name,” “The Ultimate Computer,” “The Enterprise Incident,” “That Which Survives,” and “The Way to Eden.” She also wrote the episode “Yesteryear” of Star Trek: The Animated Series, worked on five episodes of Star Trek: The Next Generation including its pilot, “Encounter at Farpoint,” as well as “The Naked Now,” “Lonely Among Us,” “Too Short a Season,” and “Heart of Glory,” and co-wrote the teleplay for the Star Trek: Deep Space Nine episode “Dax.”

As a woman working in television in the 1960s, especially in science fiction, Fontana was a trailblazer. She both wrote for and produced Star Trek while being credited as “D.C. Fontana,” keeping her gender a secret until her photograph appeared in Stephen Whitfield’s book The Making of Star Trek in 1968.

Big Bird and Oscar the Grouch puppeteer Caroll Spinney has died

Caroll Edwin Spinney was an American puppeteer, cartoonist, author and speaker most famous for playing Big Bird and Oscar the Grouch on Sesame Street from its inception in 1969 until 2018. Wikipedia

BornDecember 26, 1933, Waltham, MA

DiedDecember 8, 2019, Woodstock, CT

Veteran actor Ron Leibman dies aged 82

Manhattan, New York City, U.S. Ronald Leibman (October 11, 1937 – December 6, 2019) was an American actor. He won both the Tony Award for Best Actor in a Play and the Drama Desk Award for Outstanding Actor in a Play in 1993 for his performance as Roy Cohn in Angels in America.

Born: October 11, 1937, New York

Parents: Grace, Marks, Murray Leibman

Film: Norma Rae, Phar Lap

TV show: Kaz, Archer

Ron Leibman – Wikipedia

https://en.wikipedia.org › wiki › Ron_Leibman

Gone Too Soon

Remembering Aron Eisenberg, 1969-2019

The Nog actor passed away today at age 50.

BY STARTREK.COM STAFF / SEPTEMBER 22, 2019 12:45 AM EDT   

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STARTREK.COM

StarTrek.com is saddened to report the passing of Aron Eisenberg, the beloved actor who portrayed Nog in Star Trek: Deep Space Nine. 

Eisenberg’s wife, Malíssa Longo —  confirmed on Facebook that he passed away today, on September 21, at the age of 50.

Eisenberg, described himself as “actor, filmmaker and proud father” and was a professional photographer who shot landscapes, concerts, corporate photography, portraits and more. Eisenberg’s earliest credits included an episode of the series Straight Up, the TV movie Amityville: The Evil Escapes and the features The Horror Show, Playroom and Beverly Hills Brats, all in the late 1980s.

When he was cast as Nog, the producers told him nothing about the character, nor was he aware of how many episodes he’d be called upon to do. As he told StarTrek.com in a 2012 interview, “I thought every episode I was doing might be my last episode.” Eisenberg ultimately played Nog in more than 40 episodes of DS9. He also portrayed Kar, the young Kazon-Ogla, in the Star Trek: Voyager episode “Initiations.”

https://www.startrek.com/news/aron-eisenberg-obituary-star-trek

Condolences to his family and friends.