Tom Jacobs of Bellevue, Washington, loves treasure hunting. Since 2010, the former US Navy officer has been involved in online volunteer projects that allow anyone interested – “citizen scientists” – to peruse the telescope’s data. NASA for signs of exoplanets, planets beyond our solar system.
Now, Jacobs has helped discover a gas giant about 379 light-years from Earth, orbiting a star about the same mass as the Sun. The Jupiter-sized planet is special to astronomers because its 261 days of the year are long compared to many known gas giant planets outside our solar system. The results also show that the planet is only slightly more distant from its star Venus than the Sun. Detect is Published in the Astronomical Journal and was featured at a virtual press event of the American Astronomical Society on January 13.
Exploring this planet and determining its size and mass requires a great deal of collaboration between professional astronomers and citizen scientists like Jacobs. In order to track this planet, they engaged in “a global unifying effort, because we all need to pursue this planet together in order to track this particular planet,” said Paul Dalba, astronomer literature at the University of California, Riverside, and is the lead author of the study book.
“The discovery and publication of TOI-2180 b is a brilliant team effort that demonstrates that professional astronomers and seasoned scientists can work together successfully,” said Jacobs. “It’s synergy at its best.”
How the discovery happened
Newly discovered planet’s signature is hidden in magnetic data NASA’s Transiting Exoplanet Survey Satelliteor TESS. Using TESS data, scientists look for changes in the brightness of nearby stars, which could indicate the presence of orbiting planets.
Jacobs is part of a team of citizen scientists that look at batches of TESS data, which show how a star’s luminosity changes over time, in search of new planets. While professional astronomers use algorithms to automatically scan tens of thousands of data points from stars, these citizen scientists use a program called LcTools, created by Alan R Schmitt created, to check telescope data by eye. That’s why Jacobs’ team, which includes several citizen scientists and two veteran astronomers, calls itself the Imaging Survey Team. Many of them met while working on Planet Hunters, a citizen science project funded by NASA through the Zooniverse that focused on data from NASA’s Kepler spacecraft.
On February 1, 2020, Jacobs came across a graph showing that the starlight from TOI-2180 dimmed by less than half a percent and then returned to its previous brightness level over a 24-hour period, this can be explained by an orbiting planet that is said to be “in transit” as it passes in front of the star from our point of view. By measuring how much light dims as the planet passes, scientists can estimate the planet’s magnitude and, combined with other measurements, its density. But transits can only be seen if a star and its planet are lined up with telescopes looking for them.
The graph showing starlight over time is called a “light curve”. The Imaging Survey Team warned two professional scientist collaborators – Paul Dalba at the University of California, Riverside and Diana Dragomir, assistant professor at the University of New Mexico, that this light curve is likely interesting.
“With this new discovery, we are also pushing the limits of the types of planets we can extract from TESS observations,” said Dragomir. “TESS is not specifically designed to find planets beyond such long orbits, but our team, with the help of citizen scientists, is digging out these rare gems.”
Computer algorithms used by professional astronomers are designed to search for planets by identifying multiple transitions from a single star. That’s why a visual check by citizen scientists is so helpful when there’s only one public transport. Since this is the only instance of TOI-2180 b fuzzy in this dataset, it is called a “unique transit event”.
Tom Jacobs, a citizen scientist who collaborates with professional scientists to search for alien planets, at the Haleakalā Altitude Observatory Site in Hawaii.
“The manual effort they put in is really important and really impressive, because it’s really hard to write code that can go through millions of slight curves and reliably identify single carrier events. trust,” Dalba said. “This is an area where humans are still coding.”
But how can the team rule out other explanations for the brief immersion in starlight? Can they be sure they have found a planet? They will need follow-up observations.
Fortunately, Dalba was able to recruit the Automated Planet Search Telescope at the Lick Observatory in California. “I use that telescope to measure the oscillation of the star, then determine how massive the planet is, if it’s a planet,” he said. The team also used the Keck I telescope at the WM Keck Observatory in Hawaii to make some of these measurements when the Lick Observatory was threatened by wildfires.
With 27 hours of observations over 500 days, Dalba and colleagues observed the planet’s gravitational pull on the star, allowing them to calculate the planet’s mass and estimate a range of possibilities for its orbit. its. However, they still want to observe the movement of the planet when it returns to confirm its orbit. Unfortunately, finding a second transit will be difficult because there is so much uncertainty about when the planet will face its star again.
Dalba went ahead and organized an observation campaign involving both professional astronomers and citizen scientists using the telescope at 14 sites on three continents in August 2020. To support As part of the campaign, Dalba camped for five nights in California’s Joshua Tree National Park and sought transportation with two hand-held amateur telescopes. The collaborative effort yielded 55 datasets over 11 days.
In the end, none of these telescopes detected the planet with confidence. However, the lack of a clear detection for this time period has set boundaries on how long the orbit could be, suggesting a period of about 261 days. Using that estimate, they predict TESS will see the planet transit its star again in February 2022.
About the planet
TOI-2180 b is almost 3 times the mass of Jupiter but has the same diameter, which means it is denser than Jupiter. This makes scientists wonder if it formed in a different way than Jupiter.
Another clue to the planet’s formation may be what’s inside it. Through computer models, they determined that the new planet could have 105 Earth masses of elements heavier than hydrogen and helium. “That’s a lot,” Dalba said. “It’s more than what we suspected was inside Jupiter.”
Astronomers still have a lot to learn about the range of planets out there. About 4,800 exoplanets have been confirmed, but there are billions of planets in our galaxy. The new discovery indicates that among the giant planets, some have more heavier elements than others.
In our solar system, the giant Jupiter orbits the Sun every 12 years; for Saturn, “year” is 29 years. We don’t have giant planets like TOI-2180 b between the Earth and the Sun. But outside the solar system, astronomers have found dozens of exoplanets that are larger than Jupiter and orbit much closer to their stars, even closer than Mercury’s.
With an average temperature of about 170 degrees Fahrenheit, TOI-2180 b is warmer than room temperature on Earth and warmer than planets outside our solar system including Jupiter and Saturn. But compared with the sequence of giant transiting planets that astronomers have found orbiting other stars, TOI-2180 b is unusually cold.
“It’s a great stepping stone between most of the giant planets we’ve found, and then the really cold Jupiter and Saturn,” says Dalba.
What’s next?
When TESS re-observed the star in February, Dalba and the citizen scientists were eager to take the data and delve into the study again. If they find the signature of the planet, confirming a 261-day period, that will give more meaning to the data from their global campaign to find it in 2020.
NASA’s James Webb Space Telescope, launched on December 25, is capable of observing the planet and its atmosphere. But there was another reason Dalba was excited about Webb’s abilities. Given that in our solar system Jupiter has rings and moons, Webb can be used to look for the presence of small objects orbiting TOI-2180 b.
So far, no rings or moons have been found outside our solar system with certainty, but one possible reason is that many exoplanets have been found very close to their stars, whose gravity can pull those objects away. TOI-2180 b, which is more distant from its host star, could present an interesting opportunity for such a search. “I think this is an interesting system for that later in the future,” Dalba said.
When he’s not pursuing his planet-hunting hobby, Jacobs, the citizen scientist, works with nonprofits to help people with disabilities find work in their communities.
Members of the Image Survey Team “spend many hours each day surveying data for the pure pleasure and excitement of advancing science,” says Jacobs. Collectively, the team has co-authored more than 68 peer-reviewed scientific papers, including the discovery of the transition of “exoplanets,” or comets outside the solar system, across the surface of a star. star.
“We love to contribute to science,” says Jacobs. “And I love this kind of survey, knowing that a survey is in new uncharted territory that has never been seen by humans before.”
Learn more about Citizen Science
NASA has many citizen science collaborations on topics ranging from Earth and Sun science to the wider universe. Anyone in the world can participate. Check out the latest opportunities at Science.nasa.gov/citizenscience.
About TESS
TESS is a NASA Astrophysical Exploration mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA’s Goddard Space Flight Center. Other partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts; MIT’s Lincoln Laboratory; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are part of the mission.
The National Science Foundation’s Postdoctoral Fellowship Program in Astrophysics and Astrophysics has contributed support to this research.
Related
