A new object circling a Sun-like star that had been missed by prior searches has been identified by citizen scientists. The object is thought to be a big planet or a small brown dwarf, a type of object that is not massive enough to burn hydrogen like genuine stars, and is more than 1,600 times further away from its host star than the Earth is from the Sun. The Astrophysical Journal will publish details on the new world on December 9, 2021.
“This star had been looked at by more than one campaign searching for exoplanet companions. But previous teams looked really tight, really close to the star,” said lead author Jackie Faherty, senior scientist in the American Museum of Natural History’s Department of Astrophysics and co-founder of the citizen science project Backyard Worlds: Planet 9, which led to the object’s discovery.
“Because citizen scientists really liked the project, they found an object that many of these direct imaging surveys would have loved to have found, but they didn’t look far enough away from its host.”
Volunteers can scan over five years of digital photos from NASA’s Wide-field Infrared Survey Explorer (WISE) mission to find new worlds both inside and outside our solar system as part of the Backyard Worlds initiative.
If an object close to Earth is moving, it will appear to “jump” in the same spot in the sky over time, much like a flipbook item. Users can then mark these objects as being worth further investigation by scientists.
Jörg Schümann, a Backyard Worlds participant from Germany, notified scientists to a new co-moving system in 2018, describing an object that appeared to be traveling with a star. Scientists utilized telescopes in California and Hawaii to observe the star and object separately after establishing the system’s motion, and they were ecstatic with what they found.
This star had been looked at by more than one campaign searching for exoplanet companions. But previous teams looked really tight, really close to the star. Because citizen scientists really liked the project, they found an object that many of these direct imaging surveys would have loved to have found, but they didn’t look far enough away from its host.
Jackie Faherty
The new object is young and has a low mass, ranging from 10 to 20 times Jupiter’s mass. This range intersects with a critical cutoff point of 13 times Jupiter’s mass, which is frequently used to separate planets from brown dwarfs.
However, scientists are still unsure how heavy planets can be, making reliance on this threshold difficult.
“We don’t have a very good definition of the word ‘planet,’” said Faherty.
Another distinguishing trait is how they develop: planets form when material gathers in disks around stars, whereas brown dwarfs form when enormous clouds of gas collapse, much like stars do. However, the physical features of this new item offer no clues as to how it came to be.
“There are hints that maybe it’s more like an exoplanet, but there’s nothing conclusive yet. However, it is an outlier,” said Faherty.
The new object’s relationship to its host star astonished the researchers the most. The object is 1,600 times farther away from the star than the Earth is from the Sun, which is due to its comparatively low mass.
Few objects with masses that far distant from their host star have been discovered. In the end, this discovery may aid scientists in better understanding how solar systems form, which is critical to comprehending the origins of life in the cosmos.
“You had an exoplanet community just staring so close to it,” said Faherty. “And we just pulled out a little, and we found an object. That makes me excited about what we might be missing in giant planets that might exist around these stars,” said Faherty. “Sometimes, you need to broaden your scope.”
Other authors on the study include Johanna M. Vos, Daniella C. Bardalez Gagliuffi, Austin Rothermich, and Andrew Ayala from the American Museum of Natural History; Jonathan Gagné from the University of Montreal; Mark Popinchalk from the American Museum of Natural History and the City University of New York; Adam J. Burgasser, Christian Aganze, Chih-Chun Hsu, Roman Gerasimov, and Christopher A. Theissen from the University of California, San Diego; Adam C. Schneider from the U.S. Naval Observatory and George Mason University; J. Davy Kirkpatrick and Federico Marocco from the California Institute of Technology; Aaron M. Meisner from NSF’s National Optical-Infrared Astronomy Research Laboratory; Marc J. Kuchner from NASA Goddard Space Flight Center; Dan Caselden from Gigamon Applied Threat Research; Eileen C. Gonzales from Cornell University; Sarah L. Casewell from the University of Leicester; John H. Debes from the Space Telescope Science Institute; William J. Cooper from the University of Hertfordshire and the National Institute for Astrophysics in Italy, and R. L. Smart from the National Institute for Astrophysics in Italy.
This research was supported in part by NASA Astrophysics Data Analysis Program grant #s NNH17AE75I and 80NSSC20K0452 as well as NASA grant 2017-ADAP17-0067, the National Science Foundation grant #s 2007068, 2009136, and 2009177, and the Heising-Simons Foundation.
