This artist’s visualization shows a newly discovered planet-like object named “Sedna” in a location on the outer edge of our known solar system.Credit: NASA/JPL-California Institute of Technology
Use of james webb space telescopeastronomers observed three dwarf planets. kuiper belt, discover light hydrocarbons and complex molecules. These discoveries deepen our understanding of objects in the outer solar system and highlight his JWST’s capabilities in space exploration.
of kuiper beltThe vast region at the edge of the solar system is home to countless icy objects and is a treasure trove of scientific discoveries.detection and characterization of Kuiper belt object (KBO), also called Transsolar system object (TNO), leading to a new understanding of the history of the solar system. The KBO configuration is an indicator of the gravitational currents that have shaped the solar system and reveals the dynamic history of planetary migration. Since the late 20th century, scientists have been eager to closely observe KBO and learn more about its orbit and composition.
Observations with the James Webb Space Telescope
Studying objects in the outer solar system is one of the many goals of the James Webb Space Telescope (JWST). Use of data obtained by Webb’s near infrared spectrometer According to (NIRSpec), an international team of astronomers has observed three dwarf planets in the Kuiper belt. Sedona, Gongon, Quaor. These observations revealed several interesting things about their respective orbitals and compositions, including light hydrocarbons and complex organic molecules that are likely products of methane irradiation.
The research was led by Joshua Emery, a professor of astronomy and planetary science at Northern Arizona University. He was joined by the following researchers: NASAGoddard Space Flight Center (GSFC), Institute of Astrophysics (University of Paris-Saclay), pinhead laboratory, florida space institute (University of Central Florida), lowell observatory, Southwest Research Institute (SwRI), Space Telescope Science Institute (STScI), American University. and Cornell University. A preprint of their paper is available online and is under review for publication. Icarus.
Since Kuiper Belt Object Arrokoth’s last flight, the New Horizons mission has explored objects in the Kuiper Belt and made heliospheric and astrophysical observations. Credit: NASA/JHUAPL/SwRI//Roman Tkachenko
History of Kuiper belt exploration
Despite all the advances in astronomy and robotic spacecraft, what we know about the trans-Neptunian region and the Kuiper belt remains limited.The only mission to research to date Uranus, Neptuneand their main satellite is voyager 2 The mission passed these ice giants in 1986 and 1989, respectively. moreover, new horizons The mission was the first spacecraft to be studied Pluto and its satellite (July 2015), and the only satellite to encounter an object in the Kuiper belt, when it passed the KBO known as Arrokoth on January 1, 2019.
Astronomers’ expectations for JWST
This is one of the many reasons astronomers have been looking forward to JWST’s launch. In addition to studying exoplanets and the universe’s oldest galaxies, its powerful infrared imaging capabilities are also being directed to our own backyards, revealing new images. Mars, Jupiterand that largest satellite. For their research, Emery and his colleagues looked at near-infrared data obtained by Webb about three of his asteroids in the Kuiper belt: Sedna, Gongon, and Kuoar. These objects have a diameter of approximately 1,000 km (620 miles); IAU designation for dwarf planets.
Insights about dwarf planets
These objects are of particular interest to astronomers because of their size, orbit, and composition, Emery told Universe Today via email. Other Solar System objects such as Pluto, Eris, Haumea, and Makemake all retain volatile ice (nitrogen, methane, etc.) on their surfaces. The only exception is Haumea, which (apparently) lost its volatile content due to the large impact. As Emery mentioned, he wanted to see if there were similar volatiles on the surfaces of Sedna, Gonggong, and Quaoar.
“Previous studies have shown that it’s possible. They’re all about the same size, but their orbits are different. Sedna has a perihelion of 76 AU and an aphelion of about 1,000 AU. Gongon is also in a highly elliptical orbit with a perihelion of 33 AU and an aphelion of about 100 AU, and Quaoa is in a relatively circular orbit around 43 AU. The orbits of the planet place the object in different temperature regimes and different illumination environments (for example, Sedna spends most of its time outside the solar heliosphere). We wonder what these different orbits do to the surface. We wanted to see if that had an effect. There are other interesting ices and complex organic materials on the surface.”
Image from one of the two PRISM grid observations of Sedona, Gongong, and Quaoa. Credit: Emery, JP et al. (2023)
Using data from Webb’s NIRSpec instrument, the research team observed all three objects in low-resolution prism mode at wavelengths ranging from 0.7 to 5.2 micrometers (μm), all in the near-infrared spectrum. I have confirmed. Additional observations were made at Quaoar from 0.97 to 3.16 μm using a medium-resolution grating with 10 times the spectral resolution. The resulting spectra revealed some interesting things about these TNOs and their surface composition, Emery said.
“We found abundant ethane (C2H6) in all three objects, but especially in Sedna. Sedna also exhibits acetylene (C2H2) and ethylene (C2H4). Abundances are correlated with orbits ( Sedona is the most abundant, Gongon is the least abundant, and Quaoar is the least abundant), consistent with relative temperature and irradiation environment. These molecules are direct irradiation products of methane (CH4). If ethane (or other If methane (CH4) had been on the surface for a long time, they would have been transformed into more complex molecules by irradiation. We still witness them, so methane (CH4) We believe it must have been resupplied to the surface.”
These findings are consistent with those published in two recent studies led by Lowell Observatory astronomer and NASA collaborator Dr. Will Grundy. new horizons mission and SwRI planetary scientist and geochemist Chris Grein. In both studies, Grundy, Gurian, and their colleagues measured the deuterium/hydrogen (D/H) ratio in methane at Ellis and Makemake and concluded that methane is not primordial. Rather, they argue that this ratio is due to methane being processed internally and delivered to the surface.
“We suspect the same is true for Sedona, Gongong and Quaoa,” Emery said. “We also see that the spectra of Sedona, Gongong, and Kuoar are different from those of the smaller KBO. In two recent conferences, the JWST data of the smaller KBO has been classified into three groups. However, none of the groups were similar to Sedna, Gonggong, and Quaoar. This result is consistent with our three large objects having different geothermal histories. ”
Comparison of the eight largest TNOs with Earth (all to scale).Credit: NASA/Lexicon
What the survey results mean
These discoveries could have significant implications for the study of KBO, TNO, and other objects in the outer solar system. This includes new insights into the formation of objects beyond the frost line in planetary systems, the line at which volatile compounds freeze as solids. In our solar system, the solar Neptune region corresponds to the nitrogen line, where objects retain large amounts of volatile substances with very low freezing points (nitrogen, methane, ammonia, etc.). Emery said these discoveries show what kind of evolutionary processes are at work in the region’s celestial bodies.
“A major implication may be that KBO discovers the size at which the primordial ice became warm enough for internal reprocessing and even differentiation. It could also use these spectra to determine the size of the surface of the outer solar system. We should be able to better understand the ice irradiation process, and future studies could also look more closely at the stability of the volatiles and the atmospheric potential of these objects in all parts of their orbits. Sho.”
The findings demonstrate the capabilities of JWST, which has proven its value time and time again since it became operational early last year. It also reminds us that the Webb not only enables new visions and breakthrough discoveries about distant planets, galaxies, and the large-scale structure of the universe, but also what it can reveal about tiny corners of the universe. I’ll give it to you.
“JWST data is amazing,” Emery added. “Thanks to them, we can now acquire spectra at longer wavelengths than from the ground, making the detection of these ices possible. When observing in new wavelength ranges, the quality of the initial data is considerably lower. JWST not only opened up a new wavelength range, but also provided surprisingly high-quality data sensitive to a range of materials on the surface of the outer Solar System.”
Adapted from an article originally published in today’s universe.
Reference: “A Tale of 3 Dwarf Planets: Ices and Organics on Sedna, Gonggong, and Quaoar from JWST Spectroscopy” JP Emery, I. Wong, R. Brunetto, JC Cook, N. Pinilla-Alonso, JA Stansberry, BJ Holler Authors, WM Grundy, S. Protopapa, AC Souza Feliciano, E. Fernandez Valenzuela, JI Runine, DC Hines, September 26, 2023. Astrophysics > Earth and Planetary Astrophysics.
arXiv:2309.15230
