In 2008, observations from NASA’s now-retired Spitzer infrared space telescope hinted on the presence of neon throughout the protoplanetary disk of Sun-like star SZ Chamaeleontis (SZ Cha). Nonetheless, Spitzer’s instruments couldn’t confirm whether this reading was correct. Over a decade after Spitzer’s results were published, the joint NASA, European Space Agency, and Canadian Space Agency James Webb Space Telescope observed SZ Cha and directly detected distinct amounts of neon within the protoplanetary disk of SZ Cha — confirming Spitzer’s observations from 2008.
Webb’s observations, coupled with Spitzer’s data from 2008, are allowing scientists to higher understand SZ Cha and its future as a star system while also providing scientists with insight into what our own solar system could have looked like during its formation.
“How did we get here? It really goes back to that big query, and SZ Cha is similar style of young star, a T-Tauri star, as our Sun was 4.5 billion years ago on the dawn of the solar system. The raw materials for Earth, and eventually life, were present within the disk of fabric that surrounded the Sun after it formed, and so studying these other young systems is as close as we are able to get to going back in time to see how our own story began,” said lead creator Catherine Espaillat of Boston University in Massachusetts, who also led the 2008 Spitzer observations.
Small differences in the precise kinds of neon detected by Spitzer and Webb have revealed a change in high-energy radiation throughout the disk — a never-before-observed phenomenon. This alteration in high-energy radiation is predicted to eventually cause the protoplanetary disk around SZ Cha to evaporate, limiting the full period of time planets must form throughout the disk. Neon is an awesome indicator of how much radiation is hitting and eroding the protoplanetary disk around a star, which is why many scientists seek for neon around young stars.
15 years ago, Spitzer saw unusual readings of neon III in a still-developing “solar system.” Webb just discovered the abnormal neon III has all but disappeared. Scientists imagine clues to our own solar system’s past may lie in these flashing neon signs: https://t.co/HfHMRONG8N pic.twitter.com/Qpk2JSPh6V
— NASA Webb Telescope (@NASAWebb) November 15, 2023
Spitzer’s observations hinted on the presence of neon III inside SZ Cha’s protoplanetary disk — an especially rare neon reading that is unusual in other young T-Tauri star disks, specifically protoplanetary disks which are repeatedly exposed to high-energy X-rays. The presence of neon III implies that the aforementioned high-energy radiation inside SZ Cha’s disk was being produced by ultraviolet (UV) light somewhat than the more common X-ray light. It was the one detection of neon III in a sample of fifty to 60 stellar protoplanetary disks, making the difference in UV light and X-rays much more significant for the planets inside SZ Cha’s disk and the lifetime of the disk as a complete.
“Planets are essentially in a race against time to form up within the disk before it evaporates. In computer models of developing systems, extreme ultraviolet radiation allows for 1 million more years of planet formation than if the evaporation is predominately attributable to X-rays,” said co-author Thanawuth Thanathibodee of Boston University.
Nonetheless, when Espaillat et al. returned to SZ Cha and its protoplanetary disk with Webb, they found that the neon III signature detected by Spitzer wasn’t there — likely meaning that the neon III inside SZ Cha’s protoplanetary disk had entirely disappeared. The disappearance of the neon III from the disk was probably resulting from the dominance of X-ray radiation throughout the disk — a typical occurrence inside all these protoplanetary disks.
More specifically, the team believes that different neon signatures inside SZ Cha’s disk create a variable wind that, when present throughout the disk, causes UV light to be absorbed — meaning only X-rays are left behind to pummel the disk when the UV light is absorbed. Some of these winds will not be unusual in newly forming star systems with energetic stars at their core, but occasionally, there may be a quiet period where the winds don’t exist within the disk. This quiet period is what allowed for the presence of neon III within the disk when Spitzer observed SZ Cha in 2008.
![](https://www.nasaspaceflight.com/wp-content/uploads/2023/11/stsci-01heqmgyyqfbmttv4m0g41p7wp-scaled.webp)
Data from Webb and Spitzer’s observations of SZ Cha. Note the absence of neon III in Webb’s observations. (Credit: NASA, ESA, CSA, Ralf Crawford (STScI))
“Each the Spitzer and Webb data are excellent, so we knew this needed to be something latest we were observing within the SZ Cha system – a big change in conditions in only 15 years,” explained co-author Ardjan Sturm of Leiden University, Leiden, Netherlands.
Discovering the variable wind and the disappearance of neon III from the system were just two of the numerous mysteries of SZ Cha, and even following their discoveries Espsillat et al. still have many questions. The team is already planning to make use of Webb to look at SZ Cha again, in addition to with other telescopes.
“It’s going to be vital to check SZ Cha, and other young systems, in multiple wavelengths of sunshine, like X-ray and visual light, to find the true nature of this variability we’ve found. It’s possible that temporary, quiet periods dominated by extreme UV radiation are common in lots of young planetary systems, but we just haven’t been capable of catch them,” said co-author Caeley Pittman of Boston University.
Webb and Spitzer’s observations proceed to indicate how useful infrared telescopes are for locating and investigating various objects and phenomena within the universe. Without observations just like the SZ Cha observations, scientists wouldn’t have known concerning the variable wind and the way it affects neon and other elements inside a young T-Tauri star’s protoplanetary disk.
“Once more, the universe is showing us that none of its methods are so simple as we would prefer to make them. We want to rethink, re-observe, and gather more information. We’ll be following the neon signs,” Espaillat explained.
Espaillat et al.’s research was published in journal on Nov. 15.