IREx Researchers Contribute to Stunning New Webb Observations of Star-Forming Cluster in Perseus

Researchers at the Trottier Institute for Research on Exoplanets (IREx) are celebrating their contribution to a new study of NGC 1333 from the NASA/ESA/CSA James Webb Space Telescope (JWST). The mosaic image seen in the upper right reveals the nearby star-forming cluster in unprecedented detail, located within the Perseus molecular cloud approximately 960 light-years from Earth. Among the groundbreaking findings are newly born, free-floating brown dwarfs—objects with masses comparable to giant planets.

Three IREx scientists—Loïc Albert, René Doyon, and David Lafrenière—played key roles in this research, contributing their expertise to the acquisition and analysis of the data. The first findings from this deep spectroscopic survey of NGC 1333 have been accepted for publication in the Astrophysical Journal, highlighting the identification of brown dwarfs down to planetary masses.

In addition to the spectacular mosaic image, the team also conducted a deep spectroscopic survey of NGC 1333 using Webb’s Near-InfraRed Imager and Slitless Spectrograph (NIRISS), a key instrument developed in Canada. This survey has uncovered important insights into how stars and planets form by observing free-floating planetary-mass objects (FFPMOs). Using NIRISS’ powerful Wide Field Slitless Spectroscopy (WFSS), the study identified six new low-mass brown dwarf candidates with masses between 5 and 15 times that of Jupiter. One object, with an estimated mass of only 5 Jupiter masses, shows evidence of a disk—making it a unique find as the smallest mass object observed to have a disk! This survey highlights NIRISS’ remarkable sensitivity to some of the smallest objects formed like stars, offering a deeper understanding of the early stages of star and planetary formation.

“This work showcases the formidable power of NIRISS’ slitless spectroscopy mode, revealing compelling targets such as these candidate planetary-mass objects,” said René Doyon, Principal Investigator of Webb’s Canadian instrument, NIRISS.

David Lafrenière added, “It’s very exciting to be able to detect these newly-formed, isolated objects that are just a few times more massive than Jupiter. They are the very smallest objects that nature can produce in the same manner as stars, and studying them will help us immensely in figuring out the details of the star-formation process itself and how it relates to the formation of planets.”

Loïc Albert emphasized the importance of this study for future work: “A big open question is to determine if small star formation nurseries are more or less prolific at forming brown dwarfs than are large nurseries? This study with NIRISS was successful in counting the number of ‘baby’ brown dwarfs recently formed in the small nursery that is NGC 1333. It now serves as a precious reference for upcoming studies being carried with JWST counting brown dwarfs, this time, in large star formation nurseries.”

The newly captured images provide insights into a region that Hubble Space Telescope previously imaged in 2023 to celebrate its 33rd anniversary. While Hubble’s observations were limited due to dust clouds, Webb’s larger aperture and infrared capabilities allowed it to pierce through the dusty veil. This revealed newborn stars, brown dwarfs, and planetary-mass objects, as well as gas glowing in infrared, forming Herbig-Haro objects—markers of active star formation.

The NGC 1333 mosaic also offers a unique opportunity to study stellar nurseries akin to the environment where our own Sun and planetary system formed 4.6 billion years ago. The cluster, only 1-3 million years old, provides a snapshot of stars like our Sun, brown dwarfs, and free-floating planets in their nascent stages.

The observations were part of Webb’s Guaranteed Time Observation programme 1202 (PI: A. Scholz) and represent a significant step forward in our understanding of star formation.

To check out the image of NGC 1333 in higher resolution, head over to ESA’s site!

IREx Science Contacts:

Scientific Contacts

René Doyon (Email)

Loïc Albert (Email)

David Lafrenière (Email)

IREx Media Contact:

Heidi White (Email)

Canadian Outreach Scientist for the James Webb Space Telescope