Managed by NASA’s Jet Propulsion Laboratory through launch, Webb’s Mid-Infrared Instrument (MIRI) recently unveiled a significant discovery. Scientists were astonished when NASA’s James Webb Space Telescope focused on a group of young stars known as WL 20. Despite being studied since the 1970s with at least five other telescopes, it was Webb’s unparalleled resolution and specialized instruments that revealed WL 20S to be a binary star system, formed about 2 million to 4 million years ago.
This discovery, using Webb’s MIRI, was announced at the 244th meeting of the American Astronomical Society on June 12. MIRI not only identified the twin stars but also detected matching jets of gas streaming from their north and south poles. “Our jaws dropped,” said Mary Barsony, lead author of the study. “We thought we knew this source well, but MIRI’s capabilities showed us otherwise. It’s like having brand new eyes.”
Further observations by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile revealed disks of dust and gas around both stars, suggesting possible planet formation. These findings indicate the stars are transitioning from their early developmental stage, offering scientists a rare chance to study their evolution into maturity.
“The power of these two telescopes together is really incredible,” said Mike Ressler, MIRI project scientist at NASA’s Jet Propulsion Laboratory and co-author of the study. “Seeing these as two stars instead of one changes our interpretation of the ALMA data, which now shows two distinct disks. This provides new insights into the stars’ critical developmental phase.”
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| This artist’s concept depicts two young stars nearing the end of their formation, encircled by gas and dust disks from which planets may form, with jets of gas shooting from their poles. |
Stellar Jets : A Star-Forming Region Revealed by Webb.
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| This image of the WL 20 star group combines ALMA and Webb’s MIRI data, showing blue and green gas jets from twin stars’ poles and pink disks of dust and gas surrounding them. |
WL 20 resides in a much larger, well-studied star-forming region of the Milky Way galaxy called Rho Ophiuchi. This massive cloud of gas and dust, about 400 light-years from Earth, obscures the view of the stars within at visible wavelengths. However, the James Webb Space Telescope (Webb) with its infrared capabilities can pierce through these dusty veils.
Webb’s Mid-Infrared Instrument (MIRI) detects the longest infrared wavelengths of any instrument on the telescope. This allows it to peer into obscured regions like WL 20, revealing details that were previously hidden. While radio waves can also penetrate dust, they don’t always provide the same level of detail as infrared light.
The key to unlocking the true nature of WL 20 came from the combination of Webb’s observations and those from another powerful instrument, the Atacama Large Millimeter/submillimeter Array (ALMA). ALMA observed the disks of gas and dust surrounding the stars in WL 20S emitting light in the submillimeter range, which also penetrates the dust clouds. However, these observations could have been misinterpreted as a single disk with a gap.
Here’s where MIRI played a crucial role. The stellar jets emanating from the stars, composed of charged particles, radiate in mid-infrared wavelengths detectable by MIRI but not at submillimeter wavelengths observed by ALMA. Only an instrument with MIRI’s combined spatial and spectral resolution could definitively reveal these jets, providing the crucial evidence that WL 20S is actually a binary star system.
ALMA Observations and Stellar Formation Phases.
ALMA (Atacama Large Millimeter/submillimeter Array) plays a crucial role in our understanding of star formation. By observing clouds of leftover material around young stars, ALMA provides insights into their evolution. These clouds, composed of whole molecules like carbon monoxide, emit light at longer wavelengths. Interestingly, ALMA’s observations reveal the absence of such clouds, indicating that the stars have progressed beyond their initial formation phase. The scientific community eagerly awaits further revelations from the James Webb Space Telescope (Webb), which promises to unlock more secrets about the life cycle of stars.
Webb, an international collaboration led by NASA, ESA, and CSA, is poised to explore our solar system, distant exoplanets, and the enigmatic structures of the universe. The Mid-Infrared Instrument (MIRI), developed through a partnership between NASA and ESA, will be a key player in this cosmic exploration. George Rieke (University of Arizona) leads the MIRI science team, while Gillian Wright oversees the European contributions. The MIRI cryocooler development involved collaboration between JPL, Northrop Grumman, and NASA’s Goddard Space Flight Center.
