Tag Archives: Protostar

ALMA Discovers Heavy Water in Planet-Forming Disk Surrounding Distant Protostar

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An astronomer utilizing the Atacama Large Millimeter/Submillimeter Array (ALMA) has discovered double deuterated water (D2O), commonly known as “heavy water,” in the protoplanetary disk surrounding the protostar V883 Orionis, situated 1,300 light-years away in the Orion constellation. This finding indicates that some of the water found in comets—and even on Earth—might predate the stars themselves, offering transformative insights into the history of water in our solar system.

This artist’s impression illustrates the evolution of heavy water molecules, previously detected in giant molecular clouds, planet-forming disks, and comets, before ultimately reaching Earth. Image credit: NSF / AUI / NRAO of NSF / P. Vosteen / B. Saxton.

Investigating the primordial material from the protoplanetary disk that gave rise to our solar system suggests that water may have been transported to Earth via comet or asteroid impacts.

However, it remains uncertain whether the water ice present on these celestial objects formed primarily during the protoplanetary disk phase or if it is considerably older, originating from parent molecular clouds.

“This detection clearly demonstrates that the water found in the planet-forming disk around V883 Orionis predates the central star and must have formed during the early phases of star and planet formation,” stated Dr. Margot Rehmker, an astronomer at the University of Milan.

“This marks a significant leap in our understanding of the journey of water throughout planet formation and how this water potentially reached the solar system, including Earth, through similar mechanisms.”

The chemical fingerprinting of heavy water indicates that these molecules have withstood the turbulent processes of star and planet formation, traversing billions of kilometers through the cosmos and ending up in planetary systems like ours.

Rather than being completely destroyed and reformed within the disk, a significant portion of this water is inherited from the earliest, most frigid stages of star formation, serving as a cosmic remnant that may still exist on Earth today.

“Until now, it was uncertain whether most of the water in comets and planets was newly formed in young disks such as Orionis V883 or whether it was ‘pure’ from ancient interstellar clouds,” remarked Dr. John Tobin, an astronomer at the NSF National Radio Astronomy Observatory.

“The detection of heavy water using sensitive isotopic isomer ratios (D2oh2O) validates that this water is an ancient relic, forming a crucial link between clouds, disks, comets, and planets.”

“This finding is the first direct evidence that water can traverse through stars unaltered and intact, moving from clouds to the materials that constitute planetary systems.”

The team’s paper is published in this week’s edition of Nature Astronomy.

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M. Riemker et al. Primitive ice within a planet-forming disk identified by heavy water. Nat Astron published online October 15, 2025. doi: 10.1038/s41550-025-02663-y

Source: www.sci.news

Webb finds hourglass-shaped molecular cloud surrounding protostar

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Astronomers MIRI (mid-infrared measuring instrument) camera The NASA/ESA/CSA James Webb Space Telescope probe has captured striking new photos of molecular cloud L1527.

L1527, shown in this image from Webb's MIRI instrument, is a molecular cloud enveloping the IRAS 04368+2557 protostar. The more diffuse blue light and filamentary structures in the image come from organic compounds called polycyclic aromatic hydrocarbons (PAHs), while the red in the center of the image is a thick layer of energetic gas and dust that surrounds the protostar. The white intermediate regions are a mix of PAHs, ionized gases, and other molecules. Image courtesy of NASA / ESA / CSA / STScI.

L1527, also known as LDN 1527, is located about 447 light-years from Earth in the constellation Taurus.

The young protostar, called IRAS 04368+2557, is embedded in a molecular cloud that is part of a star-forming region in the constellation Taurus.

IRAS 04368+2557 is a relatively young star, only 100,000 years old.

Given its age and brightness in the far-infrared, the star is likely a class 0 protostar, the earliest stage of star formation.

IRAS 04368+2557 has an edge-on disc with two misaligned parts.

The inner and outer parts of the disk have slightly different orbital planes and are connected at 40 to 60 AU (astronomical units) from the protostar, but the disk is point-symmetric with respect to the location of the protostar.

Webb's previous observations of L1527 showed that NIRCam (Near Infrared Camera)Astronomers were able to peer into the region, where the molecular cloud and protostar appeared in opaque, vibrant colors.

Both NIRCam and MIRI show the effects of outflows that shoot out in opposite directions along the protostar's rotation axis as the protostar consumes gas and dust from the surrounding cloud.

These outflows take the form of bow shock waves relative to the surrounding molecular cloud and appear as filament-like structures throughout the molecular cloud.

They also energize, or excite, the material around them, causing the areas above and below them to glow, imprinting bright hourglass structures in the molecular cloud.

“But unlike NIRCam, which primarily images light reflected from dust, MIRI will be able to probe how these outflows affect the thickest dust and gas in the region,” astronomer Webb said in a statement.

“The blue region that takes up most of the hourglass represents carbonaceous molecules called polycyclic aromatic hydrocarbons.”

“The IRAS 04368+2557 protostar itself is shown in red, along with the dense mixture of dust and gas that surrounds it.”

“Meanwhile, MIRI revealed white regions just above and below the protostar, which are not as clearly visible in the NIRCam view.”

“This region is a mixture of hydrocarbons, ionized neon, and thick dust, indicating that the protostar is consuming material from the disk in a promiscuous manner, pushing this material over great distances.”

“As IRAS 04368+2557 continues to age and emits energetic jets, it will consume, destroy or push aside much of this molecular cloud, and much of the structure seen here will begin to disappear.”

“Eventually, when the accumulation of mass stops, this impressive spectacle will come to an end and the star itself will become more clearly visible to optical telescopes.”

“Combining both near-infrared and mid-infrared analyses will shed light on the overall behavior of this system, including how the central protostar is influencing the surrounding region.”

“Other stars in Taurus, the star-forming region in which L1527 resides, may form in exactly this way, which could lead to the disruption of other molecular clouds, either preventing the formation of new stars or promoting their development.”

Source: www.sci.news

Hubble Space Telescope Discovers a Massive Binary Protostar within the RCW 7 Nebula

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RCW 7 is located in the constellation Puppis, about 5,300 light years from Earth.

This Hubble image shows the nebula RCW 7. Image courtesy of NASA/ESA/Hubble/J. Tan, Chalmers University, University of Virginia.

“Nebulae are regions of space that are rich in the raw materials needed to form new stars,” the Hubble astronomers said.

“Due to the effects of gravity, some of these molecular clouds collapse and merge into protostars surrounded by a rotating disk of remaining gas and dust.”

“In the case of RCW 7, the protostar forming here is particularly massive, emitting intense ionizing radiation and a powerful stellar wind that propelled the star into a “H II region“.

“The H II regions are filled with hydrogen ions. HI refers to regular hydrogen atoms, and H II is hydrogen that has lost an electron.”

“Ultraviolet rays from the massive protostar excite the hydrogen, which then emits light that gives the nebula its soft pink glow.”

In RCW 7, the researchers IRAS 07299-1651.

“IRAS 07299-1651 still resides within a cocoon of glowing gas, in clouds swirling towards the top of the nebula,” the researchers said.

To expose this star and its sibling, the new image was created from separate exposures taken in the near-infrared region of the spectrum. Hubble’s Wide Field Camera 3 (WFC3).

“This massive protostar is most bright in ultraviolet light, but it also emits a lot of infrared light that penetrates much of the surrounding gas and dust and can be seen by the Hubble Telescope,” the scientists said.

“Many of the other large visible stars in this image are not part of the nebula, but are located between the nebula and the solar system.”

Assuming a circular orbit, IRAS 07299-1651 is estimated to have a minimum total mass of 18 times that of the Sun and a maximum period of 570 years.

“The formation of the H II region marks the beginning of the end of the molecular cloud,” the authors said.

“Over just a few million years, radiation and winds from the massive stars gradually disperse the gas, and this dispersion continues as the most massive stars end their lives in supernova explosions.”

“Only a small portion of this gas will be absorbed by new stars within the nebula, while the rest will spread throughout the galaxy and eventually form new molecular clouds.”

Team Investigation result Published in a journal Natural Astronomy.

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Y. Chan others2024. Dynamics of a giant binary star at birth. Nat Astron 3, 517-523; doi: 10.1038/s41550-019-0718-y

Source: www.sci.news