Dark Energy Camera Captures Sparse Pockets of Light Amongst Dark Clouds of Chamaeleon I

PR Image noirlab2519a
The Ominous Chamaeleon I Dark Cloud

---

Videos


PR Video noirlab2519a
Pan on the Chamaeleon I Dark Cloud


PR Video noirlab2519b
Zooming into the Chamaeleon I Dark Cloud


PR Video noirlab2519c

Cosmoview Episode 99: Dark Energy Camera Captures Sparse Pockets of Light Amongst Dark Clouds of Chamaeleon I (horizontal)

PR Video noirlab2519d

Cosmoview Episode 99: Dark Energy Camera Captures Sparse Pockets of Light Amongst Dark Clouds of Chamaeleon I (vertical)

  

PR Video noirlab2519e

Episodio 99 de Cosmoview: Cerro Tololo descubre pequeñas fuentes de luz dispersas entre una densa nube molecular cercana a la Tierra (horizontal) in English only

 

  

PR Video noirlab2519f

Episodio 99 de Cosmoview: Cerro Tololo descubre pequeñas fuentes de luz dispersas entre una densa nube molecular cercana a la Tierra (vertical)

---

From within the inky black plumes of the Chamaeleon I dark cloud, the light from three reflection nebulae breaks through

The ominous Chamaeleon I dark cloud, the nearest star-forming region to Earth, is captured in this image taken with the 570-megapixel Department of Energy-fabricated Dark Energy Camera mounted on the U.S. National Science Foundation Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory, a Program of NSF NOIRLab. Chamaeleon I is one portion of the larger Chamaeleon Complex and is home to three reflection nebulae that are brightly illuminated by nearby newly formed stars.

The origin of our Sun, and all the planets, comets and asteroids that orbit it, can be traced back to their birthplace inside a massive cloud of cold gas and dust, not unlike the billowing molecular cloud featured in this image. Found within these cool regions of highly condensed interstellar material are stellar nurseries where young stars are emerging from the swirling gaseous plumes. These regions are also home to nebulae that shine bright with the reflected light of newly formed stars.

This image was captured with the 570-megapixel Department of Energy-fabricated Dark Energy Camera (DECam) mounted on the U.S. National Science Foundation Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory, a Program of NSF NOIRLab. It showcases the atramentous molecular cloud known as the Chamaeleon I dark cloud. Located about 500 light-years away, Chamaeleon I is the nearest active star-forming region to Earth. This dark cloud is estimated to be around two billion years old and is home to about 200–300 stars.

Chamaeleon I is just a small component of the larger Chamaeleon Complex, an enormous active stellar birthplace that occupies almost the entirety of the southern constellation Chamaeleon, even overlapping into Apus, Musca, Carina and Octans. The Chamaeleon Complex also includes the Chamaeleon II and Chamaeleon III dark clouds, which show little and no active star formation, respectively.

Near the center of this image, brightly glowing from within the thick cosmic dust, is one of Chamaeleon I’s notable features, the stunning reflection nebula Cederblad 111. Reflection nebulae are clouds of gas and dust that do not create their own light, but instead shine by reflecting the light from nearby stars. This happens in the surroundings of newly formed stars that are not hot enough to excite the hydrogen atoms of the cloud, as is the case for emission nebulae. Instead, their light bounces off of the particles within the cloud.

Cederblad 110, a second reflection nebula within Chamaeleon I, can be seen just above Cederblad 111 with its recognizable C-shape. Like Cederblad 111, Cederblad 110 lies close to an active low-mass star forming region where the light of young stars is scattered by the nebula’s dust particles. This reflection creates a bright pocket of light amongst the otherwise opaque clouds.

Below the pair of reflection nebulae is the orange-tinted Chamaeleon Infrared Nebula. Resembling the wings of an ethereal cosmic aviator, this nebula is the product of streams of fast-moving gas that are being ejected from a newly formed low-mass star at the core of the nebula. These streams have carved a tunnel through the interstellar cloud where the young star was born. The infrared and visible light emitted by the nascent star escapes along this tunnel and scatters off its walls, giving rise to the wispy reflection nebula.

Embedded throughout Chamaeleon I, astronomers have also found numerous Herbig-Haro objects — bright patches of nebulosity that form when ionized jets of gas ejected from newly born stars collide with slow-moving gas in the surrounding cloud. One of these objects can be spotted as a tiny, faint red patch lying in the dusty realm between Cederblad 111 and Cederblad 110

More information

NSF NOIRLab, the U.S. National Science Foundation center for ground-based optical-infrared astronomy, operates the International Gemini Observatory(a facility of NSF,NRC–Canada,ANID–Chile, MCTIC–Brazil,;MINCyT–Argentina, andKASI–Republic of Korea), NSF Kitt Peak National Observatory (KPNO), NSF Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and NSF–DOE Vera C. Rubin Observatory (in cooperation withDOE’SLACNational Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona.

The scientific community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence of I’oligam Du’ag to the Tohono O’odham Nation, and Maunakea to the Kanaka Maoli (Native Hawaiians) community.

The Dark Energy Camera was designed specifically for DES. It was funded by the Department of Energy (DOE) and was built and tested at DOE's Fermilab.

Source: NSF’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab)/News

---

Links

• Explore the Chamaeleon I dark cloud in more detail
• Photos of the Víctor M. Blanco 4-meter Telescope
• Videos of the Víctor M. Blanco 4-meter Telescope
• Photos of DECam
• Images taken by DECam
• Check out other NOIRLab Photo Releases

---

Contacts

Josie Fenske
Public Information Officer
NSF NOIRLab
Email: josie.fenske@noirlab.edu

---

JWST sheds Light on the Structure of interstellar Water Ice

Illustration of the various OH bonding scenarios observed in the dark cloud Cha I with JWST. Three spectral features corresponding to three OH bonding environments are revealed in spectra along lines of sight towards Cha I. In the interstellar icy dust grain represented here, each OH bonding environment is represented by a “cutout” in the ice and its corresponding spectral absorption feature indicated. Environment one (right hand side) corresponds to OH stretches of H2O molecules fully bound to neighbouring H2O molecules in the ice, predominantly responsible for the intense H2O absorption feature at ∼3 μm. Environments two (left hand side) and three (centre) correspond to OH stretches of H2O molecules not fully bound to neighbouring water molecules i.e. dangling OH. Environment two (left hand side) illustrates dangling OH in a predominantly water ice environment, but not fully bound to the surrounding water molecules (2.703 μm), while environment three (centre) illustrates dangling OH in interaction with other molecular species in the ice (2.753 μm). This cartoon is intended to be illustrative of the various possible ice environments that contribute to the observed dangling OH absorption features, and we do not sketch the full distribution of chemical composition between grains nor the homogeneity of grains along the observed line of sight. Background image of Cha I. 

 

© NASA, ESA, CSA, and M. Zamani (ESA/Webb); Science: M. K. McClure (Leiden University), F. Sun (Steward Observatory), Z. Smith (Open University), and the Ice Age ERS Team.

---

Using the JWST, a team of researchers including Paola Caselli, Barbara Michela Giuliano and Basile Husquinet from MPE, have probed deep into dense cloud cores, revealing details of interstellar ice that were previously unobservable. The study focuses on the Chamaeleon I region, using JWST’s NIRCam to measure spectroscopic lines toward hundreds of stars behind the cloud. For the first time, weak spectroscopic features known as ‘dangling OH’ have been detected, indicating water molecules are not fully bound in the ice. These features could trace the porosity and modification of icy grains as they evolve from molecular clouds to protoplanetary disks. This discovery enhances our understanding of ice grain structure and its role in planet formation.

Thanks to the unprecedented sensitivity of the JWST, we are able to probe ices deep within dense cloud cores, where extinction is so high that they eluded previous observatories. These lines of sight are the missing link between the initial formation of ices on dust grain surfaces in molecular clouds and the aggregation of icy grains into icy planetesimals, a still little-understood process that occurs in the protoplanetary disk surrounding a new star. Peeking deep into the birthplace of stars will give new clues to these modifications of icy grains.

In the Ice Age program targeting the Chamaeleon I region, a dense cloud region close to us in the Milky Way, observations of the densest part of the cloud with JWST’s NIRCam instrument have allowed simultaneous spectroscopic measurements of lines of sight towards hundreds of stars behind the cloud. The light emitted by these stars interacts with icy grains as it cross the cloud before being captured by the JWST’s large mirror and detected. Up until now, we have been able to measure the major, intense absorption features linked with major species in the ice, namely water, carbon dioxide, carbon monoxide, methanol, and ammonia. Thanks to the large size of the telescope’s mirror, we can now measure much weaker features. In-depth studies of the positions and profiles of weak spectroscopic features reveal some of the physical conditions of the object. Here, we have made the first detection of a particular set of very weak bands linked to only a small fraction of the water molecules in the ice. The spectroscopic features, named ‘dangling OH’ by laboratory astrophysicists who have measured them in laboratory ices for decades, correspond to water molecules that are not fully bound into the ice, and could trace surfaces and interfaces within the icy grains, or when the water is intimately mixed with other molecular species in the ice.

The ‘dangling OH’ features lie in a spectral region that is inaccessible from the ground and so, while they have been actively searched for since the 1990s, the previous space observatories covering that spectral range lacked the combination of spectral resolution and sensitivity required to detect them providing only upper limits. Now in the JWST era, we can use these signatures to trace icy grain modification on the journey to planet formation. It has long been anticipated that, if detected, these signatures could be used to trace the porosity of the ices, i.e. their presence would signal ‘fluffy’ grains with high porosity while their absence would signal compaction and aggregation. Although this simple interpretation remains under debate, the successful detection of these signatures now means that we can search for them in different environments and at different times during the star formation process to determine whether or not they can be used as a tracer of how the ice evolves under different conditions.

"The detection of the water dangling bond feature in the ice mantles demonstrates the importance of laboratory astrophysics to interpret JWST data”, says Barbara Michela Giuliano, one of the authors. “Detailed information on the physical properties of the observed ices still requires extensive support from the laboratory to disentangle the spectral properties observed within dense regions of the interstellar medium and protoplanetary disks. Here at CAS we are happy to provide such support.”, she adds.

“The high sensitivity of JWST, together with impressive advancements in laboratory astrophysics, is finally allowing us to study in detail the physical structure and chemical composition of interstellar ices. This is crucial to provide stringent constraints on chemical/dynamical modeling, needed to reconstruct our astrochemical history, from interstellar clouds to protoplanetary disks to stellar systems like our own. It is exciting to be part of this endeavor.”, says Paola Caselli, who - together with her PhD student Basile Husquinet - also contributed to the paper.

This study shows that, in the cloud, potentially ‘fluffy’ icy grains are present, impacting the chemistry that can occur in these regions and thus the degree of chemical complexity that can build up. The discovery also opens a new window on studying planet formation since, ultimately, these spectral features allow us to build up an idea of the spatial distribution and variation of ices as well as how they evolve on their journey from molecular clouds to protoplanetary disks to planets.

Source: Max Planck Institute for Extraterrestrial Physics (MPE)/News

---

Contact:

Prof. Dr. Paola Caselli
Director of the CAS group at MPE
tel:+49 89 30000-3400
Fax:+49 89 30000-3399
caselli@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics, Garching

Dr. Barbara Michela Giuliano
scientist in CAS group
tel:+49 89 30000-3317
giuliano@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics

Basile Husquinet
PhD-student CAS group
tel:+49 89 30000-3553
bhusquin@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics

---

Original Publication

Noble et al.
Detection of the elusive dangling OH ice features at ∼ 2.7 μm in Chamaeleon I with JWST NIRCam.
Nature Astronomy 2024

Source

---

Further Information

Webb Finds Plethora of Carbon Molecules Around Young Star

An international team of astronomers have used the NASA/ESA/Webb James Webb Space Telescope to study the disc around a young and very low-mass star. The results reveal the richest hydrocarbon chemistry seen to date in a protoplanetary disc (including the first extrasolar detection of ethane) and contribute to our evolving understanding of the diversity of planetary systems. (June 07, 2024)

---