Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Comets Forge Organic Molecules in Their Dusty Atmospheres, ALMA Confirms

13.08.2014

An international team of scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) has made incredible 3D images of the ghostly atmospheres surrounding comets ISON and Lemmon. These new observations provided important insights into how and where comets forge new chemicals, including intriguing organic compounds.

Comets contain some of the oldest and most pristine materials in our Solar System. Understanding their unique chemistry could reveal much about the birth of our planet and the origin of organic compounds that are the building blocks of life. ALMA's high-resolution observations provided a tantalizing 3D perspective of the distribution of the molecules within these two cometary atmospheres, or comas.


Credit: B. Saxton (NRAO/AUI/NSF); NASA/ESA Hubble; M. Cordiner, NASA, et al.

Approximate location of Comet ISON in our Solar System at the time of the ALMA observations.


Visualization by Brian Kent (NRAO/AUI/NSF)

This rotating 3-D ALMA map shows how HCN molecules (made of one hydrogen, one carbon and one nitrogen) are released from the nucleus of comet Lemmon and then spread evenly throughout the atmosphere, or coma. But, similar maps revealed that HNC and formaldehyde are produced in the coma, rather than originating from the comet's nucleus.

“We achieved truly first-of-a-kind mapping of important molecules that help us understand the nature of comets,” said team leader Martin Cordiner, a Catholic University of America astrochemist working at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

The critical 3D component of the ALMA observations was made by combining high-resolution, two-dimensional images of the comets with high-resolution spectra obtained from three important organic molecules – hydrogen cyanide (HCN), hydrogen isocyanide (HNC), and formaldehyde (H2CO). These spectra were taken at every point in each image. They identified not only the molecules present but also their velocities, which provided the third dimension, indicating the depths of the cometary atmospheres.

The new results revealed that HCN gas flows outward from the nucleus quite evenly in all directions, whereas HNC is concentrated in clumps and jets. ALMA’s exquisite resolution could clearly resolve these clumps moving into different regions of the cometary comas on a day-to-day and even hour-to-hour basis. These distinctive patterns confirm that the HNC and H2CO molecules actually form within the coma and provide new evidence that HNC may be produced by the breakdown of large molecules or organic dust.

"Understanding organic dust is important, because such materials are more resistant to destruction during atmospheric entry, and some could have been delivered intact to the early Earth, thereby fueling the emergence of life,” said Michael Mumma, director of the Goddard Center for Astrobiology and a co-author on the study. "These observations open a new window on this poorly known component of cometary organics."

“So, not only does ALMA let us identify individual molecules in the coma, it also gives us the ability to map their locations with great sensitivity,” said Anthony Remijan, an astronomer with the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, and a study co-author.

The observations, published today in the Astrophysical Journal Letters, were also significant because modest comets like Lemmon and ISON contain relatively low concentrations of these crucial molecules, making them difficult to probe in depth with Earth-based telescopes. The few comprehensive studies of this kind so far have been conducted on extremely bright comets, such as Hale-Bopp. The present results extend them to comets of only moderate brightness.

Comet ISON (formally known as C/2012 S1) was observed with ALMA on November 15-17, 2013, when it was only 75 million kilometers from the Sun (about half the distance of the Earth to the Sun). Comet Lemmon (formally known as C/2012 F6) was observed on June 1-2, 2013, when it was 224 million kilometers from the Sun (about 1.5 times the distance of the Earth to the Sun).

"The high sensitivity achieved in these studies paves the way for observations of perhaps hundreds of the dimmer or more distant comets,” said Goddard’s Stefanie Milam, a study co-author. “The findings suggest that it should also be possible to map more complex molecules that have so far eluded detection in comets.”

This research was funded by the NASA Astrobiology Institute through the Goddard Center for Astrobiology and by NASA’s Planetary Atmospheres and Planetary Astronomy programs.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Southern Observatory (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

Contact Information

Charles Blue
cblue@nrao.edu
Phone: 434-296-0314
Mobile: 202-236-6324

Charles Blue | newswise
Further information:
http://www.nrao.edu

Further reports about: Astrobiology Astronomy Atmospheres Molecules Observatory Organic Planetary clumps comets observations

More articles from Physics and Astronomy:

nachricht Distant planet's interior chemistry may differ from our own
01.09.2015 | Carnegie Institution

nachricht Interstellar seeds could create oases of life
28.08.2015 | Harvard-Smithsonian Center for Astrophysics

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: An engineered surface unsticks sticky water droplets

The leaves of the lotus flower, and other natural surfaces that repel water and dirt, have been the model for many types of engineered liquid-repelling surfaces. As slippery as these surfaces are, however, tiny water droplets still stick to them. Now, Penn State researchers have developed nano/micro-textured, highly slippery surfaces able to outperform these naturally inspired coatings, particularly when the water is a vapor or tiny droplets.

Enhancing the mobility of liquid droplets on rough surfaces could improve condensation heat transfer for power-plant heat exchangers, create more efficient...

Im Focus: Increasingly severe disturbances weaken world's temperate forests

Longer, more severe, and hotter droughts and a myriad of other threats, including diseases and more extensive and severe wildfires, are threatening to transform some of the world's temperate forests, a new study published in Science has found. Without informed management, some forests could convert to shrublands or grasslands within the coming decades.

"While we have been trying to manage for resilience of 20th century conditions, we realize now that we must prepare for transformations and attempt to ease...

Im Focus: OU astrophysicist and collaborators find supermassive black holes in quasar nearest Earth

A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.

The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...

Im Focus: What would a tsunami in the Mediterranean look like?

A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).

Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African...

Im Focus: Self-healing landscape: landslides after earthquake

In mountainous regions earthquakes often cause strong landslides, which can be exacerbated by heavy rain. However, after an initial increase, the frequency of these mass wasting events, often enormous and dangerous, declines, in fact independently of meteorological events and aftershocks.

These new findings are presented by a German-Franco-Japanese team of geoscientists in the current issue of the journal Geology, under the lead of the GFZ...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking conference in Heidelberg for outstanding mathematicians and computer scientists

20.08.2015 | Event News

Scientists meet in Münster for the world’s largest Chitin und Chitosan Conference

20.08.2015 | Event News

Large agribusiness management strategies

19.08.2015 | Event News

 
Latest News

Siemens sells 18 industrial gas turbines to Thailand

01.09.2015 | Press release

An engineered surface unsticks sticky water droplets

01.09.2015 | Materials Sciences

New material science research may advance tech tools

01.09.2015 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>