Stellar embryos in nearby dwarf galaxy contain surprisingly complex organic molecules

January 30, 2018, National Radio Astronomy Observatory
Astronomers using ALMA have uncovered chemical 'fingerprints' of methanol, dimethyl ether, and methyl formate in the Large Magellanic Cloud. The latter two molecules are the largest organic molecules ever conclusively detected outside the Milky Way. The far-infrared image on the left shows the full galaxy. The zoom-in image shows the star-forming region observed by ALMA. It is a combination of mid-infrared data from Spitzer and visible (H-alpha) data from the Blanco 4-meter telescope. Credit: NRAO/AUI/NSF; ALMA (ESO/NAOJ/NRAO); Herschel/ESA; NASA/JPL-Caltech; NOAO

The nearby dwarf galaxy known as the Large Magellanic Cloud (LMC) is a chemically primitive place.

Unlike the Milky Way, this semi-spiral collection of a few tens-of-billions of lacks our galaxy's rich abundance of , like carbon, oxygen, and nitrogen. With such a dearth of heavy elements, astronomers predict that the LMC should contain a comparatively paltry amount of complex carbon-based molecules. Previous observations of the LMC seem to support that view.

New observations with the Atacama Large Millimeter/submillimeter Array (ALMA), however, have uncovered the surprisingly clear chemical "fingerprints" of the methanol, dimethyl ether, and methyl formate. Though previous observations found hints of methanol in the LMC, the latter two are unprecedented findings and stand as the most ever conclusively detected outside of our galaxy.

Astronomers discovered the molecules' faint millimeter-wavelength "glow" emanating from two dense star-forming embryos in the LMC, regions known as "hot cores." These observations may provide insights into the formation of similarly complex organic molecules early in the history of the universe.

"Even though the Large Magellanic Cloud is one of our nearest galactic companions, we expect it should share some uncanny chemical similarity with distant, young galaxies from the early universe," said Marta Sewi?o, an with NASA's Goddard Space Flight Center in Greenbelt, Maryland, and lead author on a paper appearing in the Astrophysical Journal Letters.

Astronomers refer to this lack of heavy elements as "low metallicity." It takes several generations of star birth and star death to liberally seed a galaxy with heavy elements, which then get taken up in the next generation of stars and become the building blocks of new planets.

"Young, primordial galaxies simply didn't have enough time to become so chemically enriched," said Sewi?o. "Dwarf galaxies like the LMC probably retained this same youthful makeup because of their relatively low masses, which severely throttles back the pace of star formation."

"Due to its low metallicity, the LMC offers a window into these early, adolescent ," noted Remy Indebetouw, an astronomer at the National Radio Astronomy Observatory in Charlottesville, Virginia, and coauthor on the study. "Star-formation studies of this galaxy provide a stepping stone to understand star formation in the early universe."

The astronomers focused their study on the N113 Star Formation Region in the LMC, which is one of the galaxy's most massive and gas-rich regions. Earlier observations of this area with NASA's Spitzer Space Telescope and ESA's Herschel Space Observatory revealed a startling concentration of young stellar objects - protostars that have just begun to heat their stellar nurseries, causing them to glow brightly in infrared light. At least a portion of this is due to a domino-like effect, where the formation of massive stars triggers the formation of other stars in the same general vicinity.

Sewi?o and her colleagues used ALMA to study several young stellar objects in this region to better understand their chemistry and dynamics. The ALMA data surprisingly revealed the telltale spectral signatures of dimethyl ether and methyl formate, molecules that have never been detected so far from Earth.

Complex organic molecules, those with six or more atoms including carbon, are some of the basic building blocks of molecules that are essential to life on Earth and - presumably - elsewhere in the universe. Though methanol is a relatively simple compound compared to other organic molecules, it nonetheless is essential to the formation of more complex organic molecules, like those that ALMA recently observed, among others.

If these complex molecules can readily form around protostars, it's likely that they would endure and become part of the protoplanetary disks of young star systems. Such molecules were likely delivered to the primitive Earth by comets and meteorites, helping to jumpstart the development of life on our planet.

The astronomers speculate that since complex organic can form in chemically primitive environments like the LMC, it's possible that the chemical framework for life could have emerged relatively early in the history of the universe.

Explore further: Forest of molecular signals observed in star-forming galaxy

More information: "'The detection of hot cores and complex organic molecules in the Large Magellanic Cloud," Astrophysical Journal Letters, 2018.

Related Stories

Forest of molecular signals observed in star-forming galaxy

November 6, 2017

Ryo Ando, a graduate student of the University of Tokyo, and his colleagues have observed the galaxy NGC 253 and resolved its locations of star formation down to the scale of a molecular cloud, a star formation site with ...

Discovery of an extragalactic hot molecular core

September 29, 2016

Astronomers have discovered a 'hot molecular core', a cocoon of molecules surrounding a newborn massive star, for the first time outside our Galaxy. The discovery, which marks the first important step for observational studies ...

Image: Hubble's compact galaxy with big-time star formation

October 16, 2017

As far as galaxies are concerned, size can be deceptive. Some of the largest galaxies in the Universe are dormant, while some dwarf galaxies, such as ESO 553-46 imaged here by the NASA/ESA Hubble Space Telescope, can produce ...

Recommended for you

Study details the history of Saturn's small inner moons

May 22, 2018

The small inner moons of Saturn look like giant ravioli and spaetzle. Their spectacular shape has been revealed by the Cassini spacecraft. For the first time, researchers of the University of Bern show how these moons were ...

Two bright high-redshift quasars discovered

May 21, 2018

Astronomers have detected two new bright quasars at a redshift of about 5.0. The newly found quasi-stellar objects (QSOs) are among the brightest high-redshift quasars known to date. The finding was presented May 9 in a paper ...

First interstellar immigrant discovered in the solar system

May 21, 2018

A new study has discovered the first known permanent immigrant to our Solar System. The asteroid, currently nestling in Jupiter's orbit, is the first known asteroid to have been captured from another star system. The work ...


Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (3) Jan 31, 2018
The plasma ignoramuses will always be surprised by observation when applied to their fanciful faerie tales of stellar evolution due to the fact their religion has no basis in reality. Only fanciful pontifications of matter we know by experiments does not exist anywhere other than their maths equations and GIGO simulations.
5 / 5 (4) Feb 01, 2018
The people who think they know science but never worked in the field and never pursued knowledge at a high college level will always talk trash about professionals in the area, dismissing evidence and observations due to the fact that they think FUD is the best way to "come out on top" and to twist reality to better fit their igorant world views. It's easier to be a pseudo-science internet troll than to actually do the specific science work. If not, these people would be working WITH the astronomers and astrophysicists in finding out the truth about the Universe, not AGAINST them.
1 / 5 (4) Feb 01, 2018
dismissing evidence and observations

This is why it is so easy to be dismissive of the plasma ignoramuses. Since most "theories" regarding the space sciences were postulated prior to the space age and in situ measurements of space plasmas and the fact nothing has really changed in the foundational principles of said sciences regardless of how dramatically wrong the plasma behaves as compared to their fanciful pseudoscientific faerie tales of "ionized gases" then it is the astrophysicists and astronomers who are working against themselves in finding the truth about the Universe. Besides, as history shows repeatedly, paradigm shifting advancements in the sciences comes from without and not within the established scientific community. The plasma ignoramuses are far too immersed in their religious beliefs of Einsteinism and the Dark Side to see what would otherwise be obvious.
5 / 5 (4) Feb 01, 2018
This is why science continues making discoveries while the willfully ignorant invent their own pseudo-"science" and just troll away anonymously on websites, lying and lying and defaming the people who actually spend literally decades working. They comment a whole lot, but say nothing meaningful and true. It's way harder to get a degree in the scientific field, to get an education on the matter and do the real pursuit of knowledge/truth, using the tools modern technology has provided, like space probes, telescopes and other scientific instruments. To analyze data, to write and publish scientific articles, to peer-review them.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.