First time, complex organic compound outside Milkyway galaxy found

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. NASA/JPL-Caltech

Atacama Large Millimeter/submillimeter Array (ALMA) has identified chemical fingerprints of the complex organic molecules methanol, dimethyl ether, and methyl formate in our nearby dwarf galaxy known as Large Magellanic Cloud (LMC) for the first time outside the Milkyway galaxy.

The semi-spiral galaxy with nearly tens-of-billions of stars were in a state known as "low metallicity", which lacked heavy elements like carbon, oxygen, and nitrogen.

Marta Sewilo, an astronomer with NASA's Goddard Space Flight Center in Greenbelt, Maryland and lead author of the paper said, "Even though the Large Magellanic Cloud is one of our nearest galactic companies, we expect it should share some uncanny chemical similarity with distant, young galaxies from the early universe."

Astronomers identified faint millimeter-wavelength "glow" from two dense star-forming embryos in regions of the LMC known as "hot cores". This observation has led to the finding of similarly complex organic molecules from the early history of the Universe.

According to the paper published in the Astrophysical Journal Letters, several events of star births and star deaths lead to the formation of a galaxy with heavy elements. New planets are formed here by more evolved stars.

Younger primitive galaxies do not usually have enough time to become chemically complex. But dwarf galaxies like LMC could have probably retained their youthful makeup due to their relatively lower masses.

Astronomers say that LMC can be helpful in studying early, adolescent galaxies due to its lower metallicity. This can give a better understanding of star formation in the early universe.

The study was focused on the N113 Star Formation Region in the LMC which is one of the most massive and gas-rich regions of the galaxy. NASA's Spitzer Space Telescope and ESA's Herschel Space Observatory has earlier found that the region contained a large number of young stellar objects known as protostars. These objects had just started to heat their nearby stellar nurseries of gas and dust resulting in its bright infrared light glow.

A domino-like effect which triggers the formation of stars near massive stars in the galaxy is also found in certain regions of the galaxy.

The study using ALMA has also resulted in the discovery of spectral signatures of dimethyl ether and methyl formate which were never been detected on Earth. Complex organic molecules are the basic building blocks of life on Earth. Simple organic compounds like methanol are also essential to the formation of larger organic compounds.

The discovery of these life forming organic compounds around protostars gives hope that they might have formed during the relatively early history of the Universe.