WebProNews

Tag: ALMA

  • Three Ancient Galaxies Spotted Merging

    Astronomers this week revealed that they have spotted three ancient galaxies that appear to be merging. The observations, which were made using both the Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA) are recorded in a paper to be published in The Astrophysical Journal.

    The three galaxies are located inside a large gas cloud that is located almost 13 billion light-years from our solar system. This means the galaxies are seen as they were less than one billion years after the big bang. Astronomers believe that the galaxies might have eventually merged, forming a larger galaxy similar to the ones we are more familiar with today.

    “This exceedingly rare triple system, seen when the Universe was only 800 million years old, provides important insights into the earliest stages of galaxy formation during a period known as ‘Cosmic Dawn,’ when the Universe was first bathed in starlight,” said Richard Ellis, a member of the research team and an astronomer at the California Institute of Technology. “Even more interesting, these galaxies appear poised to merge into a single massive galaxy, which could eventually evolve into something akin to the Milky Way.”

    The gas cloud, which researchers have dubbed “Himiko” was first spotted in 2009 and was seen as a single gas cloud. However, the size of the cloud is, according to the National Radio Astronomy Observatory, almost ten times larger than the nebulous galaxies that are found that early in the universe. This led to the new observations, which revealed that three distinct sources of light within the larger cloud.

    What astronomers did not find, however, could end up being their most interesting observation. The team did not detect any carbon in Himiko, which is one of the first elements created by young stars.

    “When this dust is heated by ultraviolet radiation from massive newborn stars, the dust then re-radiates at radio wavelengths,” said Kotaro Kohno, a member of the research team and an astronomer at the University of Tokyo. “Such radiation is not detected in Himiko.”

    Kohno and his colleagues currently believe that this could signal that Himiko is, in fact, a primordial galaxy made up mostly of hydrogen and helium gas. This would make it one of the first primordial galaxies to be caught during its early formation.

    (Image courtesy NASA/Hubble; NAOJ/Subaru)

  • ‘Snow Line’ Spotted in Young Solar System

    Astronomers this week revealed that the first-ever “snow line” of a solar system has been spotted. Scientists believe that the snow line – similar to ones seen on the tops of mountains on Earth – could provide information about how planets with differing chemical compositions evolve around young stars.

    In the far reaches of accretion discs around young stars, molecules such as water, carbon dioxide, and methane freeze around dust grains that will eventually coalesce into planets. The line where such behavior begins was spotted around the star TW Hydrae, a star located 175 light-years away that astronomers believe is similar to what our solar system once was. An image of the snow line was taken using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, and the results of the research have been published in the journal Science Express.

    “ALMA has given us the first real picture of a snow line around a young star, which is extremely exciting because of what it tells us about the very early period in the history of our own Solar System,” said Chunhua Qi, a leader of the research team and an astrophysicist at the Harvard-Smithsonian Center for Astrophysics. “We can now see previously hidden details about the frozen outer reaches of another solar system, one that has much in common with our own when it was less than 10 million years old.”

    This is the first direct image of a snow line ever captured. As insulating clouds of warm gas cloak snow lines, the regions are normally detected using spectral signatures. Qi and his colleagues were able to use ALMA to look for a specific molecule called diazenylium, which should only appear in regions where carbon monoxide (CO) is frozen. TW Hydrae’s snow line was found at around 30 astronomical units (AU, the distance from the Earth to the Sun) from the star.

    “Using this technique, we were able to create, in effect, a photonegative of the CO snow in the disk surrounding TW Hydrae,” said Karin Oberg, another leader in the research and an astrochemist at Harvard University. “With this we could see the CO snow line precisely where theory predicts it should be — the inner rim of the diazenylium ring.”

    (Image courtesy Bill Saxton/Alexandra Angelich, NRAO/AUI/NSF

  • Astronomers Spot Massive Star In-Utero

    Astronomers using the European Southern Observatory‘s Atacama Large Millimeter/submillimeter Array (ALMA) this week revealed that they have spotted a massive star in the process of being born. Researchers hope the new information can help uncover just how massive (stars with more than 10 times the mass of the sun) stars form.

    “The remarkable observations from ALMA allowed us to get the first really in-depth look at what was going on within this cloud,” said Nicolas Peretto, an astronomer at Cardiff University. “We wanted to see how monster stars form and grow, and we certainly achieved our aim. One of the sources we have found is an absolute giant – the largest protostellar core ever spotted in the Milky Way.”

    The most massive protostar was seen in a cloud called the Spitzer Dark Cloud 335.579-0.292, located 11,000 light-years from our solar system. It was spotted using the array’s microwave scan capabilities. The core of the protostar is over 500 times more massive than the sun, with material from surrounding clouds still increasing its size. Astronomers believe it will, in the future, collapse into a star that could be 100 times more massive than the sun.

    “Even though we already believed that the region was a good candidate for being a massive star-forming cloud, we were not expecting to find such a massive embryonic star at its centre,” said Peretto. “This object is expected to form a star that is up to 100 times more massive than the Sun. Only about one in ten thousand of all the stars in the Milky Way reach that kind of mass!”

    (Image courtesy ESO)