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“Space hamburger” spotted in astronomical first

A newborn star buried deep inside the Orion Nebula is feeding on a giant, dusty “space hamburger,” researchers have discovered.

This astronomical sandwich is actually an accretion disk, or a cloud of gas and dust that rotates around a central point — in this case, a young protostar. Astronomers have seen these disks around stars and even black holes before, but this is the first time anyone has seen one that looks like a giant hamburger.

Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, researchers found more than just the first “space hamburger” — their observations also confirmed that accretion disks can form in the earliest phase of star formation. Because disks around young stars are relatively tiny, astronomers have not been able to clearly image them in the past, the study’s authors explain in the new research paper. [Amazing Photos from the Giant ALMA Radio Telescope

Thanks to the higher sensitivity and resolution of ALMA’s telescopes, researchers were able to detect a protostellar disk around a baby star for the first time while getting a detailed look at its structure.

Though the researchers suspected they’d find a protostellar disk, the hamburger-like shape came as a surprise, Chin-Fei Lee, a researcher at the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan, who led the study, told Space.com in an email.

Instead of a round, homogeneous blob, Lee’s team saw a dark zone (the analogical beef patty) sandwiched between two brighter features. To see this so-called “equatorial lane,” the protostellar disk must be observed close to edge-on, Lee said. Its midplane must also be colder than the “hamburger” buns and opaque in the observed wavelength.

“It is so amazing to see such a detailed structure of a very young accretion disk,” Lee said in a statement. “For many years, astronomers have been searching for accretion disks in the earliest phase of star formation, in order to determine their structure, how they are formed and how the accretion process takes place. Now, using the ALMA with its full power of resolution, we not only detect an accretion disk but also resolve it, especially its vertical structure, in great detail.”

Images of the HH 212 protostellar system: (a) Molecular jets of gassy material spewing out of the young star’s poles are seen in this composite image created with a combination of data from different telescopes. (b) A close-up of the center of the protostellar disk reveals the hamburger-shaped dust cloud around the central star. A dark layer is seen around the equator. A scale model of Earth’s solar system is included for size comparison. (c) Using a new computer model, the researchers were able to reproduce the observed dust emission in the disk.

Lee et al./ALMA/ESO/NAOJ/NRAO

But not all protostellar disks look like hamburgers, Lee said….

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