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Flying telescope yields insights into birth of stars

From BBC - January 9, 2018

A Nasa telescope housed on a converted jumbo jet has yielded important insights into how stars are born from collapsing gas and dust.

Measurements by the Sofia observatory underline the importance of magnetic fields for star formation.

Astronomers used an instrument on Sofia to study one of the closest stellar nurseries to Earth - Rho Ophiuchi A.

They discussed details of the work at the 231st American Astronomical Society meeting.

"Understanding how stars and planets are formed is one of the greatest challenges of modern astronomy," said co-author Fabio Santos, from Northwestern University in Evanston, Illinois.

"We know that stars and planets are formed in giant clouds of molecular gas and dust that exist in the plane of the Milky Way galaxy."

The basic idea is that these clouds contract under their own gravity. Becoming ever more dense, they fragment into gaseous clumps and, from there, dense structures called "cores" are formed.

It is within these dense cores of dust and gas that infant stars are found.

But the devil is in the detail: "It's a very complicated process," said Dr Santos.

The astronomers trained Sofia's HAWC+ instrument on Rho Ophiuchi A, which is actively forming hundreds of young stars. Many of which will probably become stars like our Sun, complete with their own planetary systems.

HAWC+ is sensitive to emission in the far-infrared portion of the electromagnetic spectrum. Data from the instrument allowed researchers to show that dust grains in the cloud were aligned with magnetic fields.

Furthermore, they found that changes in the way dust aligned along field lines were closely related to differences in the density of the star-forming cloud. The measurement represents the first of its kind - and Sofia is uniquely equipped to perform such observations.

The result supports an existing theory called Radiative Alignment Torque (RAT).

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