PSU: Stellar Winds, Source Material for the Universe, Are Clumpy

Find out the latest thinking about our universe.
Post Reply
User avatar
bystander
Apathetic Retiree
Posts: 21571
Joined: Mon Aug 28, 2006 2:06 pm
Location: Oklahoma

PSU: Stellar Winds, Source Material for the Universe, Are Clumpy

Post by bystander » Thu Jan 24, 2019 9:37 pm

Stellar Winds, the Source Material for the Universe, Are Clumpy
Eberly College | Penn State University | 2019 Jan 24
psrb1259_cartoon.jpg
Illustration of a high-mass X-ray binary system made up of a compact, incredibly dense
neutron star paired with a massive normal supergiant star. New data from NASA's
Chandra X-ray Observatory shows that the neutron star in the high-mass X-ray binary,
OAO 1657-415, passed through a dense patch of stellar wind from its companion star,
demonstrating the clumpy nature of stellar winds. (Credit: NASA/CXC/M.Weiss)

Data recorded by NASA’s Chandra X-ray Observatory of a neutron star as it passed through a dense patch of stellar wind emanating from its massive companion star provide valuable insight about the structure and composition of stellar winds and about the environment of the neutron star itself. ...

The neutron star observed is part of a high-mass X-ray binary system—the compact, incredibly dense neutron star paired with a massive ‘normal’ supergiant star. Neutron stars in binary systems produce X-rays when material from the companion star falls toward the neutron star and is accelerated to high velocities. As a result of this acceleration, X-rays are produced that can inturn interact with the materials of the stellar wind to produce secondary X-rays of signature energies at various distances from the neutron star. Neutral—uncharged—iron atoms, for example, produce fluorescence X-rays with energies of 6.4 kilo-electron volts (keV), roughly 3000 times the energy of visible light. Astronomers use spectrometers, like the instrument on Chandra, to capture these X-rays and separate them based on their energy to learn about the compositions of stars. ...

The researchers also used the Chandra’s state-of-the-art engineering to identify a lower limit on the distance from the neutron star that the X-rays from neutral iron are formed. Their spectral analysis showed that neutral iron is ionized at least 2.5 light-seconds, a distance of approximately 750 million meters or nearly 500,000 miles, from the neutron star to produce X-rays. ...

Multitude of Iron Lines Including a Compton-Scattered Component
in OAO 1657-415 Detected with Chandra
~ Pragati Pradhan et al
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

Post Reply