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Filaments Created by Sonic Booms?

Posted: April 19th, 2011, 7:20 pm
by Christopher K.
The Herschel Space Observatory has discovered that filaments of material in nearby interstellar clouds, regardless of length or density, seem to have the same width. This suggest they may have been formed by the equivalent of sonic booms in space. The team, led by Doris Arzoumanian of Laboratoire AIM Paris-Saclay, looked at ninety filaments and found them all to be about 0.3 light years across.

One cloud investigated was IC 5146, the fifteen light year-wide Cocoon Nebula, 4000 light years away in Cygnus. The cluster associated with the nebula are mainly 12th-magnitude stars.

A single filament found in the constellation Aquila contains at least 100 newborn stars. Aquila occupies a little over 650 square degrees of sky between Hercules and Aquarius, and its brightest star (magnitude 0.8 Altair) forms the "Summer Triangle" with Deneb and Vega.

It should be noted that due to the temperature of the clouds (around 10 Kelvin) the speed of sound is slower than at sea level on Earth.

More information at: ... 10413.html

Nice Cocoon Nebula image:

Re: Filaments Created by Sonic Booms?

Posted: June 6th, 2020, 6:21 pm
by Christopher K.
Jeffrey O. Johnson got a nice image of the Cocoon Nebula from his backyard in Las Cruces, New Mexico using a Takahashi FS-C60 refractor. He contributed it to the June 2020 Reflector.

Here is another image of the Cocoon from Herschel... ... 14038.html