Starship Asterisk*

Stardust in Aries

Explanation: This composition in stardust covers almost 2 degrees on the sky, close to the border of the zodiacal constellation Aries and the plane of our Milky Way Galaxy. At the lower right of the gorgeous skyscape is a dusty blue reflection nebula surrounding a bright star cataloged as van den Bergh 13 (vdB 13), about 1,000 light-years away. At that estimated distance, the cosmic canvas is over 30 light-years across. Also surrounded by scattered blue starlight, vdB 16 lies toward the upper left, while dark dusty nebulae sprawl across the scene. Near the edge of a large molecular cloud, they can hide the newly formed stars and young stellar objects or protostars from prying optical telescopes. Collapsing due to self-gravity, the protostars form around dense cores embedded in the molecular cloud.

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Stellar dust is very photogenic and in this case the picture is great.
Greetings
César

How dense is the stardust? Is it like fog or thick enough for gravity to be a factor in star formation?

Faziof@bellsouth.net wrote:
How dense is the stardust? Is it like fog or thick enough for gravity to be a factor in star formation?

Think of it in terms of a hazy day where the visibility is defined in light-years (i.e., 10 trillion kilometer units) rather than just kilometers.

Great background picture!

The stars in this photo appear to be different sizes. Do we actually see the disks of the stars? Or do telescopes see all stars as points of light, with the different sizes caused by lens flare or some other phenomenon.

I have always wondered. If we can actually see the disks of the stars, is it possible to see "starspots" (like sunspots), prominences and other stellar features?

K1NS wrote:The stars in this photo appear to be different sizes. Do we actually see the disks of the stars? Or do telescopes see all stars as points of light, with the different sizes caused by lens flare or some other phenomenon.

Optically, nearly all stars are point sources to telescopes such as we have built. The finite aperture of the scope produces diffraction, which broadens the stellar image at the focal plane. The broadening is the same for all stars, but the brighter stars let us see further out on the broadened profile, so bright stars appear to have larger diameters.

I have always wondered. If we can actually see the disks of the stars, is it possible to see "starspots" (like sunspots), prominences and other stellar features?

A handful of the closest, largest stars can have their discs resolved optically, and on those it is possible to see some features such as large hot or cool areas. Otherwise, some features can be studied on stars too small or distant to resolve, by using photometric analysis- as a star turns, features come in and out of view, changing the stellar brightness. Observe this long enough, and you can build up details about the stellar surface.