APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 08)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 3669
Joined: Fri Dec 04, 2009 3:27 am

APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 08)

Post by APOD Robot » Wed Oct 08, 2014 4:06 am

Image NGC 6823: Cloud Sculpting Star Cluster

Explanation: Star cluster NGC 6823 is slowly turning gas clouds into stars. The center of the open cluster, visible on the upper right, formed only about two million years ago and is dominated in brightness by a host of bright young blue stars. Some outer parts of the cluster, visible in the featured image's center as the stars and pillars of emission nebula NGC 6820, contain even younger stars. The huge pillars of gas and dust likely get their elongated shape by erosion from hot radiation emitted from the brightest cluster stars. Striking dark globules of gas and dust are also visible across the upper left of the featured image. Open star cluster NGC 6823 spans about 50 light years and lies about 6000 light years away toward the constellation of the Fox (Vulpecula).

<< Previous APOD This Day in APOD Next APOD >>
[/b]

starsurfer
Stellar Cartographer
Posts: 3690
Joined: Thu Mar 15, 2012 7:25 pm

Re: APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 0

Post by starsurfer » Wed Oct 08, 2014 6:27 am

I much prefer this in true colour.

User avatar
Ann
4725 Å
Posts: 9748
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 0

Post by Ann » Wed Oct 08, 2014 6:28 am

Me too.

Ann
Color Commentator

User avatar
Nitpicker
Inverse Square
Posts: 2689
Joined: Fri Sep 20, 2013 2:39 am
Location: S27 E153

Re: APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 0

Post by Nitpicker » Wed Oct 08, 2014 7:22 am

The stars have been overlaid in RGB.

Does the best "true colour" image of the nebula show more detail than this narrowband Hubble palette map?

User avatar
geckzilla
Ocular Digitator
Posts: 8977
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA

Re: APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 0

Post by geckzilla » Wed Oct 08, 2014 7:40 am

Multiple grayscale images of data collected from appropriate narrowband filters would be the most informative and most detailed. Combining them is just so much more fun.
Just call me "geck" because "zilla" is like a last name.

User avatar
Chris Peterson
Abominable Snowman
Posts: 14511
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 0

Post by Chris Peterson » Wed Oct 08, 2014 11:30 am

starsurfer wrote:I much prefer this in true colour.
Aesthetics are subjective, of course.

In "true" color this object is basically nothing but reds. In terms of information content, narrowband images offer a great deal more information. I can't find any high quality RGB images of NGC 6823 that show half the detail of this one.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Boomer12k
:---[===] *
Posts: 2572
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 0

Post by Boomer12k » Wed Oct 08, 2014 6:19 pm

The false color images were giving me the impression this is a Reflection Nebula.....but that does not show in other images...and descriptions say it is an Emission Nebula...

I can only assume they do this to delineate a certain detail they wish to study???? Evidently what Chris said....

:---[===] *

star struck

Re: APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 0

Post by star struck » Wed Oct 08, 2014 9:10 pm

The cornucopia of star dust associated with nebula NGC 6823 looks inviting.
Mars could use some of that dust and gas. And the Earth could sure do with a helping of precious metal and water. And Venus would shine brighter with a shield of helium and neon protecting it from the ultraviolet rays of the Sun. It is novel that the Solar System is itself immersed in a bubble of dust and gas known as the Local Bubble and churning with interstellar particles.
In a few days a comet approximately 3 km in diameter is expected to brush past Mars. But there is also the possibility of a direct impact with the planet. If that should happen Mars would be enriched with water and silicate rock and noble gases sufficiently to make a significant climatic change on the planet.
The largest of the Levy Shoemaker comet which impacted Jupiter was about 2 km in diameter. This would imply a total mass in the order of approximately 9 billion tons. That comet plunged into Jupiter and effectively became lost forever from the universe.
A comet approximately 3 km in diameter impacting Mars would effectively resurface much of the landscape of the planet.
But by the time it has arrived at the impact site the comet will have turned into a slurry snow ball with much of the interior melted by the Sun. It would essentially splash on the surface of Mars or disintegrate in the atmosphere in a sudden windy rainfall. Or the comet could just as well collide with one of the Mars moons. Or alter the moon orbital characteristics.
It would be interesting to see if the comet hastens the orbital decay of the Martian moon Phobos.

User avatar
Chris Peterson
Abominable Snowman
Posts: 14511
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 0

Post by Chris Peterson » Wed Oct 08, 2014 9:15 pm

star struck wrote:That comet plunged into Jupiter and effectively became lost forever from the universe.
Not at all. Essentially all of the matter than makes up our Solar System is "lost to the Universe" for the moment. But only for the moment. It will all be returned for recycling in a few billion years.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
rstevenson
Quis custodiet ipsos custodes?
Posts: 2592
Joined: Fri Mar 28, 2008 1:24 pm
Location: Dartmouth, NS, Canada

Re: APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 0

Post by rstevenson » Thu Oct 09, 2014 12:18 am

Chris Peterson wrote:
star struck wrote:That comet plunged into Jupiter and effectively became lost forever from the universe.
Not at all. Essentially all of the matter than makes up our Solar System is "lost to the Universe" for the moment. But only for the moment. It will all be returned for recycling in a few billion years.
Not sure what you mean there Chris. There'll be a significant chunk of the Sun left, in the form of a white dwarf. And the outer planets, the asteroid belt, the Oort Cloud -- essentially everything solid outside the Earth's orbit -- will be pretty much unaffected by the demise of the Sun in a few billion years.

As for the OP's "lost forever from the universe", I can't attach a realistic event or sequence of events to that thought. An asteroid is no more lost to the universe after it hits a planet than it was before. Perhaps when something passes over the event horizon of a black hole it can be described as lost forever from the universe, but that's about it -- and even then I'd want to qualify the remark by adding "the universe as we know it."

Rob

starsurfer
Stellar Cartographer
Posts: 3690
Joined: Thu Mar 15, 2012 7:25 pm

Re: APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 0

Post by starsurfer » Fri Oct 10, 2014 11:05 am

Chris Peterson wrote:
starsurfer wrote:I much prefer this in true colour.
Aesthetics are subjective, of course.

In "true" color this object is basically nothing but reds. In terms of information content, narrowband images offer a great deal more information. I can't find any high quality RGB images of NGC 6823 that show half the detail of this one.
A HaRGB image would combine the excellent narrowband detail with "true" colour. For example, this HaLRGB image by Bob Franke shows nice detail and the LRGB data helps preserve the many small reflection nebulae in the area: http://bf-astro.com/ngc6820/ngc6820.htm

User avatar
Chris Peterson
Abominable Snowman
Posts: 14511
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: NGC 6823: Cloud Sculpting Star Cluster (2014 Oct 0

Post by Chris Peterson » Fri Oct 10, 2014 2:14 pm

starsurfer wrote:A HaRGB image would combine the excellent narrowband detail with "true" colour. For example, this HaLRGB image by Bob Franke shows nice detail and the LRGB data helps preserve the many small reflection nebulae in the area: http://bf-astro.com/ngc6820/ngc6820.htm
I disagree. Still only a fraction of the structure is visible. With HaRGB we still only get a single channel of narrowband, which largely overlaps the dominant wideband signal (most of the light is coming from Ha). It is the addition of the two other narrow channels, combined with the reduction in continuum that lets us see structure.

In addition, our ability to discriminate subtle color changes is very poor in the reds, so we lose additional detail. Simply presenting the Ha data as blue, for instance, would let us see more even in an HaRGB.

We can argue what makes a subjectively more aesthetic image, but there's little doubt that you don't want to include continuum light if the goal is to maximize the information we can take from it.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com