Starship Asterisk*

by **orin stepanek** » Tue Jan 02, 2007 2:57 pm

Thanks Harry; but I was hoping for a more updated look of the pictures that BMAONE23 posted.

Orin

by **harry** » Mon Jan 01, 2007 11:59 pm

Hello All

Hello Orin

see also previous APOD
V838 Mon: Light Echo Update
http://antwrp.gsfc.nasa.gov/apod/ap050204.html
2005 February 4

After detecting a sudden outburst from the star in 2002, astronomers have followed the flash expanding at the speed of light through pre-existing dust clouds surrounding the reddened variable star

by **orin stepanek** » Fri Dec 29, 2006 2:58 pm

I'd like to see what this looks like today; if the reflections changed anymore. Something has to be happening there.
http://imgsrc.hubblesite.org/hu/db/2006 ... /print.jpg

Orin

by **Pete** » Fri Dec 29, 2006 3:04 am

Sorry about reviving an old topic, but I kind of forgot about it, never answered, and saw it again just now...

By saying the changes in the image are due to light rather than structure, I meant that the swirling motions and brightness differences seen in the two pictures are due to the light echo moving through the interstellar material surrounding V838 Monocerotis. The apparent structural changes (swirling, etc.) are due to light reflecting off different regions of the star's surroundings, not the actual movement of matter.

The above posters are right in pointing out that the light echo reflects the structure of the star's environment and provides 3D information about the material around the star.

by **BMAONE23** » Tue Oct 31, 2006 6:01 pm

I would also think that as the ECHO moves through the structure it would display the 3D depth of the structure thereby painting a good visual of the entire structure.

by **orin stepanek** » Tue Oct 31, 2006 2:30 pm

I'M confused Pete? It is a light echo yes, but; the echo reflects structure. Does it not?

Orin

by **Nereid** » Tue Oct 31, 2006 1:41 pm

For those interested, this Hubblesite page has some basic info about the (original) Hubble image - location (RA and Dec), and distance to M16.

Unfortunately, no scale bar or orientation arrows (these were added to Hubble PR images some time after 1995).

by **Pete** » Mon Oct 30, 2006 2:20 pm

BMAONE23 wrote:Today's new Hubble image shows a dramatic difference with what appears to be new stellar activity at the 9:00 position in this image http://imgsrc.hubblesite.org/hu/db/2006 ... /print.jpg of variable star V838 Monocerotis (V838 Mon). There is a dramatic change in less than a year.

That image is labeled "light echo". From the HubbleSite description ( http://hubblesite.org/newscenter/archiv ... s/2006/50/ ),

These are the most recent NASA Hubble Space Telescope views of an unusual phenomenon in space called a light echo. Light from a star that erupted nearly five years ago continues propagating outward through a cloud of dust surrounding the star. The light reflects or "echoes" off the dust and then travels to Earth.

It's a picture of the ongoing aftermath of the 2003 flare-up described here: http://www.hypography.com/article.cfm?id=32954

The differences seen in the pictures are light, not structure.

by **orin stepanek** » Sun Oct 29, 2006 4:45 am

BMAONE23 wrote:What I think would be really interesting woud be to have the Hubble train its eye on this phenom daily for 3 to 6 months and produce a GIF from daily frames to show a movie of the actions in near real time.

That would be neat! I noticed some dust cleared in the top also.

Orin

by **BMAONE23** » Sat Oct 28, 2006 6:29 pm

What I think would be really interesting woud be to have the Hubble train its eye on this phenom daily for 3 to 6 months and produce a GIF from daily frames to show a movie of the actions in near real time.

by **orin stepanek** » Sat Oct 28, 2006 4:44 pm

Thanks BMAONE23! And at the 3oclock position you can see that the 2 stars at the edge of the photo have cleared away quite a bit of space dust also. Back to the 9oclock position it looks like the dust is curling inward and there looks to be some new twinkling there.

Orin

by **BMAONE23** » Sat Oct 28, 2006 3:56 pm

Today's new Hubble image shows a dramatic difference with what appears to be new stellar activity at the 9:00 position in this image http://imgsrc.hubblesite.org/hu/db/2006 ... /print.jpg of variable star V838 Monocerotis (V838 Mon). There is a dramatic change in less than a year.

by **orin stepanek** » Wed Oct 25, 2006 4:59 pm

Though it takes millions of years of formation for a star to be born there still has to be that moment. I would be happy to catch that moment!:roll: Orin

by **iamlucky13** » Wed Oct 25, 2006 12:04 am

orin stepanek wrote:I'LL be delighted if one gets caught starting to twinkle. I hope somebody can answer if the probability of catching one firing up is forthcoming.
Orin

That'd be pretty sweet, but I don't suppose it's a lightswitch sort of affect.

I'd tend to expect that as the mass increases, the body slowly heats up in the infrared due to friction from the accretion of matter. As it gains enough mass for fusion to begin, it warms up faster, but as I understand this should first occur near the core, so we might still only see this happen in infrared, like a brown dwarf. As the density increases, so does the fusion rate, and the star gradually begins to shine in higher frequencies, gradually brightening in the visible spectrum, probably over thousands if not millions of years.

Actually, reading the wikipedia article on star formation, it seems that's just about what happens. No light switch:

http://en.wikipedia.org/wiki/Stellar_evolution

As far as dust blowing away, I'm not sure how that works. I suppose it also gradually brightens as the stars output increases and the dust thins, so for a time we get a pretty reflection nebula.

by **Cobaltblu** » Tue Oct 24, 2006 3:47 pm

Wouldn't a time-lapse be great?

by **orin stepanek** » Mon Oct 23, 2006 9:28 pm

I'LL be delighted if one gets caught starting to twinkle.

I hope somebody can answer if the probability of catching one firing up is forthcoming.

Orin

by **BMAONE23** » Mon Oct 23, 2006 9:10 pm

While I don't know the answer to that, I would think that it could probably be presumed by looking at the ages of other nebula that have newly developed stars which are now visible. Unfortunately I know very little about the entire solar process, But I'll be looking foreward to see if anyone else knows the answer.

by **orin stepanek** » Mon Oct 23, 2006 8:22 pm

BMAONE23 wrote:It is possible that we may in fact live long enough to see this. It all depends on how long the accretion process takes, then the time involved for fusion to produce the winds necessary to blow the dust away from the star in sufficient quantity to make it visible to us.

How long do you think it takes for a protostar to bloom from a star nursery to a full fledged star?

Orin

by **BMAONE23** » Mon Oct 23, 2006 4:44 pm

It is possible that we may in fact live long enough to see this. It all depends on how long the accretion process takes, then the time involved for fusion to produce the winds necessary to blow the dust away from the star in sufficient quantity to make it visible to us.

by **DavidLeodis** » Mon Oct 23, 2006 4:15 pm

orin stepanek wrote:http://antwrp.gsfc.nasa.gov/apod/ap061022.html
Star eggs. Wouldn't it be fun to live long enough to see them hatch?
Orin

That made me smile. It's a lovely thought. I think they might be a bit overdone by the time we got there though! Star Trek warp speeds are needed now to give us a chance!

by **orin stepanek** » Sun Oct 22, 2006 4:13 pm

http://antwrp.gsfc.nasa.gov/apod/ap061022.html
Star eggs. Wouldn't it be fun to live long enough to see them hatch?

Orin

Starship Asterisk*

Star EGGs in the Eagle Nebula (APOD 22 Oct 2006)

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