ASTRO: McNeil's Nebula February 2010 and Oct. 2008

This new nebula, first recognized by Jay McNeil when trying out a new 3"
telescope in 2004 has interested me. It's appearance was short lived as
by 2005 it was gone. An amateur photo by Evered Kreimer in 1966 shows
it but DSS images taken before and after this date don't. When I finally
got the observatory up and running in 2005 it was gone as mentioned.
Figuring I likely had 40 years before it would reappear I crossed it off
my list but kept hoping it would return. When it came out of the sun's
glare in August of 2008 it was back! Since then I've kept watch on it
though it seems not to be well followed by the amateur community for
some reason.

Images I took in September then again in late October of 2008 showed it
had changed somewhat from its previous appearance. This image is taken
in February 2010. Unfortunately my color data was hampered by severe
clouds. They dimmed the overall image somewhat but seeing was far
better. This makes comparing the two difficult but it appears there's
little change over this period. There appears to be a faint spur coming
out of the bottom right of the nebula that is lost in the bright region
to its left in the 2008 image but is barely seen. This may be a seeing
effect.

McNeil's Nebula is thought to be a brand new star shedding the dust
cloud that surrounded it's formation. As the cloud is blown away it
allows the light to hit and reflect from dust to its north. In this
case both the star and nebula become visible at the same time.

Below the nebula, thanks to my different orientation are some new other
very new stars. The group of four red objects below McNeil's nebula are
Herbig Haro objects HH24a-d. These are also new stars. In this case
they are creating high speed jets out their rotational axes that hit
nearby gas and dust. The red comes from hydrogen alpha emissions
created by hydrogen gas hit by the jet. Such objects are thought to
last only a very few thousand of years being a short phase in the birth
of a star.

Further south is another cloud, most seen by reflection. It is lit by
the light of the T Tauri star HGC 502. These likely are somewhat
"older" new stars, being a million years old or so. They are still not
on the main sequence and vary in intensity. They often are lighting up
the dust and gas that surrounds their birth site. Since they vary in
intensity as they get their fusion cores under control as they move onto
the main sequence where they will spend most of their lives, the nebula
also varies in intensity. Since light travels at a finite speed the
star and nebula appear to vary independently of each other. This is due
to the light travel times involved due to the geometry of their location
and ours.

So where does McNeil's nebula fit in? It is likely an FU Orionis Star.
These too are stars still in their infancy that haven't reached the
main sequence as yet. They are known for "rapid" brightening of several
magnitudes, often staying very bright for years at a time. But "rapid"
only in the astronomical sense. They can take only months or decades to
brighten. The range is quite great. Since the brightening has always
happened when no one is looking both the nebula and star are at full
brightness. It should be that they brighten somewhat differently as the
light from the star has to travel the length of the nebula and has to
then come to us. Thus it should brighten with the parts closest to the
star being seen first. Yet this isn't seen. It could be the nebula is
like a pencil pointed almost at us such that the light from the star
lights it up as the light heads toward us resulting in us seeing it
light all at once. That's about all I can think of.

I haven't yet taken it for this season. I hope to soon however. I did
grab one good 10 minute luminance shot before clouds got me a few weeks
ago and it appears very similar to what is seen here.

Above McNeil's nebula is a somewhat larger reflection nebula, NGC 2064.
The huge reflection nebula is M78, probably the brightest reflection
nebula known.

14" LX200R @ f/10, L=4x10' RG=2x10'x3 B=3x10'x3, STL-11000XM, Paramount ME

First attached image is the February 2010 image, second the October 2008
image. The former has far better seeing the latter far better
transparency. Why do these seem to obey the Heisenberg Principle?

Rick
--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

Rick,

great detail and thanks for the update on what McNeil's nebula is (I think I
messed up that sentence, but that's how you would say it in german if you
wanted to use english vocabulary ;-)
I have imaged this nebula after Jay posted the discovery here, but M78 is
still on my list for a decent shot.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
ter.com...
This new nebula, first recognized by Jay McNeil when trying out a new 3"
telescope in 2004 has interested me. It's appearance was short lived as
by 2005 it was gone. An amateur photo by Evered Kreimer in 1966 shows
it but DSS images taken before and after this date don't. When I finally
got the observatory up and running in 2005 it was gone as mentioned.
Figuring I likely had 40 years before it would reappear I crossed it off
my list but kept hoping it would return. When it came out of the sun's
glare in August of 2008 it was back! Since then I've kept watch on it
though it seems not to be well followed by the amateur community for
some reason.

Images I took in September then again in late October of 2008 showed it
had changed somewhat from its previous appearance. This image is taken
in February 2010. Unfortunately my color data was hampered by severe
clouds. They dimmed the overall image somewhat but seeing was far
better. This makes comparing the two difficult but it appears there's
little change over this period. There appears to be a faint spur coming
out of the bottom right of the nebula that is lost in the bright region
to its left in the 2008 image but is barely seen. This may be a seeing
effect.

McNeil's Nebula is thought to be a brand new star shedding the dust
cloud that surrounded it's formation. As the cloud is blown away it
allows the light to hit and reflect from dust to its north. In this
case both the star and nebula become visible at the same time.

Below the nebula, thanks to my different orientation are some new other
very new stars. The group of four red objects below McNeil's nebula are
Herbig Haro objects HH24a-d. These are also new stars. In this case
they are creating high speed jets out their rotational axes that hit
nearby gas and dust. The red comes from hydrogen alpha emissions
created by hydrogen gas hit by the jet. Such objects are thought to
last only a very few thousand of years being a short phase in the birth
of a star.

Further south is another cloud, most seen by reflection. It is lit by
the light of the T Tauri star HGC 502. These likely are somewhat
"older" new stars, being a million years old or so. They are still not
on the main sequence and vary in intensity. They often are lighting up
the dust and gas that surrounds their birth site. Since they vary in
intensity as they get their fusion cores under control as they move onto
the main sequence where they will spend most of their lives, the nebula
also varies in intensity. Since light travels at a finite speed the
star and nebula appear to vary independently of each other. This is due
to the light travel times involved due to the geometry of their location
and ours.

So where does McNeil's nebula fit in? It is likely an FU Orionis Star.
These too are stars still in their infancy that haven't reached the
main sequence as yet. They are known for "rapid" brightening of several
magnitudes, often staying very bright for years at a time. But "rapid"
only in the astronomical sense. They can take only months or decades to
brighten. The range is quite great. Since the brightening has always
happened when no one is looking both the nebula and star are at full
brightness. It should be that they brighten somewhat differently as the
light from the star has to travel the length of the nebula and has to
then come to us. Thus it should brighten with the parts closest to the
star being seen first. Yet this isn't seen. It could be the nebula is
like a pencil pointed almost at us such that the light from the star
lights it up as the light heads toward us resulting in us seeing it
light all at once. That's about all I can think of.

I haven't yet taken it for this season. I hope to soon however. I did
grab one good 10 minute luminance shot before clouds got me a few weeks
ago and it appears very similar to what is seen here.

Above McNeil's nebula is a somewhat larger reflection nebula, NGC 2064.
The huge reflection nebula is M78, probably the brightest reflection
nebula known.

14" LX200R @ f/10, L=4x10' RG=2x10'x3 B=3x10'x3, STL-11000XM, Paramount ME

First attached image is the February 2010 image, second the October 2008
image. The former has far better seeing the latter far better
transparency. Why do these seem to obey the Heisenberg Principle?

Rick
--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

Interesting that you should mention this nebula, as I took an image of M78
on December 8 of this month.

Image:

10x5 minutes for a total of 50 minutes at ISO 1600
Stacked in DeepSkyStacker, Dark Subtracted
Processed in Adobe Photoshop CS3 Extended
Taken on December 8, 2010 at the Louisville Astronomical Society
Observatory, in Curby, Indiana

Equipment:

200 mm f5 Konus Newtonian with Baader coma corrector and UV/IR cut filter
Hutech Canon T1i DSLR
Losmandy G11 Gemini GOTO mount on Heavy Duty Tripod
Orion Shorty Autoguide Scope with Starshooter autoguider: