What is this object?

[Chris Peterson]

But as you know we’re looking at a 2D image of a 3D reality. We have to imagine depth here. What if the moving star is moving at close to a right angle to our line of sight, which would make its true velocity relative to the central star close to what Art calculated, “only 73 km/s”, while the gas lobes could mostly be directed toward and away from us, so they could have velocities significantly greater than what first appearance suggests.

By the same logic, the moving star could have a much higher velocity (which is why I mentioned a minimum distance). To my eyes, this nebula appears to be viewed not too far from side-on. But I know enough not to place too much faith in my visual interpretation of images. However, given sufficient scientific interest, the radial velocity component of both the moving star and the nebular components could be reliably determined simply by examining their Doppler shifts.

[geckzilla]

That may have already been done for the nebula. Second paragraph, right column

There are possibly other papers about it that I noticed in the bibliography generated by Simbad but pay walls have a way of suddenly making me very disinterested in things.

[neufer]

I think that the [runaway star] suggestion Art raised is on target.

The process that creates planetary nebulas is not particularly violent; I don't really see a mechanism that could eject a component star in the same system (and it clearly isn't the parent star of the nebula). The only examples I know of where we have ejected stars involve supernovas, and even then are rare.

I concede that stellar mass loss events that create planetary nebulas not being all that violent is a very good point Chris, possibly even being a fatal flaw to this runaway star idea.

However, I still come back to the observational alignment of things seeming to all be radiating out from the nebula’s central star, both in apparent position and possibly also temporally as well. The alignment seems too perfect for this to be a mere coincidental alignment, IMO. As you say Chris, there’s nothing odd about the rate of this star’s motion, but if backtracking its motion leads back to the central star at the very time of the nebula’s creation, well then that would be odd, wouldn’t it?

Backtracking its motion ~700 years certainly leads close to the central star.

Perhaps it even leads back to a former close binary star system that was in orbit around the central star.

If one of those close binary stars was a white dwarf then the influx of material (from either the other binary star and/or the central star) could have resulted in a type Ia supernova that might release a ~73 km/s runaway star while having negligible effect upon the more distance central star.

If this type Ia supernova happened in the 14th century while the Sun was, itself, in Gemini
then it could well have gone unnoticed (since type Ia supernovas drop 5 magnitudes in 80 days).

That influx of material unto the former white dwarf might also
explain the unusual jets at right angles to the runaway star.

[BDanielMayfield]

Nice Art. This puts the runaway star back in the running (in my estimation).

But you’re suggesting that planetary nebula NGC 2371 is really a supernova remnant. I can imagine that idea being greeted with great skepticism.

What if, as you suggest, a pair of white dwarfs orbiting each other were also in orbit of the remaining central star and one of the dwarfs suffers a kilonova detonation. It wouldn’t have left nearly as large a remnant, and it wouldn’t be as noticeable as a Type 1a supernova blast.

Also, weren’t things still kind of dark back in the 1400’s? Many things could have gone unnoticed back then.

[neufer]

Nice Art. This puts the runaway star back in the running (in my estimation).

But you’re suggesting that planetary nebula NGC 2371 is really a supernova remnant. I can imagine that idea being greeted with great skepticism.

What if, as you suggest, a pair of white dwarfs orbiting each other were also in orbit of the remaining central star and one of the dwarfs suffers a kilonova detonation. It wouldn’t have left nearly as large a remnant, and it wouldn’t be as noticeable as a Type 1a supernova blast.

There is just a single white dwarf in my scenario. (Geckzilla's object is far too bright to be a white dwarf.)

NGC 2371 is primarily a planetary nebula of the bright (absolute magnitude ~ +2) central star.

The type Ia supernova came later and remnants like SN 1572 don't leave much behind to observe,
especially if it is mostly absorbed by the earlier planetary nebula.

Also, weren’t things still kind of dark back in the 1400’s?
Many things could have gone unnoticed back then.

Dark ages still in Europe in the 1300’s, perhaps, but there were still the Chinese & Arabs.

[makc]

Hey Chris, how'd you sneak that key-board smilie past the computer Every time i type : and add )... it gives me this

He has "Disable smilies" checked in the Options box below the full editor.

Watch me blowing your mind: :) :P (hey, 2013! as much as I like geckzilla's idea, I'm not sure I can hold myself)

[geckzilla]

Here's another one for you guys to kick around. I noticed it last week when I had some data for a nebula called Jonckheere 900. I thought it was just some random noise or artifact at first (I actually edited it out of my final picture) but today I looked at it more critically and have decided it's most likely an actual thing. What's interesting is that it's not like a star at all. It's kind of fluffy or soft looking. The temporal difference between these frames is smaller--only 3 years this time. Unfortunately it only shows up very well in the f555w data and there is only one year for that. It does show up in f658n but only just a little. Enough for me to see it moving, anyway.

First image is f555w data from 1998. Second, noisy image is f658n data from 2001. Note this is not Jonckheere 900, it's the bright star near it which tends to blend in with the nebula itself when viewed with smaller telescopes. Also note the bright white artifact across the star in the first image is just a charge bleed. Try to ignore it.

Click to view full size image 1 or image 2

[BDanielMayfield]

Thanks, but well, see, this Case 2 you’ve just offered up has a kinda nebulous (fluffy), soft, willowy and ethereal feel to it, like a wispy cloud in a powder blue sky floating on a gentle, zephyrous, breeze. This might be a wonderful topic for the Ladies at an English Tea to discuss ad nauseam, but …

In the other fist we have Case 1, which has rock-em, sock-em Action with MASSIVE MAYHEM on a COLOSSAL scale, with EXPLOSIONS and things flying out in all directions!

So, please don’t feel bad if Case 2 languishes in the cold case files geck.

It’s a guy thing.

[geckzilla]

Your lack of imagination is noted.

Edit: If you look at the whole picture it does look kind of like the fluff came from the central star of Jonckheere 900. So it did possibly originate in an EXPLOSION. Anything associated with stellar phenomena seems to carry that distinct possibility. The angle isn't quite right, though. And the fluffball is moving super fast compared to the rest of the nebula.

Here's a wider field of view. I avoided it earlier because the nebula itself looks way different between filters and that's pretty distracting. Anyway, the fluffball seems to point at that faint star in the upper left. But when we are looking at space it's only a matter of time before any given ray intersects a star.

Click to view full size image 1 or image 2

[BDanielMayfield]

Lack of imagination?

Yes, everything in space is the product of one or more explosions, which is part of why we (guys) love astronomy. The gals are drawn in by the beauty of what the explosions create. {I know, that’s a gender oversimplification, but it’s crudely true, I think. But I’m crude.}

Yes, Case 2 does have the redeeming quality of hyper-velocity, but ...

We haven’t closed the book on Case 1 yet. Chris was able to effectively poke holes in my amateurish imaginings, but he hasn’t yet remarked on Neufer’s 1a supernova scenario. Is his suggestion plausible Chris?

[geckzilla]

And here I thought we were all after the mysteries, not the explosions or pretty pictures. A pretty picture may draw me in initially but it's definitely curiosity and the how's and why's that keep me going.

[makc]

not the explosions or pretty pictures

ahem... what?? this is apod forum. it was always about pretty pictures. and explosions.

[Beyond]

And explosions

Explosions? like this?

[BDanielMayfield]

And here I thought we were all after the mysteries, not the explosions or pretty pictures. A pretty picture may draw me in initially but it's definitely curiosity and the how's and why's that keep me going.

We are all in it for the mysteries, now. All I meant was that what gets us interested in the first place differs somewhat, which I wanted to say in an amusing way.

I must say however that Case 2 has become more interesting since you added the photos of the main nebula Geckzilla.

And explosions

Explosions? like this?

Shame on you Beyond. You know better than that! The cause of THAT explosion is hardly an unknown. Hopefully we all prefer natural explosions here. It’s time to “beat swords into plowshares”.

[geckzilla]

All I meant was that what gets us interested in the first place differs somewhat, which I wanted to say in an amusing way.

You may have been joking but gender roles are so contrived and I'm not sure awe of the cosmos is affected by it. It would be interesting to see the results of a poll on the subject.

[Beyond]

And explosions

Explosions? like this?

Shame on you Beyond. You know better than that! The cause of THAT explosion is hardly an unknown. Hopefully we all prefer natural explosions here. It’s time to “beat swords into plowshares”.

Hey, there's no 'shame' in liking pretty big pictures of mushrooms.
I don't know why fissionable material acts like THAT, so it's unknown to me. Perhaps you'd like to splain the difference between man's atomic and thermo-nuclear explosions and the "natural" explosions you are referring to

[BDanielMayfield]

Hey, there's no 'shame' in liking pretty big pictures of mushrooms.

Dr. Strangelike, I presume? What you may find “pretty” many others may find appalling, due to the danger it represents, and due to the pain and suffering the use and even the testing of such weapons have caused. I’m sorry to be so critical Beyond, because I know you were just being jovial, as was I. I hope this doesn’t drive a rift between us, but I do regret that you posted that clip.

I don't know why fissionable material acts like THAT, so it's unknown to me.

Fissionable material, after being assembled in combination with fusible material, can act like that because man has learned how to release a small fraction of the enormous energy locked up in atoms. It’s a very good thing that more of the world’s nations and fanatical groups haven’t learned how to do this.

Perhaps you'd like to splain the difference between man's atomic and thermo-nuclear explosions and the "natural" explosions you are referring to

Man’s thermo-nuclear explosions are destructive, even if it’s only a just a test. Natural explosions are constructive, and we wouldn’t be here without them. But mankind’s nuclear weapons of mass destruction would be the end of life as we know it if they were ever fully used. Even limited use would be horrendous.

I hope the time comes soon when mankind will ‘learn war no more.’ (Isaiah 2:4)

[Beyond]

Hmm... I guess you've never been in the vicinity of any kind of nova.
An explosion is an explosion. They come in many sizes. I like the way some of them look, both man-made and what you call natural. What you call 'natural' are vastly more destructive than anything man can make and for the most part, look vastly better also.

No worries, Bruce, no rift. And besides, I'm not the one who introduced "case #1". I just added a very tiny, itsy-bitsy man sized example.

[makc]

What you may find “pretty” many others may find appalling, due to the danger it represents, and due to the pain and suffering the use and even the testing of such weapons have caused.

All of those people enjoying cars and planes and whatever else crashing and blowing up in hollywood movies are probably latent pyromaniacs.

[neufer]

Click to play embedded YouTube video.

Click to play embedded YouTube video.

[Beyond]

Gee, Art, Mondays are depressing enough on their own.

[makc]

let me balance it a bit:

Click to play embedded YouTube video.

[Beyond]

Gee, makc, Mondays are weird enough all on their own.

[BDanielMayfield]

This was a real interesting thread for a while, but then it bombed.

[geckzilla]

Just a star which happens to be brighter in one picture. There aren't a whole lot of images in the HLA which are exact repeats of filters and exposure times but this is one of them. I cleaned up a couple of cosmic rays so they wouldn't be distracting.

Click to view full size image 1 or image 2

NGC6578_star_1995.jpg (35.91 KiB) Viewed 23167 times

NGC6578_star_1999.jpg (36.03 KiB) Viewed 23167 times