Starship Asterisk*

neufer wrote:

starsurfer wrote:
Some examples of PN with jets:

1. Fg 1
2. Necklace Nebula
3. ETHOS 1

APOD Robot wrote: The Necklace Nebula

Explanation: The small constellation Sagitta sports this large piece of cosmic jewelry, dubbed the Necklace Nebula. The newly discovered example of a ring-shaped planetary nebula is about 15,000 light-years distant. Its bright ring with pearls of glowing gas is half a light-year across. Planetary nebulae are created by sun-like stars in a final phase of stellar evolution. But the Necklace Nebula's central star, near the center of a ring strongly tilted to our line of sight, has also been shown to be binary, a close system of two stars with an orbital period of just over a day. Astronomers estimating the apparent age of the ring to be around 5,000 years, also find more distant gas clouds perpendicular to the ring plane, seen here at the upper left and lower right. Those clouds were likely ejected about 5,000 years before the clouds forming the necklace. This false color image combines emission from ionized hydrogen in blue, oxygen in green, and nitrogen in red. >>

https://en.wikipedia.org/wiki/Necklace_Nebula wrote:

[b][color=#0000FF]Necklace Nebula, from Hubble Space Telescope, July 2, 2011. Hubble's Wide Field Camera 3 captured the glow of hydrogen (blue), oxygen (green), and nitrogen (red).[/color][/b]

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<<The Necklace Nebula (PN G054.2-03.4) is a 2 light-year-wide) planetary nebula located about 15,000 light-years away in the northern constellation Sagitta. It was discovered in 2005 from the Isaac Newton Telescope Photometric H-alpha Survey (IPHAS), a ground-based H-alpha planetary nebula study of the North Galactic Plane.

The Necklace Nebula is the exploded aftermath of a giant star that came too close to its Sun-like binary companion. The two stars that produced the Necklace Nebula are in a relatively small orbit about each other. They have a period of 1.2 days and a separation on the order of 5 times the radius of the Sun.

About 10,000 years ago one of the aging stars ballooned to the point where it engulfed its companion star. The smaller star continued orbiting inside its larger companion, increasing the giant’s rotation rate. The bloated companion star spun so fast that a large part of its gaseous envelope expanded into space. Due to centrifugal force, most of the gas escaped along the star’s equator, producing a ring. The embedded bright knots are dense gas clumps in the ring.>>

Chris Peterson wrote:

starsurfer wrote:

Chris Peterson wrote: If you say so. All I can say is that I have not ever seen an example of a PN that appears to have jets. Not that they don't or can't exist.

Some examples of PN with jets:

1. Fg 1
2. Necklace Nebula
3. ETHOS 1

Thanks! Those are the sort of examples I was looking for.

My conclusion is that PNs with jets are extremely rare, but when we see the PNs very early in their development we may encounter them.

starsurfer wrote:
Some examples of PN with jets:

1. Fg 1
2. Necklace Nebula
3. ETHOS 1

APOD Robot wrote: The Necklace Nebula

Explanation: The small constellation Sagitta sports this large piece of cosmic jewelry, dubbed the Necklace Nebula. The newly discovered example of a ring-shaped planetary nebula is about 15,000 light-years distant. Its bright ring with pearls of glowing gas is half a light-year across. Planetary nebulae are created by sun-like stars in a final phase of stellar evolution. But the Necklace Nebula's central star, near the center of a ring strongly tilted to our line of sight, has also been shown to be binary, a close system of two stars with an orbital period of just over a day. Astronomers estimating the apparent age of the ring to be around 5,000 years, also find more distant gas clouds perpendicular to the ring plane, seen here at the upper left and lower right. Those clouds were likely ejected about 5,000 years before the clouds forming the necklace. This false color image combines emission from ionized hydrogen in blue, oxygen in green, and nitrogen in red. >>

https://en.wikipedia.org/wiki/Necklace_Nebula wrote:

[b][color=#0000FF]Necklace Nebula, from Hubble Space Telescope, July 2, 2011. Hubble's Wide Field Camera 3 captured the glow of hydrogen (blue), oxygen (green), and nitrogen (red).[/color][/b]

---

<<The Necklace Nebula (PN G054.2-03.4) is a 2 light-year-wide) planetary nebula located about 15,000 light-years away in the northern constellation Sagitta. It was discovered in 2005 from the Isaac Newton Telescope Photometric H-alpha Survey (IPHAS), a ground-based H-alpha planetary nebula study of the North Galactic Plane.

The Necklace Nebula is the exploded aftermath of a giant star that came too close to its Sun-like binary companion. The two stars that produced the Necklace Nebula are in a relatively small orbit about each other. They have a period of 1.2 days and a separation on the order of 5 times the radius of the Sun.

About 10,000 years ago one of the aging stars ballooned to the point where it engulfed its companion star. The smaller star continued orbiting inside its larger companion, increasing the giant’s rotation rate. The bloated companion star spun so fast that a large part of its gaseous envelope expanded into space. Due to centrifugal force, most of the gas escaped along the star’s equator, producing a ring. The embedded bright knots are dense gas clumps in the ring.>>

starsurfer wrote:

Chris Peterson wrote:

neufer wrote: A non-degenerate Planetary Nebula Nucleus (PNN) itself
which must (slowly) collapse into a degenerate white dwarf.

If you say so. All I can say is that I have not ever seen an example of a PN that appears to have jets. Not that they don't or can't exist.

Some examples of PN with jets:

1. Fg 1
2. Necklace Nebula
3. ETHOS 1

Chris Peterson wrote:

neufer wrote:

Chris Peterson wrote:
What inflowing material do we see in any planetary nebulas?

A non-degenerate Planetary Nebula Nucleus (PNN) itself
which must (slowly) collapse into a degenerate white dwarf.

If you say so. All I can say is that I have not ever seen an example of a PN that appears to have jets. Not that they don't or can't exist.

neufer wrote:

Chris Peterson wrote:
What inflowing material do we see in any planetary nebulas?

A non-degenerate Planetary Nebula Nucleus (PNN) itself
which must (slowly) collapse into a degenerate white dwarf.

Chris Peterson wrote:
What inflowing material do we see in any planetary nebulas?

neufer wrote:Supersonic material is the last to arrive and it cannot maintain itself forever with no current source.

neufer wrote:

Chris Peterson wrote:

neufer wrote:
there seems to be no reason to believe:

• 2) that the Planetary Nebula Nucleus (PNN) morphing/collapsing into a white dwarf
  doesn't emulate Herbig–Haro (HH) active jets: http://apod.nasa.gov/apod/ap151218.html

I don't know what you mean by that.

A Planetary Nebula Nucleus (PNN) collapsing into a white dwarf should probably have:

• 1) the magnetic field strength,
  2) the rotation rate and
  3) the inflowing material flux

to produce jets.

Chris Peterson wrote:

neufer wrote:
there seems to be no reason to believe:

• 1) that the FLIERs are not the product of active jets and

No? Sorry, I see nothing to make be think that these are the product of active jets. There appears to be no material coming from the central star, just material ejected at high velocity very early in the formation of the PN. Certainly, that ejection may have been related to some sort of jet phenomenon, but that doesn't mean that the FLIER is a jet.[/list]

• 1) maintaining a supersonic shockwave and/or
  2) moving at a doppler measured supersonic speed.

Chris Peterson wrote:

neufer wrote:
there seems to be no reason to believe:

• 2) that the Planetary Nebula Nucleus (PNN) morphing/collapsing into a white dwarf
  doesn't emulate Herbig–Haro (HH) active jets: http://apod.nasa.gov/apod/ap151218.html

I don't know what you mean by that.

• 1) the magnetic field strength,
  2) the rotation rate and
  3) the inflowing material flux

neufer wrote:

Chris Peterson wrote:

neufer wrote:

Yes. So what in this makes you think they are the product of active jets? That's not my interpretation.

Well...it certainly doesn't just involve "material produced very early in the gas shell ejection process."

And there seems to be no reason to believe:

• 1) that the FLIERs are not the product of active jets and

2) that the Planetary Nebula Nucleus (PNN) morphing/collapsing into a white dwarf
doesn't emulate Herbig–Haro (HH) active jets: http://apod.nasa.gov/apod/ap151218.html[/list]

Chris Peterson wrote:

neufer wrote:

Chris Peterson wrote:
I don't see any evidence of that, and the descriptions of FLIERs that are presented in the literature don't seem to suggest that they are anything but material produced very early in the gas shell ejection process. Have you seen something that argues otherwise?

https://en.wikipedia.org/wiki/Fast_Low-Ionization_Emission_Region wrote:
<<A Fast Low-Ionization Emission Region, or FLIER, is a volume of gas with low ionization, moving at supersonic speeds, near the symmetry axis of many planetary nebulae. Their outflow speeds are significantly higher than the nebulae in which they are embedded, and their ionizations are much lower. FLIERs' high speeds suggest ages much younger than their parent nebulae, and their low ionizations indicate that the ultraviolet radiation that ionizes the gas around them does not penetrate into the FLIERs.>>

Yes. So what in this makes you think they are the product of active jets? That's not my interpretation.

• 1) that the FLIERs are not the product of active jets and
  
  2) that the Planetary Nebula Nucleus (PNN) morphing/collapsing into a white dwarf
  doesn't emulate Herbig–Haro (HH) active jets: http://apod.nasa.gov/apod/ap151218.html

neufer wrote:

Chris Peterson wrote:

neufer wrote: You said that FLIERs aren't jets...because..."jets are active phenomena."

How do you know that FLIERs aren't "active phenomena"
(; e.g., the interaction of polar jets with planetary nebula) :?:

I don't see any evidence of that, and the descriptions of FLIERs that are presented in the literature don't seem to suggest that they are anything but material produced very early in the gas shell ejection process. Have you seen something that argues otherwise?

https://en.wikipedia.org/wiki/Fast_Low-Ionization_Emission_Region wrote:
<<A Fast Low-Ionization Emission Region, or FLIER, is a volume of gas with low ionization, moving at supersonic speeds, near the symmetry axis of many planetary nebulae. Their outflow speeds are significantly higher than the nebulae in which they are embedded, and their ionizations are much lower. FLIERs' high speeds suggest ages much younger than their parent nebulae, and their low ionizations indicate that the ultraviolet radiation that ionizes the gas around them does not penetrate into the FLIERs.>>

Chris Peterson wrote:

neufer wrote:

Chris Peterson wrote:
What I said is that FLIERs aren't jets.

You said that FLIERs aren't jets...because..."jets are active phenomena."

How do you know that FLIERs aren't "active phenomena"
(; e.g., the interaction of polar jets with planetary nebula)

I don't see any evidence of that, and the descriptions of FLIERs that are presented in the literature don't seem to suggest that they are anything but material produced very early in the gas shell ejection process. Have you seen something that argues otherwise?

https://en.wikipedia.org/wiki/Fast_Low-Ionization_Emission_Region wrote:
<<A Fast Low-Ionization Emission Region, or FLIER, is a volume of gas with low ionization, moving at supersonic speeds, near the symmetry axis of many planetary nebulae. Their outflow speeds are significantly higher than the nebulae in which they are embedded, and their ionizations are much lower. FLIERs' high speeds suggest ages much younger than their parent nebulae, and their low ionizations indicate that the ultraviolet radiation that ionizes the gas around them does not penetrate into the FLIERs.>>

neufer wrote:

Chris Peterson wrote:
What I said is that FLIERs aren't jets.

You said that FLIERs aren't jets...because..."jets are active phenomena."

How do you know that FLIERs aren't "active phenomena"
(; e.g., the interaction of polar jets with planetary nebula) :?:

Chris Peterson wrote:
What I said is that FLIERs aren't jets.

neufer wrote:

Chris Peterson wrote:I would not, however, remotely consider FLIERs to be jets of some sort. They're merely residual structure from the process that ejected the gaseous shell. Jets are active phenomena.

You have no problem with a white dwarf producing active jets: http://asterisk.apod.com/viewtopic.php?f=31&t=36201
or Herbig–Haro (HH) active jets: http://apod.nasa.gov/apod/ap151218.html

...but a Planetary Nebula Nucleus (PNN) morphing/collapsing into a white dwarf
(or a Planetary Nebula Nucleus (PNN) companion white dwarf): http://asterisk.apod.com/viewtopic.php? ... 01#p260405

...cannot "remotely" produce active jets :?:

Chris Peterson wrote:

neufer wrote:

geckzilla wrote:
There are features that some planetary nebulas have known as FLIERs
that might be related to some kind of short-lived jet-like action.

• . http://apod.nasa.gov/apod/ap051029.html
  . http://apod.nasa.gov/apod/ap010526.html
  . http://apod.nasa.gov/apod/ap971021.html
  . http://apod.nasa.gov/apod/ap961122.html

https://en.wikipedia.org/wiki/NGC_6826 wrote:
<<Their outflow speeds are significantly higher than the nebulae in which they are embedded, and their ionizations are much lower. FLIERs' high speeds suggest ages much younger than their parent nebulae, and their low ionizations indicate that the ultraviolet radiation that ionizes the gas around them does not penetrate into the FLIERs.>>

I would not, however, remotely consider FLIERs to be jets of some sort. They're merely residual structure from the process that ejected the gaseous shell. Jets are active phenomena.

neufer wrote:

geckzilla wrote: There are features that some planetary nebulas have known as FLIERs
that might be related to some kind of short-lived jet-like action.

• . http://apod.nasa.gov/apod/ap051029.html
  . http://apod.nasa.gov/apod/ap010526.html
  . http://apod.nasa.gov/apod/ap971021.html
  . http://apod.nasa.gov/apod/ap961122.html

https://en.wikipedia.org/wiki/NGC_6826 wrote:

geckzilla wrote:
There are features that some planetary nebulas have known as FLIERs
that might be related to some kind of short-lived jet-like action.

• . http://apod.nasa.gov/apod/ap051029.html
  . http://apod.nasa.gov/apod/ap010526.html
  . http://apod.nasa.gov/apod/ap971021.html
  . http://apod.nasa.gov/apod/ap961122.html

https://en.wikipedia.org/wiki/NGC_6826 wrote:

[b][color=#0000FF]Hubble Space Telescope (HST) image of NGC 6826.[/color][/b]

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<<NGC 6826 (also known as Caldwell 15) is a planetary nebula located in the constellation Cygnus. It is commonly referred to as the "blinking planetary", although many other nebulae exhibit such "blinking". When viewed through a small telescope, the brightness of the central star overwhelms the eye when viewed directly, obscuring the surrounding nebula. However, it can be viewed well using averted vision, which causes it to "blink" in and out of view as the observer's eye wanders.

A distinctive feature of this nebula are the two bright patches on either side, which are known as Fast Low-Ionization Emission Regions, or FLIERS. They appear to be relatively young, moving outwards at supersonic speeds, near the symmetry axis. Their outflow speeds are significantly higher than the nebulae in which they are embedded, and their ionizations are much lower. FLIERs' high speeds suggest ages much younger than their parent nebulae, and their low ionizations indicate that the ultraviolet radiation that ionizes the gas around them does not penetrate into the FLIERs.>>

Ann wrote:

Chris Peterson wrote:

starsurfer wrote: Jets in planetary nebulae usually arise from an accretion disk around the central star. Also some planetary nebulae are known to have OIII blobs at the outer edges visible in deep images, so I guess these might be high excitation?

Well, it's a big universe and there's a lot of stuff out there, but are there planetary nebulas where their central stars have accretion discs? I can't think of any, and it isn't clear to me how that could even happen. Planetary nebulas are just the glow of ejected gas from late-state, lower mass stars which are hot enough to ionize that gas. Isotropically hot, no stellar structure, no stellar jets, just 30,000 K blackbodies.

HEIC/ESO has just reported about a white dwarf star with a jet.

Are these "fully developed" white dwarf stars different from the central stars of planetary nebulas? Or is it true after all that the central stars of planetary nebulas can have jets?

Chris Peterson wrote:

starsurfer wrote:

Chris Peterson wrote:Do you know of any planetary nebulas that show anything at all coming from the star?

Jets in planetary nebulae usually arise from an accretion disk around the central star. Also some planetary nebulae are known to have OIII blobs at the outer edges visible in deep images, so I guess these might be high excitation?

Well, it's a big universe and there's a lot of stuff out there, but are there planetary nebulas where their central stars have accretion discs? I can't think of any, and it isn't clear to me how that could even happen. Planetary nebulas are just the glow of ejected gas from late-state, lower mass stars which are hot enough to ionize that gas. Isotropically hot, no stellar structure, no stellar jets, just 30,000 K blackbodies.

starsurfer wrote:

Chris Peterson wrote:Do you know of any planetary nebulas that show anything at all coming from the star?

Jets in planetary nebulae usually arise from an accretion disk around the central star. Also some planetary nebulae are known to have OIII blobs at the outer edges visible in deep images, so I guess these might be high excitation?

Chris Peterson wrote:Do you know of any planetary nebulas that show anything at all coming from the star?

geckzilla wrote:I do think it is highly likely that Abell 39 is a sphere or close to spherical shell.