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APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 4:05 am
by APOD Robot
The Red Square Nebula
Explanation: How did a round star create this square nebula? No one is quite sure. The round star, known as MWC 922 and possibly part of a
multiple star system, appears at the center of the
Red Square Nebula. The
featured image combines
infrared exposures from the
Hale Telescope on
Mt. Palomar in
California, and the
Keck-2 Telescope on
Mauna Kea in
Hawaii. A leading progenitor hypothesis for the
square nebula is that the central
star or stars somehow expelled cones of gas during a late
developmental stage. For
MWC 922, these cones happen to incorporate nearly
right angles and be visible from the sides. Supporting evidence for the
cone hypothesis includes radial spokes in the image that might run along the
cone walls. Researchers speculate that the
cones viewed from another angle would appear similar to the gigantic rings of
supernova 1987A, possibly indicating that a star in MWC 922 might one day itself explode in a similar
supernova.
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 5:38 am
by Ann
Red red red. Square square square. ██ ██ ██
I feel like a little bird chirping. 🦜
Although I guess that's a parrot, so I guess he's saying:
Red red red. Square square square. You're square.
Yes, I'm sure that's what he's saying, in parrot speak.
Ann
No, I couldn't be more serious today.
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 8:01 am
by madtom1999
A red cross /crucifix in AD 773/4/6 was mentioned in the Anglo-Saxon Chronicle, I've always thought it must be one of these.
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 9:04 am
by Tedheubach
Magnetism... I'll go for magnetism... field lines of a multiple star system!
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 12:10 pm
by orin stepanek
I tipped it to fit my screen!
![Wink :wink:](./images/smilies/icon_wink.gif)
Weird color and shape; for a nebula;
but it really looks nice!
Kitty helping doggie feel better! 🥰
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 1:29 pm
by Chris Peterson
Tedheubach wrote: ↑Sun Sep 26, 2021 9:04 am
Magnetism... I'll go for magnetism... field lines of a multiple star system!
Magnetic fields around star systems are far too weak to produce structures like this.
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 1:50 pm
by j_isles
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 3:36 pm
by bungi
Looks more like a diffraction pattern to me. Though what could be diffracting it I hesitate to guess. Perhaps it's gravitational.
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 3:48 pm
by Chris Peterson
bungi wrote: ↑Sun Sep 26, 2021 3:36 pm
Looks more like a diffraction pattern to me. Though what could be diffracting it I hesitate to guess. Perhaps it's gravitational.
Definitely not diffraction. The structure is real.
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 7:22 pm
by johnnydeep
Neat! To my naive eye, it looks quite similar in fine structure detail to the Red Square Nebula, perhaps confirming a similar formation mechanism. Now, show me a Red Triangle Nebula !
![:) :ssmile:](./images/smilies/smile.gif)
Hmm, I wonder if that would be more or less explainable than a Red Hexagon Nebula...
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 8:20 pm
by neufer
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 8:28 pm
by johnnydeep
I'll give that a B+ for effort.
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Sun Sep 26, 2021 9:22 pm
by daddyo
The cones seem to have maybe 4 periodic events/episodes to them
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Mon Sep 27, 2021 3:48 am
by VictorBorun
Chris Peterson wrote: ↑Sun Sep 26, 2021 1:29 pm
Tedheubach wrote: ↑Sun Sep 26, 2021 9:04 am
Magnetism... I'll go for magnetism... field lines of a multiple star system!
Magnetic fields around star systems are far too weak to produce structures like this.
what if the thing was magnetic at first, at its stellar Big Bang, and inertial cones* ever after?
*Of course we can't tell a pair of lines (=walls of a bicone) from a hyperbola (=walls of hyperboloid) when we can't see details near the crosspoint of the pair of lines or the pair of asymptotes…
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Mon Sep 27, 2021 4:05 am
by Chris Peterson
VictorBorun wrote: ↑Mon Sep 27, 2021 3:48 am
Chris Peterson wrote: ↑Sun Sep 26, 2021 1:29 pm
Tedheubach wrote: ↑Sun Sep 26, 2021 9:04 am
Magnetism... I'll go for magnetism... field lines of a multiple star system!
Magnetic fields around star systems are far too weak to produce structures like this.
what if the thing was magnetic at first, at its stellar Big Bang, and inertial cones* ever after?
*Of course we can't tell a pair of lines (=walls of a bicone) from a hyperbola (=walls of hyperboloid) when we can't see details near the crosspoint of the pair of lines or the pair of asymptotes…
Stars have magnetic fields, and the nature of their magnetic environment when they blow off their atmospheres almost certainly factors into the final structure.
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Mon Sep 27, 2021 9:11 am
by bungi
Chris Peterson wrote: ↑Sun Sep 26, 2021 3:48 pm
bungi wrote: ↑Sun Sep 26, 2021 3:36 pm
Looks more like a diffraction pattern to me. Though what could be diffracting it I hesitate to guess. Perhaps it's gravitational.
Definitely not diffraction. The structure is real.
your evidence please. I'm curious how you are so sure this is not at least partly optical.
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Mon Sep 27, 2021 1:18 pm
by Chris Peterson
bungi wrote: ↑Mon Sep 27, 2021 9:11 am
Chris Peterson wrote: ↑Sun Sep 26, 2021 3:48 pm
bungi wrote: ↑Sun Sep 26, 2021 3:36 pm
Looks more like a diffraction pattern to me. Though what could be diffracting it I hesitate to guess. Perhaps it's gravitational.
Definitely not diffraction. The structure is real.
your evidence please. I'm curious how you are so sure this is not at least partly optical.
Yours is the extraordinary claim; yours is the burden to provide evidence. "Looks like" doesn't cut it. What possible mechanism exists that could diffract light in this way? And keep in mind, this object has been examined at multiple wavelengths, spectroscopically, and probably other ways, as well. And that similar planetary nebulas are known.
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Mon Sep 27, 2021 2:20 pm
by VictorBorun
bungi wrote: ↑Mon Sep 27, 2021 9:11 am
Chris Peterson wrote: ↑Sun Sep 26, 2021 3:48 pm
bungi wrote: ↑Sun Sep 26, 2021 3:36 pm
Looks more like a diffraction pattern to me. Though what could be diffracting it I hesitate to guess. Perhaps it's gravitational.
Definitely not diffraction. The structure is real.
your evidence please. I'm curious how you are so sure this is not at least partly optical.
if you mean diffraction spikes in a reflection telescope with some non-circular the second mirror's holders, then consider how easy it is to tune those spikes off by rotating your telescope around its optical axis or switching to a telescope with a different number of the second mirror's holders
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Mon Sep 27, 2021 2:22 pm
by Chris Peterson
VictorBorun wrote: ↑Mon Sep 27, 2021 2:20 pm
bungi wrote: ↑Mon Sep 27, 2021 9:11 am
Chris Peterson wrote: ↑Sun Sep 26, 2021 3:48 pm
Definitely not diffraction. The structure is real.
your evidence please. I'm curious how you are so sure this is not at least partly optical.
if you mean diffraction spikes in a reflection telescope with some non-circular the second mirror's holders, then consider how easy it is to tune those spikes off by rotating your telescope around its optical axis or switching to a telescope with a different number of the second mirror's holders
I took the suggestion to be that some mysterious and undefined mechanism at the source or between the source and us was creating diffraction (that just happens to look like the diffraction we see from a telescope with square aperture or a four-armed secondary support). Of course, no such mechanism is known.
Re: APOD: The Red Square Nebula (2021 Sep 26)
Posted: Mon Sep 27, 2021 7:38 pm
by neufer
APOD Robot wrote: ↑Sun Sep 26, 2021 4:05 am
Explanation: A leading progenitor hypothesis for the
square nebula is that the central
star or stars somehow expelled cones of gas during a late
developmental stage. For
MWC 922, these cones happen to incorporate nearly
right angles and be visible from the sides. Supporting evidence for the
cone hypothesis includes radial spokes in the image that might run along the
cone walls. Researchers speculate that the
cones viewed from another angle would appear similar to the gigantic rings of
supernova 1987A, possibly indicating that a star in MWC 922 might one day itself explode in a similar
supernova.
- One wonders why they don't take a spectrum through the middle of the cones
in search of a Doppler line split between opposite sides of the cone wall.