APOD: The Red Square Nebula (2021 Sep 26)

[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.

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[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.

Click to play embedded YouTube video.

Ann

No, I couldn't be more serious today.

[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.

[Tedheubach]

Magnetism... I'll go for magnetism... field lines of a multiple star system!

[orin stepanek]

I tipped it to fit my screen! Weird color and shape; for a nebula;
but it really looks nice!

Kitty helping doggie feel better! 🥰

[Chris Peterson]

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.

[j_isles]

Not to be confused with the Red Rectangle!
https://en.wikipedia.org/wiki/Red_Rectangle_Nebula

John

[bungi]

Looks more like a diffraction pattern to me. Though what could be diffracting it I hesitate to guess. Perhaps it's gravitational.

[Chris Peterson]

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.

[johnnydeep]

Not to be confused with the Red Rectangle!
https://en.wikipedia.org/wiki/Red_Rectangle_Nebula

John

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 ! Hmm, I wonder if that would be more or less explainable than a Red Hexagon Nebula...

[neufer]

Red Triangle Nebula

---

Not to be confused with the Red Rectangle!
https://en.wikipedia.org/wiki/Red_Rectangle_Nebula

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 !

Red Triangle Nebula

[johnnydeep]

Red Triangle Nebula

---

Not to be confused with the Red Rectangle!
https://en.wikipedia.org/wiki/Red_Rectangle_Nebula

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 !

Red Triangle Nebula

I'll give that a B+ for effort.

[daddyo]

The cones seem to have maybe 4 periodic events/episodes to them

[VictorBorun]

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…

[Chris Peterson]

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.

[bungi]

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.

[Chris Peterson]

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.

[VictorBorun]

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

[Chris Peterson]

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.

[neufer]

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.