APOD: Veil Nebula: Wisps of an Exploded Star (2021 Apr 05)

[APOD Robot]

Veil Nebula: Wisps of an Exploded Star

Explanation: Wisps like this are all that remain visible of a Milky Way star. About 7,000 years ago that star exploded in a supernova leaving the Veil Nebula. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history. Today, the resulting supernova remnant, also known as the Cygnus Loop, has faded and is now visible only through a small telescope directed toward the constellation of the Swan (Cygnus). The remaining Veil Nebula is physically huge, however, and even though it lies about 1,400 light-years distant, it covers over five times the size of the full Moon. The featured picture is a Hubble Space Telescope mosaic of six images together covering a span of only about two light years, a small part of the expansive supernova remnant. In images of the complete Veil Nebula, even studious readers might not be able to identify the featured filaments.

<< Previous APOD

This Day in APOD

Next APOD >>

[Ifikratis]

Incredible image.

If not a camera artifact, at the upper part of the image (more easily seen on the middle left) there are parallel blue lines which seem to be interstellar magnetic field lines.

[SpaceCadet]

How large is the nebula in total? What does 5 times the size of the full moon at 1400 light year's distance mean? Thanks

[MarkBour]

In images of the complete Veil Nebula, even studious readers might not be able to identify the featured filaments.

Okay, that sounds like a veiled challenge to locate today's APOD in the APOD from 2019-10-31 (https://apod.nasa.gov/apod/ap191031.html).

And it does seem rather challenging. The lighting may be different, and by
a crudely estimated 1/35 field of view, the scales are vastly different.

Here's my guess, the tiny red rectangle in the image at the right.

But my confidence is low.

How large is the nebula in total? What does 5 times the size of the full moon at 1400 light year's distance mean? Thanks

The image at the right shows the entire veil nebula. Astronomers had estimated that the wispy structure lies about 1400 light years away. Then, using geometry, since it covers about 2-3 degrees in angular diameter (5 times the angular diameter of the Moon), then it would have to be about 70 light years in diameter. My numbers are really approximate.

In fact, all of the above turned out to be very approximate. Wikipedia (at https://en.wikipedia.org/wiki/Veil_Nebula) notes that recent astrometric measurements have placed the nebula at a distance of 2400 light years, not just 1400 light years. If it is farther away, then it must actually be bigger. Instead of 70 light years in diameter, it must be 70 * (2400/1400) = 120 light years in diameter. (Again, I'm being very approximate. Wikipedia lists it as 130 light years.)

. . . But you could ask again tomorrow!
A fascinating fact at the end of the Wikipedia article:

The Veil Nebula is expanding at a velocity of about 1.5 million kilometers per hour. Using images taken by the Hubble Space Telescope between 1997 and 2015, the expansion of the Veil Nebula has been directly observed.

[SpaceCadet]

@MarkBour - thanks for the info. That last bit is especially great bc I have always wondered if astronomers could actually see and watch the expansion of the galaxies they study considering their size and speed.

[heehaw]

Please don't miss today's ESPOD which is extremely interesting! Fabulous! https://epod.usra.edu/blog/

[orin stepanek]

The way APOD presents the veil today is very beautiful

[neufer]

---

---

[Chris Peterson]

Incredible image.

If not a camera artifact, at the upper part of the image (more easily seen on the middle left) there are parallel blue lines which seem to be interstellar magnetic field lines.

There is no reason to think that this region contains magnetic fields strong enough to direct the flow of material significantly. All of the structure is generated by shock fronts.

[Chris Peterson]

@MarkBour - thanks for the info. That last bit is especially great bc I have always wondered if astronomers could actually see and watch the expansion of the galaxies they study considering their size and speed.

We have never observed motion in galaxies (and galaxies don't expand, in any case). We can directly see the motion of some fairly nearby stars, and of gas in a few planetary nebulas and supernova remnants (like this one). Everything else is too far away for us to see any change over the amount of time we've had to observe so far.

[bystander]

ESA: Return to the Veil Nebula

[Cousin Ricky]

In images of the complete Veil Nebula, even studious readers might not be able to identify the featured filaments.

I’m guessing the Witch’s Broom.

[Cousin Ricky]

In images of the complete Veil Nebula, even studious readers might not be able to identify the featured filaments.

Okay, that sounds like a veiled challenge to locate today's APOD in the APOD from 2019-10-31 (https://apod.nasa.gov/apod/ap191031.html).

Capture.png

And it does seem rather challenging. The lighting may be different, and by
a crudely estimated 1/35 field of view, the scales are vastly different.

Here's my guess, the tiny red rectangle in the image at the right.

But my confidence is low.

I think you nailed it.

[eegriff]

Veil Nebula fragment located. Watch the video. https://www.youtube.com/watch?v=hlx-6FVyT8o

[VictorBorun]

In images of the complete Veil Nebula, even studious readers might not be able to identify the featured filaments.

Okay, that sounds like a veiled challenge to locate today's APOD in the APOD from 2019-10-31 (https://apod.nasa.gov/apod/ap191031.html).

Capture.png

And it does seem rather challenging. The lighting may be different, and by
a crudely estimated 1/35 field of view, the scales are vastly different.
Here's my guess, the tiny red rectangle in the image at the right.
But my confidence is low.

[/quote]

I gave it a try and failed

[VictorBorun]

Veil Nebula fragment located. Watch the video. https://www.youtube.com/watch?v=hlx-6FVyT8o

yes!

[johnnydeep]

Veil Nebula fragment located. Watch the video. https://www.youtube.com/watch?v=hlx-6FVyT8o

yes!

I always seem to need visual aids:

Veil Nebula Fragment - Where Does It Fit?

[johnnydeep]

Veil Nebula: Wisps of an Exploded Star

Explanation: Wisps like this are all that remain visible of a Milky Way star. About 7,000 years ago that star exploded in a supernova leaving the Veil Nebula. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history. Today, the resulting supernova remnant, also known as the Cygnus Loop, has faded and is now visible only through a small telescope directed toward the constellation of the Swan (Cygnus). The remaining Veil Nebula is physically huge, however, and even though it lies about 1,400 light-years distant, it covers over five times the size of the full Moon. The featured picture is a Hubble Space Telescope mosaic of six images together covering a span of only about two light years, a small part of the expansive supernova remnant. In images of the complete Veil Nebula, even studious readers might not be able to identify the featured filaments.

Does the progenitor star (20 times the mass of the Sun per WikiPedia) still exists, and if so, has it been located? Is it a white dwarf or a neutron star?

[eegriff]

Veil Nebula fragment located. Watch the video. (My earlier post had the wrong date in the video. It's been fixed.) https://youtu.be/1CRvDDOR2eU

[neufer]

Does the progenitor star (20 times the mass of the Sun per WikiPedia) still exists, and if so, has it been located? Is it a white dwarf or a neutron star?

?

---

<<Most stars that produce supernovae leave behind compact stellar remnants- a neutron star or black hole, typically depending on the mass of the original star. Various techniques based on the features of the supernova remnant estimate the Cygnus Loop progenitor star's mass at 12 to 15 Solar masses, a value that puts the expected remnant firmly within neutron star boundaries. However, despite many searches, no compact stellar remnant had been confidently identified since the identification of the supernova remnant.

A noted anomaly is that in X-rays, the nebula appears perfectly spherical aside from a "blowout region" to the south. Searches for a compact stellar remnant have been largely concentrated here, as the hole may have been caused by the violent ejection of a neutron star. A detailed 2012 study of the blowout region identified a possible pulsar wind nebula, as well as a point-like source within it. Although at almost exactly the same position as a known Seyfert galaxy, the slight offset combined with a lack of a radio counterpart makes the point-like source probably unrelated to the galaxy. Whether or not the feature is a pulsar wind nebula or not, and if so whether or not it is related to the Cygnus Loop, is still unknown for certain. If it is indeed the compact stellar remnant of the supernova, the neutron star would have to have been ejected from the center of the nebula at a speed of roughly 1,850 km/s, depending on the precise age and distance of the remnant.>>

[johnnydeep]

Does the progenitor star (20 times the mass of the Sun per WikiPedia) still exists, and if so, has it been located? Is it a white dwarf or a neutron star?

?

---

<<Most stars that produce supernovae leave behind compact stellar remnants- a neutron star or black hole, typically depending on the mass of the original star. Various techniques based on the features of the supernova remnant estimate the Cygnus Loop progenitor star's mass at 12 to 15 Solar masses, a value that puts the expected remnant firmly within neutron star boundaries. However, despite many searches, no compact stellar remnant had been confidently identified since the identification of the supernova remnant.

A noted anomaly is that in X-rays, the nebula appears perfectly spherical aside from a "blowout region" to the south. Searches for a compact stellar remnant have been largely concentrated here, as the hole may have been caused by the violent ejection of a neutron star. A detailed 2012 study of the blowout region identified a possible pulsar wind nebula, as well as a point-like source within it. Although at almost exactly the same position as a known Seyfert galaxy, the slight offset combined with a lack of a radio counterpart makes the point-like source probably unrelated to the galaxy. Whether or not the feature is a pulsar wind nebula or not, and if so whether or not it is related to the Cygnus Loop, is still unknown for certain. If it is indeed the compact stellar remnant of the supernova, the neutron star would have to have been ejected from the center of the nebula at a speed of roughly 1,850 km/s, depending on the precise age and distance of the remnant.>>

Thanks, neufer! Very interesting.

[MarkBour]

Veil Nebula fragment located. Watch the video. https://www.youtube.com/watch?v=hlx-6FVyT8o

Nice!