Starship Asterisk*

Simeis 147: Supernova Remnant

Explanation: It's easy to get lost following the intricate looping filaments in this detailed image of supernova remnant Simeis 147. Also cataloged as Sharpless 2-240 it goes by the popular nickname, the Spaghetti Nebula. Seen toward the boundary of the constellations Taurus and Auriga, it covers nearly 3 degrees or 6 full moons on the sky. That's about 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years. This composite includes image data taken through narrow-band filters where reddish emission from ionized hydrogen atoms and doubly ionized oxygen atoms in faint blue-green hues trace the shocked, glowing gas. The supernova remnant has an estimated age of about 40,000 years, meaning light from the massive stellar explosion first reached Earth 40,000 years ago. But the expanding remnant is not the only aftermath. The cosmic catastrophe also left behind a spinning neutron star or pulsar, all that remains of the original star's core.

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Strange image

I can understand the Spaghetti Nebula; but to me it's the Pig Nebula!

orin stepanek wrote: ↑Thu Nov 21, 2019 1:06 pm
I can understand the Spaghetti Nebula; but tm it's the Pig Nebula!

"I have seen God face-to-face,
and I am still alive"

neufer wrote: ↑Thu Nov 21, 2019 2:06 pm

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orin stepanek wrote: ↑Thu Nov 21, 2019 1:06 pm
I can understand the Spaghetti Nebula; but tm it's the Pig Nebula!

"I have seen God face-to-face,
and I am still alive"

Ann

If the estimated age is 40,000 years and it's 3,000 light years away, then the first light of the supernova to reach Earth would have been 37,000 years ago. What we see today is how it appeared 3,000 years ago.

If I'm 10 years old in New York City and I send a photograph of myself by land mail to someone in China and it takes 6 months to arrive, then, although the photo shows me as a ten year old, I'm actually 10 years and six months old.
If today's APOD appeared 40,000 years ago when seen on Earth and is judged by that measure to be 40,000 years old, then what accounts for the change in the subject's structure during the ensuing 3,000 years when what we are seeing was first generated?
I assume, as with 10 year old boys, Supernovas change with time as well.

Misha115 wrote: ↑Thu Nov 21, 2019 8:18 pm
If the estimated age is 40,000 years and it's 3,000 light years away, then the first light of the supernova to reach Earth would have been 37,000 years ago. What we see today is how it appeared 3,000 years ago.

• If the estimated age is of the observed remnant is 40,000 years
  and it's 3,000 light years away, then,
  technically, the supernova would have occurred 43,000 years ago.
  
  However, as a practical matter, it is quite appropriate
  to specify that the supernova occurred 40,000 years ago.

Misha115 wrote: ↑Thu Nov 21, 2019 8:18 pm If the estimated age is 40,000 years and it's 3,000 light years away, then the first light of the supernova to reach Earth would have been 37,000 years ago. What we see today is how it appeared 3,000 years ago.

We're seeing it at an age of 40,000 years. That means that the supernova would have been observed on Earth 40,000 years ago. The distance to the object is irrelevant.

DL MARTIN wrote: ↑Thu Nov 21, 2019 8:31 pm If today's APOD appeared 40,000 years ago when seen on Earth and is judged by that measure to be 40,000 years old, then what accounts for the change in the subject's structure during the ensuing 3,000 years when what we are seeing was first generated?

What does "accounts for" mean?

All you are asking is "what will this remnant look like in 3000 years?" You could as easily ask that for any arbitrary future time. And the answer is, we observe the current state, and based on those observations, extrapolate the future position of the material using our best available models for how gases and dust in space behave.

DL MARTIN wrote: ↑Thu Nov 21, 2019 8:31 pm
If I'm 10 years old in New York City and I send a photograph of myself by land mail to someone in China and it takes 6 months to arrive, then, although the photo shows me as a ten year old, I'm actually 10 years and six months old.

If today's APOD appeared 40,000 years ago when seen on Earth and is judged by that measure to be 40,000 years old, then what accounts for the change in the subject's structure during the ensuing 3,000 years when what we are seeing was first generated?
I assume, as with 10 year old boys, Supernovas change with time as well.

Sequence of HST SN 1987A images from 1994 to 2009, showing the collision of the expanding remnant with a ring of material ejected by the progenitor 20,000 years before the supernova,

It is important to know the absolute dimensions of these photos using the estimated distance of 168,000 light-years.

It is NOT important to know the absolute time of these photos using the estimated distance of 168,000 light-years.

Is there any way to estimate the mass of the original star relative to our Sun? I'm just musing about whether our star might produce something that beautiful sometime in the future.

dlw wrote: ↑Thu Nov 21, 2019 11:06 pm Is there any way to estimate the mass of the original star relative to our Sun? I'm just musing about whether our star might produce something that beautiful sometime in the future.

A star needs to be at least ten times more massive than the Sun to produce a supernova. Lower mass stars like the Sun end up as white dwarfs after blowing off some of their material into a small planetary nebula.