APOD: Simeis 147: Supernova Remnant (2012 Oct 09)

[neufer]

Spectacular image of what is surely a very faint supernova remnant! As well as Ha,
it also contains a lot of OIII emission and there are very few images that include exposures in this waveband.

OIII emission is generally the result of ultraviolet irradiation from a white dwarf CS.

You're wrong when you say that OIII is only the result of the effects of a white dwarf.

Did I say that

[BMAONE23]

Our closest neighbor is 4.2LY away. If you use this as an average density for our neighborhood then a Bubble that is 150LY diameter would encompass enopugh space to affect over 6000 stars.

[Anthony Barreiro]

Never ceases to amaze me, we all loosely throw out numbers like "150 light years across"..... but I wonder if we really get how enormously big that is compared to little old us.

Personally, I have no problem at all visualizing 150 light years. These are the sort of units I work with all the time, and consequently they seem very natural to me. I don't think that people have any inherent difficulty dealing with scales outside our daily experience, it's just a question of familiarity.

A big part of my interest in skywatching and astronomy comes from the sense of wonder and awe I experience contemplating vast spaces and cosmic timelines, and trying to to relate them to what I see through the eyepiece of a small telescope. Speaking humbly and only for myself, I hope I never get to the point where I have no problem at all visualizing 150 light years. It would take some of the fun out of it for me and I might need to find a new hobby.

[Ann]

I once built a very simple model of the inner solar system, using a round table cloth with a diameter of 2 meters as the Sun, and putting Mars, which I unfortunately had to make too big (0.02 meters, the same as the Earth) at a distance of 300 meters. When I had placed pea-sized Mercury, 0.02 meter Venus, 0.02 meter Earth (with pea-sized Moon) and Mars at the proper distances from the table-cloth Sun, I was struck by the unbelievable tininess of the planets and the incredible distances between them. The planets were "swallowed by the darkness" as it were. Our solar system seemed so empty to me, even though it is really quite crowded compared with the average density of our part of the galaxy. I tried to "blow my model up" to the real size of the inner solar system, and realized that I couldn't picture it in my mind at all.

For all of that, I can certainly picture a model of nearby space with a diameter of 150 light-years. I would put the Sun in the middle (simply because we ourselves are in the middle of such a sphere), and Alpha Centauri at four light-years away from us. I most certainly can't picture the actual distance of four light-years, but I can easily picture that a star 150 light-years away from us is 37.5 times as far away from us as Alpha Centauri. I could make a drawing of it and picture it easily.

The actual distance itself is unimaginable to me, but the "relative distance" is easy to picture. I think it has to be that way for beings whose average size as adults is on the order of about two meters.

Ann

[Chris Peterson]

A big part of my interest in skywatching and astronomy comes from the sense of wonder and awe I experience contemplating vast spaces and cosmic timelines, and trying to to relate them to what I see through the eyepiece of a small telescope. Speaking humbly and only for myself, I hope I never get to the point where I have no problem at all visualizing 150 light years. It would take some of the fun out of it for me and I might need to find a new hobby.

I find that the deeper my understanding of anything, the more I appreciate it, and the greater my sense of wonder. For me, not fully understanding something diminishes its wonder.

[neufer]

For me, not fully understanding something diminishes its wonder.

Doesn't science itself require that we don't fully understanding something

[tetrodehead]

Great picture!
In the max definition picture, near the bottom right corner at 4 o'clock from the nebula, is a ray starting near a blue star and running to the picture edge. Is the ray cosmic or a 'scratch'?

[Guest]

The explanation of the distance of Simeis 147 is faulty. The supernova remnant is 40,000 light years away. This does not mean that the light from that supernova remnant first reached earth 40,000 years ago. Rather, the light we now see from that supernova remnant left 40,000 years ago.

[Chris Peterson]

The explanation of the distance of Simeis 147 is faulty. The supernova remnant is 40,000 light years away. This does not mean that the light from that supernova remnant first reached earth 40,000 years ago. Rather, the light we now see from that supernova remnant left 40,000 years ago.

The caption is correct. The remnant is 3000 ly away. The light from the supernova reached the Earth 40,000 years ago, so we are now seeing a 40,000 year old remnant. The actual distance to the object is irrelevant.

[neufer]

The explanation of the distance of Simeis 147 is faulty. The supernova remnant is 40,000 light years away. This does not mean that the light from that supernova remnant first reached earth 40,000 years ago. Rather, the light we now see from that supernova remnant left 40,000 years ago.

There seems to be some uncertainty about when the light from the supernova remnant first reached earth but there is little doubt about the distance. (And if it were 40,000 light years away it would be 1800 light years wide )

Simeis 147 (also known as Sharpless 2-240 and the Spaghetti Nebula) is a supernova remnant in the constellations of Taurus and Auriga.

The nebulous area is fairly large, with an apparent size covering around 3 degrees, and is approximately 3000(±350) light years away, and covers an area of around 41.9 parsecs (137 ly(±25)), and is approximately 40 000 years old.>>

Simeis 147 by Davide De Martin
by Tammy Plotner, Universe Today, June 16, 2008

<<If you think we’re looking straight down the maul of the “Doomsday Machine”, you’d be pretty much correct. While the fictionalized Star Trek account had the planet killer slowly destroying a distant solar system, this particular “star eater” is very real and still exists along the Auriga-Taurus border…

Named Simeis 147, this ancient supernova remnant has expanded so much that it’s barely visible to larger telescopes. Why? Mostly because the diameter of the nebula is about 3-1/2 degrees, or about 7 times the size of the Moon – and the fact it’s one of the faintest objects in the night sky. Like many nebulous “sky scraps”, it is simply too large to be seen in its entirety – or beauty – except through the magic of astrophotograhy.

In this week’s image by Davide De Martin, we take an up close and personal look at Simeis 147. The intricate filaments of this faint supernova remnant spans over 160 light years of interstellar space and is around 3900 light years away. With an apparent age of about 100,000 years, this awesome explosion occurred around the time of Peking Man, and like our distant ancestor left more than one artifact behind. In this case, the expanding remnant is not all. Deep within the folds and rifts lay a spinning neutron star. This pulsar is all that’s left of the original star’s core.

Unlike many things unexplored, more study was indicated and newer estimated gauge Semeis 147′s age at about 30,000 years. The pulsar itself has recently been detected and has been cataloged as PSR J0538+2817. Imagine something that rotates completely on its axis seven times per second! And think about what happened… The outer layers of this exploding star initially carried outward at speeds of 10,000-20,000 km/s–a tremendous amount of energy released in a blast wave.

Supernovae are divided into classes based upon the appearance of their spectra: hydrogen lines are prominent in Type II supernovae; while hydrogen lines are absent in Type Ia supernovae. Put simply, this means the progenitor stars either had hydrogen in their outer envelopes or did not have hydrogen in their outer envelopes. Type II supernovae are the territory of massive stars while Type Ia supernovae more than likely originated with white dwarf binary star systems – a place where the accreting white dwarf is driven above the Chandrasekhar Mass Limit, collapses and explodes.

So how often do events like the Simeis 147 type happen? According to Rudolph Minkowski; “As regards the supernovae frequency, there are two types of supernovae. The Supernovae I seem to occur about every 400 or 500 years per galaxy and the Supernovae II about every 50 years per galaxy, with considerable leeway. But, the Supernovae II are certainly much more frequent than Supernova I.” In recent studies done the 610.5 MHz Contour Maps of the Supernova Simeis 147, by Dickel and McKinley, the integrated flux densities show that the radiation is probably non-thermal and incredibly old.

As old as the Star Trek “Doomsday Machine”? Its origins were also unknown and it produced mass destruction. Maybe Simeis 147 isn’t quite the same as the neutronium hulled, antiproton beam firing planet killer of Gene Roddenberry’s fictionalized story… But it is definitely as intriguing to the imagination!>>