Starship Asterisk*

Meekmoe wrote:Why the gap in the data?

https://en.wikipedia.org/wiki/Circinus wrote:
<<Circinus is a small faint constellation in the southern sky,
first defined in 1756 by French astronomer Nicolas Louis de Lacaille.

Its name is Latin for compass, referring to
the drafting tool used for drawing circles.>>

Meekmoe wrote:Why the gap in the data?

NGC3314 wrote:

Meekmoe wrote:Why the gap in the data?

Chandra's much-used ACIS instrument has 8 CCD detectors of two different kinds in adjacent arrays, one 2x2 square and one 4x1 optimized for dispersed spectra; each CCD covers a region about 8 arc minutes square. The break in the light echo in the released image composite is caused by the gap between two of these when the main X-ray target is put at the best compromise aim point. (This is mentioned briefly in the news release here). If the observers didn't know they would be looking for the echo at the time of observations planning this is what would have showed up (if they had known and waited better coverage, they could have specified offset telescope pointing or a dither pattern of continuous motion during the observations).

Mulsar wrote:I always assumed that a super nova was one of the most destructive forces in the universe. So the statement that the binary partner to the neutron star survived the explosion is a little confusing at least to me. I think we have seen how the force of super nova explosions can be directed in unusual ways. Is this what happened in this system with the force of the super nova being directed away from the binary partner leaving it mostly intact?

puhbrox wrote:Wow that is simply beautiful. What exactly did this look like to the Ancient Greeks? Was it something EXTREMELY bright in the plane of the milky way? On the same note, did we just stumble across these ripples and strange cloud formations, or do a lot of neutron stars look like this and we are finally only able to see this strange array now thanks to Chandra?

Meekmoe wrote:Why the gap in the data?

Meekmoe wrote: I remember learning that they wanted to put more of the nested mirrors but couldn't because of weight restrictions. Still an amazing instrument!

Chris Peterson wrote:

puhbrox wrote:Wow that is simply beautiful. What exactly did this look like to the Ancient Greeks? Was it something EXTREMELY bright in the plane of the milky way? On the same note, did we just stumble across these ripples and strange cloud formations, or do a lot of neutron stars look like this and we are finally only able to see this strange array now thanks to Chandra?

I'm skeptical that this supernova appeared to the ancient Greeks (in ~500 BCE as suggested by the graphic). The paper dates the formation of the x-ray system to as much as 4600 years ago, which means 2500 BCE. The Greeks were still isolated tribes. This was the period of the Egyptian Old Kingdom, of Mesopotamia and the rise of Ur, of the Indus Valley civilization.

A supernova like this would appear as a very bright star in the sky, likely visible in the day for a few weeks or months. Probably very scary to cultures that tended to look on any unexpected events in the sky as harbingers of doom.

Chris Peterson wrote:

puhbrox wrote:
What exactly did this look like to the Ancient Greeks? Was it something EXTREMELY bright in the plane of the milky way? On the same note, did we just stumble across these ripples and strange cloud formations, or do a lot of neutron stars look like this and we are finally only able to see this strange array now thanks to Chandra?

I'm skeptical that this supernova appeared to the ancient Greeks (in ~500 BCE as suggested by the graphic). The paper dates the formation of the x-ray system to as much as 4600 years ago, which means 2500 BCE. The Greeks were still isolated tribes. This was the period of the Egyptian Old Kingdom, of Mesopotamia and the rise of Ur, of the Indus Valley civilization.

A supernova like this would appear as a very bright star in the sky, likely visible in the day for a few weeks or months. Probably very scary to cultures that tended to look on any unexpected events in the sky as harbingers of doom.

• But the first recorded supernova was by Chinese astronomers 1830 years ago
  [also in Circinus but much closer: 9,100 ly vs. 30,700 ly for Circinus X-1
  (; i.e., apparent magnitude -1.4 vs. -4)]:

https://en.wikipedia.org/wiki/SN_185 wrote:

[b][size=150][color=#0000FF]SN 185 (aka RCW 86)[/color][/size][/b]

---

<<SN 185 (aka RCW 86) was a supernova which appeared in the year AD 185, near the direction of Alpha Centauri, between the constellations Circinus and Centaurus, centered at RA 14h 43m Dec −62° 30′, in Circinus. This "guest star" was observed by Chinese astronomers in the Book of Later Han, and might have been recorded in Roman literature. It remained visible in the night sky for eight months. This is believed to have been the first supernova recorded.

The gaseous shell RCW 86 is probably the supernova remnant of this event and has a relatively large angular size of roughly 45 arc minutes (larger than the apparent size of the full moon, which varies from 29 to 34 arc minutes). The distance to RCW 86 is estimated to be 2,800 parsecs (9,100 light-years). Recent X-ray studies show a good match for the expected age.

Differing modern interpretations of the Chinese records of the guest star have led to quite different suggestions for the astronomical mechanism behind the event, from a core-collapse supernova to a distant, slow-moving comet – with correspondingly wide-ranging estimates of its apparent visual magnitude (−8 to +4). The recent Chandra results suggest that it was most likely a Type Ia supernova (a type with consistent absolute magnitude), similar therefore to Tycho's star (which had apparent magnitude −4 at a similar distance).>>

Guest wrote:"In the Constellation of Cygnus, there lurks...a mysterious invisible force."

This is not Cygnus X-1...

geckzilla wrote:

Guest wrote:
"In the Constellation of Cygnus, there lurks...a mysterious invisible force."

This is not Cygnus X-1...

Where do you see that at?

• http://tinyurl.com/oxo57ot