Pencil Nebula: Knot D pictures (APOD 2009 January 8)

[neufer]

http://apod.nasa.gov/apod/ap090108.html

http://violet.pha.jhu.edu/~wpb/hstvela/hstvela.html

<<The Vela Knot D region is interesting, and my colleagues Ravi Sankrit, John Raymond and I have recently published a paper on the ultraviolet emissions from this region (links to a pdf file). The X-ray Knot D is bounded by a beautiful "fan" of optical filaments know commonly as
the Pencil Nebula (NGC 2736).



Briefly, when first discovered the Knot D region (as well as the other protrusions seen in X-rays) was thought to represent a place where "ejecta" (chunks of the precursor star) were being shot out at high velocity from the explosion site. However, even with extensive observations of the region, it has been difficult to confirm (or refute!) this claim. The ultraviolet and optical observations are consistent with the region being a "breakout" from the main shell of the SNR. That is, a weaker, lower density portion of the shell may have allowed the main shock wave to "run ahead" in this region, and the shock wave is now encountering a denser region again, causing the X-ray and optical/UV emission we see. We do not find evidence for peculiar abundances or physical conditions that would indicate stellar ejecta are involved in creating this structure Future observations, including some with the Chandra X-ray Observatory, are being pursued to reconcile which of these models might be correct.

One final surprise discovered fairly recently is that yet another supernova remnant is present along this line of sight! When the Rosat X-ray data shown above were processed in a way that showed only the higher energy X-rays, a separate, smaller diameter shell popped out:

Caption: These two images show low (left) and high (right) energy X-ray images of the same piece of sky (from Aschenbach, B. 1998, Nature, 396, 141). In the right panel, a separate supernova remnant, about 2 degrees across, is revealed.

The distance to this new supernova remnant (known formally as RX J0852.0-4622, but known affectionately as "Vela Jr.") is a matter of hot debate. It could be a background object, similar to the Puppis A SNR mentioned above. A more tantalizing possibility, though, is that it is physically associated with the Vela SNR, and represents an even younger supernova from within the same generation of stars! The discovery image above even raises the possibility that the Vela D/Pencil Nebula region could be associated with THIS OBJECT instead of the Vela SNR itself.

It's amazing sometimes how surprises pop out of new observations, and how difficult is can be to discern the true situation!>>

[apodman]

So be good for goodness sake.

[neufer]

So be good for goodness sake.

"I just got back from a lovely trip along the Milky Way"
- _Santa Claus Is Coming To Town_ by Coots & Gillespie (1934)

http://www.wikisky.org/?object=Vela+Sup ... ource=RASS
http://www.wikisky.org/?object=Vela+Sup ... ource=IRAS
http://www.skyfactory.org/vela/vela.htm

[neufer]

5 Somali pirates drown with share of ransom money
after releasing Saudi [VELA] SUPERtanker
By MOHAMED OLAD HASSAN Associated Press Writer
MOGADISHU, Somalia January 10, 2009 (AP)
http://www.abcnews.go.com/Business/wireStory?id=6617076

<<Five of the pirates who hijacked a Saudi supertanker drowned with
their share of a $3 million ransom, a relative said Saturday, the day
after the bundle of cash was apparently dropped by parachute onto the
deck of the ship. The Sirius Star and its 25 crew sailed safely away
Friday at the end of a two-month standoff in the Gulf of Aden, where
pirates attacked over 100 ships last year. Hundreds more kidnapped
sailors remain in the hands of pirates.

The drowned pirates' boat overturned in rough seas, and family members
were still looking for four missing bodies, said Daud Nure, another
pirate who knew the men involved.

Somalia's lawless coastline borders one of the world's busiest
shipping lanes, which links the Mediterranean Sea and the Red Sea to
the Indian Ocean. Attacks have continued despite the patrols by
warships from France, Germany, Britain, America, India and China.

The naval coalition has been closely monitoring both the Sirius Star
and the Faina, a Ukrainian ship loaded with military tanks that has
been held since September. The seizure of the Sirius Star on Nov. 15
prompted fears that the pirates might release some of the cargo of
crude oil into the ocean, causing an environmental disaster as a way
of pressuring negotiators. At the time, the oil was valued at $100
million.

Abukar Haji, uncle of one of the dead pirates, blamed the naval
surveillance for the accident that killed his pirate nephew Saturday.
"The boat the pirates were traveling in capsized because it was
running at high speed because the pirates were afraid of an attack
from the warships patrolling around," he said. "There has been human
and monetary loss but what makes us feel sad is that we don't still
have the dead bodies of our relatives. Four are still missing and one
washed up on the shore."

Pirate Daud Nure said three of the eight passengers had managed to
swim to shore after the boat overturned in rough seas. He was not part
of the pirate operation but knew those involved. "Here in Haradhere
the news is grim, relatives are looking for their dead," he said.

The tanker had left Somali territorial waters and was on its way home
Saturday, said Saudi Arabian oil minister Ali Naimi. A Saudi Oil
Ministry official said the ship was headed for Dammam, on the
country's Gulf coast, but gave no estimated time of arrival. The
official spoke on condition of anonymity because he was not authorized
to speak to the press.

The U.S. Navy, which announced this week it will head a new anti-
piracy task force, released photos Friday showing a parachute,
carrying what was described as "an apparent payment," floating down
toward the tanker.

The Liberian-flagged ship is owned by Vela International Marine Ltd.,
a subsidiary of Saudi oil company Aramco. Neither commented on the
reported ransom drop. "All the crew members are safe and I am glad to
say that they are all in good health and high spirits," said a
statement by Saleh K'aki, president and CEO of Vela. "Throughout this
ordeal, our sole objective was the safe and timely release of the
crew. That has been achieved today."
.
But over a dozen ships and around 300 crew members are still being
held. The capture of the Sirius Star has already demonstrated the
pirates' ability to strike high value targets hundreds of miles
offshore.
.
On the same day the Saudi ship was freed, pirates released a captured
Iranian-chartered cargo ship, Iran's state television reported
Saturday. The ship Delight was carrying 36 tons of wheat when it was
attacked in the Gulf of Aden Nov. 18 and seized by pirates. All 25
crew are in good health and the vessel is sailing toward Iran, the TV
report said. It did not say if a ransom was paid.>>

[sunfield41]

Who witnessed the supernova Vela 11,000 years ago. and how do we know?

[neufer]

Who witnessed the supernova Vela 11,000 years ago?

Jason and the Argonauts.

<<Argo Navis was a large constellation in the southern sky that has since been divided into three separate constellations. It represented the Argo, the ship used by Jason and the Argonauts in Greek mythology. The abbreviation was "Arg" and the genitive was "Argūs Navis".
.
Argo Navis is the only one of the 48 constellations listed by the 1st century astronomer Ptolemy that is no longer officially recognised as a constellation. It was unwieldy due to its enormous size - were it still considered a single constellation, it would be the largest of all. In 1752, the French astronomer Nicolas Louis de Lacaille subdivided it into Carina (the keel of the ship), Puppis (the poop deck), and Vela (the sails). When Argo Navis was split, its Bayer designations were also split. Carina has the α, β and ε, Vela has γ and δ, Puppis has ζ, and so on.
.
The constellation Pyxis (the mariner's compass) occupies an area which in antiquity was considered part of Argo's mast. However, Pyxis is not now considered part of Argo Navis, and its Bayer designations are separate from those of Carina, Puppis and Vela.>>

-----------------------------------------
. Antony and Cleopatra > Act II, scene II
.
DOMITIUS ENOBARBUS: I will tell you.
. The barge she sat in, like a burnish'd throne,
. Burn'd on the water: the poop was beaten gold;
. Purple the sails, and so perfumed that
. The winds were love-sick with them; the oars were silver,
. Which to the tune of flutes kept stroke, and made
. The water which they beat to follow faster,
. As amorous of their strokes. For her own person,
. It beggar'd all description: she did lie
. In her pavilion--cloth-of-gold of tissue--
. O'er-picturing that Venus where we see
. The fancy outwork nature: on each side her
. Stood pretty dimpled boys, like smiling Cupids,
. With divers-colour'd fans, whose wind did seem
. To glow the delicate cheeks which they did cool,
. And what they undid did.
-----------------------------------------

[Chris Peterson]

Who witnessed the supernova Vela 11,000 years ago. and how do we know?

Maybe nobody, although there were certainly a fair number of modern humans around at the time, and I expect they spent time studying the night sky.

But I think the phrase "seen to explode about 11,000 years ago" was chosen to make it clear when the supernova happened in our time reference, in order to avoid the confusion associated when time and distance are considered together (although in this case, the distance is close and the time is long, so the distance doesn't much change things, no matter how you interpret time).

[bystander]

Who witnessed the supernova Vela 11,000 years ago?

Jason and the Argonauts.

I really don't think Jason was around 11,000 years ago. The timing just doesn't seem right.

[sunfield41]

It was interesting to hear from such imaginative people. I'm very glad I bumbled my way into this forum.

Thank you! Made my day.

Sunfield41

[Chris Peterson]

I really don't think Jason was around 11,000 years ago. The timing just doesn't seem right.

Indeed. The myth is set roughly around the time of the Trojan War, say 3500 years ago, give or take. Nowhere near 11000.

[neufer]

I really don't think Jason was around 11,000 years ago. The timing just doesn't seem right.

Indeed. The myth is set roughly around the time of the Trojan War, say 3500 years ago, give or take. Nowhere near 11000.

So it's just a myth that Jason lived
"roughly around the time of the Trojan War, say 3500 years ago, give or take."

I rest my case!

[Chris Peterson]

I really don't think Jason was around 11,000 years ago. The timing just doesn't seem right.

Indeed. The myth is set roughly around the time of the Trojan War, say 3500 years ago, give or take. Nowhere near 11000.

So it's just a myth that Jason lived
"roughly around the time of the Trojan War, say 3500 years ago, give or take."

I rest my case! :|

What case? The characters around Jason overlap characters that are associated with the literary Trojan War, which itself is probably based on events that happened somewhere around 1200 BCE. Mythical and fictional characters aren't generally timeless, but are set into some historical context.

On the other hand, 11000 years ago humans were just discovering civilization, settling down into stable villages. It's hard to imagine that these people (who likely had full time priest astronomers), as well as many nomadic peoples, wouldn't have seen a supernova that occurred so very close.

[neufer]

<<Potentially sites of ongoing star formation, these cosmic tadpole shapes are about 10 light-years long.>>

The myth is set roughly around the time of the Trojan War, say 3500 years ago, give or take. Nowhere near 11000.

So it's just a myth that Jason lived
"roughly around the time of the Trojan War, say 3500 years ago, give or take."

I rest my case!

What case? The characters around Jason overlap characters that are associated with the literary Trojan War, which itself is probably based on events that happened somewhere around 1200 BCE. Mythical and fictional characters aren't generally timeless, but are set into some historical context.

Mythical and fictional characters are essentially timeless.

On the other hand, 11000 years ago humans were just discovering civilization, settling down into stable villages. It's hard to imagine that these people (who likely had full time priest astronomers), as well as many nomadic peoples, wouldn't have seen a supernova that occurred so very close.

And these shaman priests of Colchis (modern day Abkhazia) would confront and eventually lose out
to modern western civilization which then (unknowingly) hung the golden fleece on Jason's sail.

ARIEL : I boarded the king's ship; now on the beak,
. Now in the waist, the deck, in every cabin,
. I flamed amazement: sometime I'ld divide,
. And burn in many places; on the topmast,
. The yards and bowsprit, would I flame distinctly,
. Then meet and join.

http://antwrp.gsfc.nasa.gov/apod/ap000819.html
http://antwrp.gsfc.nasa.gov/apod/ap020217.html
--------------------------------------------------------------
"God, Kinch, if you and I could only work together we might do something for the island.
Hellenise it." - James Joyce » Ulysses » Episode 1 - Telemachus

[bystander]

Mythical and fictional characters are essentially timeless.

Some mythical and fictional characters are essentially timeless. Others are closely associated with historical periods (eg King Arthur). Jason and the Argonauts (Heracles, Peleus and Telamon, Castor and Pollux, et al) were contemporaneous with the events of the Illiad and Odyssey (ie the Trojan War), generally agreed to be 13th century BCE.

BTW, this was about the same time frame as that other great legend Moses and the Exodus from Egypt.

[neufer]

Mythical and fictional characters are essentially timeless.

Some mythical and fictional characters are essentially timeless. Others are closely associated with historical periods (eg King Arthur). Jason and the Argonauts (Heracles, Peleus and Telamon, Castor and Pollux, et al) were contemporaneous with the events of the Illiad and Odyssey (ie the Trojan War), generally agreed to be 13th century BCE.

Jason and the Argonauts (1963)
..............................................
Phineas: Go ahead, Zeus. Throw down a thunderbolt,
. let the earth swallow me up. I defy you!

[Loud crash of thunder]

Phineas: You can growl away all you like, Zeus. I mean what I say.

[bystander]

Jason and the Argonauts (1963)
..............................................
Phineas: Go ahead, Zeus. Throw down a thunderbolt,
. let the earth swallow me up. I defy you!

[Loud crash of thunder]

Phineas: You can growl away all you like, Zeus. I mean what I say.

I would never presume to challenge the gods (I don't understand gods). I yield.