Vela-X supernova and carbon dating?

[Andre]

What could those two things have in common?

Vela-X exploded some 11,000 years ago. How do we know that 11,000 years, was it carbon dated somehow? Because if so then the calibrated date to calendar years would have been 13,000 years. Could that have caused a significant increase in cosmogenic radioactivity that would have doubled the radio carbon production ( 14N + n -> 14C + 1H ) in the atmosphere at 13,000 years.

You can see that unexplainable radiocarbon spike (delta 14C detrented) here - third plot:

http://www.ncdc.noaa.gov/paleo/pubs/hughen2000/fig4.jpg

 

[Nereid]

The ages of 'recent' SNR are determined, AFAIK, primarily by astrophysics (no terrestrial inputs required).

 

[Andre]

Thanks Nereid. However, cross checking ideas with different branches of science seems not to be a bad idea. It can lead to unusual discoveries Anyway, that peculiar 14C spike has been explained previously with massive sea ice cover during that period of the Younger Dryas (YD), this hypothetical ice cover would disturb normal CO2 exchange between atmosphere and ocean interrupting the normal fractination that depletes the atmospheric CO2 with 14C, whilst enriching oceanic CO2.

http://home.wanadoo.nl/bijkerk/delta14C.GIF

However the spike starts before the onset of the YD at 13,000 years ago and diminishes during that period as of 12,700 years ago. Even if all oceans were covered with ice, the spike would still seem to be too steep. But the reduction of delta 14C during the Younger Dryas indicates an increase of atmosphere- ocean interaction, to reach equilibrium again slowly. This would falsify the sea ice - YD claim. But nothing explains the cause of the spike. One of the very few remaining real Ice age mysteries. Since 14C is produced cosmogenically (if that's a word) it seems worthwhile to investigate possible variation in cosmogenic radioactivity.

So that's where Vela-X comes in. But the dating is wrong obviously, unless the astrophysical dating method allows for large enough error bars. Or could there have been an alternate astrological radioactivity source? Is the duration of the spike (~220-230) years of any significance?

 

[NileQueen]

http://antwrp.gsfc.nasa.gov/apod/ap960612.html
Your source says about 11,000 years ago.

The Distance to the Vela Supernova Remnant was measured by Cha, Sembach, and Danks, who reported in astro-ph/9902230 that "... The analysis of a significant sample of O and B stars in the direction of the Vela SNR has enabled a direct distance measurement of 250 +/-30 pc, with a conservative upper limit of 390 +/- 100 pc. ...". They also state the following attributes of Vela SNR at 250 +/- 30 pc:

Diameter: 32 +/- 4 pc Using angular size of 7.3 degrees (Aschenbach 1993).
Age of Remnant:
11,400 yr from Pulsar spin-down age (Reichley et al. 1970).
13,000 yr < t < 16,000 yr from Shock velocity considerations (Wallerstein & Silk 1971).
Energy of Remnant: 1 or 2 x 10^51 ergs See Jenkins & Wallerstein (1995).
Temperature Behind Blast: 4.5 x 10^6 K See Jenkins & Wallerstein (1995).
People on Earth saw the explosion about 11,000 years ago as a star of magnitude -10, as bright as a 7-day old Moon.

http://www.valdostamuseum.org/hamsmith/13Mar41.html


But if the people on Earth saw it about 11,000 years ago, and its distance is 250 +/-30 parsecs…to 490 pc upper limit….
1 parsec is 3.21 light years 1 light yr = 6 trillion miles

220 pc x 3.2 lt. yr/pc= 704 490 x 3.2 = 1568

the #years earlier the supernova occurred (from parsec figures) would be 704 to 1568 years. Add that to the 11,000 years

11,704 to 12,568 year range

For example, Supernova 1987a occurred in a "nearby" galaxy called the Large Magellanic Cloud (adjacent figure). Its light was observed on Earth in 1987, but the distance to the Large Magellanic Cloud is about 190,000 light years. Thus, we normally say that Supernova 1987a occurred in 1987, but it really happened about 190,000 years earlier; only in 1987 did the light of the explosion reach the earth! If we want to know what the Large Magellanic Cloud looks like "now", we will have to wait 190,000 years.

In comparison, the Sun is only about 8 light-minutes away. So the light we see from the Sun represents what the Sun looked like 8 minutes ago, and we must wait another 8 minutes to see what it looks like "now".

http://csep10.phys.utk.edu/guidry/violence/lightspeed.html

 

[NileQueen]

historical records...

http://www.mpa-garching.mpg.de/HIGHLIGHT/2000/highlight0005_e.html

Later supernovae, compared with Chinese historical documents spanning 4000 years. Would these also have caused disruptions to the 14C ratio?

 

[NileQueen]

Correlating supernova evidence

http://www.physics.mcgill.ca/~cliff/papers/Icecore.pdf

correlation with ice cores...

The following source also seems to indicate dating on the Vela supernova at ~11,000

The supernova explosion left a spinning pulsar at the core of the Vela region. Based on the rate at which the pulsar is slowing down, astronomers estimate that the explosion may have occurred about 11,000 years ago. Although no historical records of the blast exist, the Vela supernova would have been 250 times brighter than Venus and would have been easily visible to southern observers in broad daylight. The age of the blast, if correct, would imply that the initial explosion pushed material from the star at nearly 22 million miles per hour. As the Vela supernova remnant expands, the speed of its moving filaments, such as the Pencil Nebula, decreases. The Pencil Nebula, for example, is moving at roughly 400,000 miles per hour.

http://hubblesite.org/newscenter/newsdesk/archive/releases/2003/16/image/a

 

[NileQueen]

http://www.physics.mcgill.ca/~cliff/papers/Icecore.pdf

This first link is looking at 4 spikes of nitrates and correlating the oldest one to a Vela supernova with its light reaching Earth as early as 700 years ago.(1320 A.D.)

If the supernova occurred ~11,000 you and the distance is 220 - 490 Pc, when would it have been seen?

What is the source for the historical remark of people seeing a supernova ~11,000 ya?
Does the 1320 A.D. figure make sense with the other data?