Nova V407 Cyg – found by amateurs

Nova V407 Cyg was found at constellation Cygnus by 3 amateur Japanese astronomers
V407 Cyg lies 9,000 light-years away. The system is a so-called symbiotic binary containing a compact white dwarf and a red giant star about 500 times the size of the sun.

“The red giant is so swollen that its outermost atmosphere is just leaking away into space,” said Adam Hill at Joseph Fourier University in Grenoble, France. The phenomenon is similar to the solar wind produced by the sun, but the flow is much stronger. “Each decade, the red giant sheds enough hydrogen gas to equal the mass of Earth,” he added.

The white dwarf intercepts and captures some of this gas, which accumulates on its surface. As the gas piles on for decades to centuries, it eventually becomes hot and dense enough to fuse into helium. This energy-producing process triggers a runaway reaction that explodes the accumulated gas.

The white dwarf itself, however, remains intact.

The blast created a hot, dense expanding shell called a shock front, composed of high-speed particles, ionized gas and magnetic fields. According to an early spectrum obtained by Christian Buil at Castanet Tolosan Observatory, France, the nova’s shock wave expanded at 7 million miles per hour — or nearly 1 percent the speed of light.

The magnetic fields trapped particles within the shell and whipped them up to tremendous energies. Before they could escape, the particles had reached velocities near the speed of light. Scientists say that the gamma rays likely resulted when these accelerated particles smashed into the red giant’s wind.

“We know that the remnants of much more powerful supernova explosions can trap and accelerate particles like this, but no one suspected that the magnetic fields in novae were strong enough to do it as well,” said NRL’s Soebur Razzaque.

source : science journal

Finding the age of a galaxy

A key to generating the new number was knowledge that the earliest stars formed almost entirely from hydrogen. They lived short lives and exploded violently, spewing new and heavier elements into their surroundings.

The new age estimate is based on measurements of the element beryllium in two stars within a globular cluster of stars called NGC 6397. The amount of Beryllium, one of the lightest elements, increased with time and serves as a sort of “cosmic clock,” according to the team, led by Luca Pasquini of the European Southern Observatory.

The stars were found to be roughly 13.4 billion years old. The researchers added to that an interval of about 200 million years they say it took for previous generations of stars in the Milky Way to form, explode, and seed the fledgling galaxy with the goods necessary to forge the types of stars found in NGC 6397.

Radioactive dating of the elements Thorium 232 and Uranium 238 in one star put the galaxy at 14 billion years old, plus or minus 2.4 billion years. Examinations of the cooling rate of stellar corpses called white dwarfs yielded an age of 12.7 billion years, give or take 700 million years. And a look at when stars within clusters stopped shining in their primary “main sequence” phase set the age at 12.6 billion years, but with a possible range from 10.4 billion to 16 billion years.

PERSEIDS METEOR SHOWER TONIGHT

According to Nasa, the shower could produce a display of up to 80 meteors per hour.

“A waxing crescent moon will set before the shower becomes active, setting a perfect stage for meteor watching,” said the US space agency on its website.

Experts are urging people to head away from city lights for the best views.

John Mason from the British Astronomical Association (BAA) told BBC News: “Weather-permitting, we should be in for a very good show across the UK.

“The shower has been ongoing for a week now and we have already seen some very bright meteors whizzing overhead.”

The Perseid meteor shower is caused by debris from the comet Swift-Tuttle.

Every 133 years, the huge comet swings through the inner part of our Solar System and leaves behind a trail of dust and gravel.

When Earth passes through the debris, specks hit our atmosphere at 140,000mph and disintegrate in flashes of light.

The peak of the meteor shower occurs just two days after a new Moon, meaning that Earth’s natural satellite will not provide any extra light pollution to spoil the view.

The Royal Astronomical Society (RAS) said the relatively warm summer nights would make this meteor shower one of the more comfortable to watch.

The meteors are called the Perseids because they appear to fly out of the constellation Perseus

Wel, i m gonna watch now 😛

source : bbc

Dark energy vs Dark matter

Thanks to http://hetdex.org/dark_energy/dark_matter.php, its a very informative article

95% of universe is made up of Dark Energy(74%) + Dark matter (21%)
And remaining 5% consists of other known particles to human

my last reading says that Dark matter keeps the galaxy in a shape and is which helps hold the stars in a galaxy.
And now I see that Dark energy is just opposite to it and it helps the universe expand.

This image says the same thing – (source : above mentioned website)

But who will win in the end? Will all galaxy fade away soon becoz of Dark energy? if so then when?

Small Magellanic Cloud

Source

dark matter, dark energy, etc..

Did you know that unlike planets in a solar system, all stars in a galaxy rotates the galaxy’s center at same exact speed?
This is due to Dark matter says some scientists. In such case, why planets doesn’t work the same way ?!?!? Why one need to dig Kilometers under earth to prove such dark matter particle (like WIMP) then? I aint have a clue yet 😦

Scientist use type 1-A supernova’s to really see how galaxies moves – are they moving apart or they gonna collapse soon due to gravity.
The measurement is not an easy task since such supernova’s come and go in almost every galaxy. So they created a software to compare wide field images and see if any new explosion (suddenly brightening stars) – SN. And after measuring for about 5 years or so they see that its all moving apart (which means greater force more than gravity is present to move them apart) They call this the dark energy.

My question here is, solar system should be expanding too then ?

SN 1987A explosion : The first material to be ejected from the explosion traveled at an incredible 100 million km per hour, which is about a tenth of the speed of light or around 100 000 times faster than a passenger jet. Even at this breakneck speed it has taken 10 years to reach a previously existing ring of gas and dust puffed out from the dying star.

some astro data collection

milkyways dia – 100,000 light years
Earth’s width – 8,000 miles 8/100 inch
Sun’s width – 800,000 miles 8 inches
Jupiters width – 88 856.0805 miles
Next nearest star – proxima centuari – distance – 4.something light years
Oldest planet in Solarsystem – nothing is really very older than other. almost all formed around 4.3-4.7 billion years.
Sun’s life – 10 billion (already around 5 is over)
Earth – Sun distance – 147 million km (91 million miles).

diameter of Sun 1,400,000
distance from Sun to Mercury 58,000,000
diameter of Mercury 5,000
distance from orbit of Merury to Venus 50,000,000
diameter of Venus 12,000
distance from orbit of Venus to Earth 41,000,000
diameter of Earth 13,000
distance from orbit of Earth to Mars 78,000,000
diameter of Mars 7,000
distance from orbit of Mars to Jupiter 550,000,000
diameter of Jupiter 143,000
distance from orbit of Jupiter to Saturn 649,000,000
diameter of Saturn 120,00
distance from orbit of Saturn to Uranus 1,443,000,000
diameter of Uranus 51,000
distance from orbit of Uranus to Neptune 1,627,000,000
diameter of Neptune 49,000
distance from orbit of Neptune to Pluto 1,404,000,000
diameter of Pluto 2,300
total of distances 5,900,000,000

distance from Earth to Moon 384,000
diameter of Moon 3,500

Blowing in the Wind

Tokano re-analyzed a computer-based global circulation model for Titan he put together in 2008. That model, like others for Titan, was adapted from ones developed for Earth and Mars. Tokano added in new data on Titan topography and shape based on Cassini radar and gravity data. In his new analysis, Tokano also looked more closely at variations in the wind at different points in time rather than the averages. Equinox periods jumped out.

Equinoxes occur twice a Titan year, which is about 29 Earth years. During equinox, the sun shines directly over the
equator, and heat from the sun creates upwelling in the atmosphere. The turbulent mixing causes the winds to reverse and accelerate. On Earth, this rare kind of wind reversal happens over the Indian Ocean in transitional seasons between
monsoons.

The episodic reverse winds on Titan appear to blow around 1 to 1.8 meters per second (2 to 4 mph). The threshold for sand movement appears to be about 1 meter per second (2 mph), a speed that the typical east-to-west winds never appear to surpass. Dune patterns sculpted by strong, short episodes of wind can be found on Earth in the northern Namib sand seas in Namibia, Africa.

Sun’s color

The Sun’s color is white, although from the surface of the Earth it may appear yellow because of atmospheric scattering and
the sun is informally designated a yellow star, because most of its radiation is in the yellow-green portion of the visible
spectrum

Sun and CME picture

Sun emited huge amount of CME and created aurora at the earths poles. And this is the below pic how the sun looked on Aug3rd 2010 which might have caused the aurora

source