Eta Carinae in the news again

[DaveS]

Here

http://www.bbc.co.uk/news/science-environment-30721794

Really envy our southeren friends when that blows up.

[Beulah]

Brilliant stuff. Thanks for posting this. 

[ghostdance]

Wow...that must be some sight in the skies. Wonder how it compares to, say,  M42 naked eye & bins?

[Space_Ranger]

It's a shame most of the world's astronomers are in the Northern Hemisphere and can't see Eta Carinae

[Scosmico]

Wow...that must be some sight in the skies. Wonder how it compares to, say, M42 naked eye & bins?

I have been enjoing it this week during my holidays in Brazil.

Eta Carinae is a real treat in my travel scope nexstar 5se. it does not fit in my 40mm televue plossl.

Lovely nebulosity, clearer structures, quite big. Structure is seen fron binos (8x40) from dark skies.

My advice is:

Dont compare two or more pleasures, enjoy them.

A perfect night includes M42, eta Carinae, small and large magalanic clouds, coal sack and southern cross.

Regards

[Merlin66]

It was good to see the recognition of the Southern Hemisphere spectroscopy group - observers from New Zealand, Australia and Brazil.

Just shows what can be achieved with dedication and purpose.....

[ghostdance]

My advice is:

Dont compare two or more pleasures, enjoy them.

Absolutely agree

By 'compare' I meant only their visibility, not their excellence as objects...

I guess then that EC is an impressive sight naked eye and with some glass. I'd love to see it for myself some day!

[chops]

NASA's video, describing the interaction of the eccentric orbit & stellar winds in Eta Carinae's binary star system (see link), is one of the most interesting that I've watched for some time, I'd urge everyone to...

NASA Observatories Take an Unprecedented Look into Superstar Eta Carinae

http://www.nasa.gov/content/goddard/nasa-observatories-take-an-unprecedented-look-into-superstar-eta-carinae/#.VLDlL9ogGK1

Quote:

"Eta Carinae, the most luminous and massive stellar system within 10,000 light-years of Earth, is known for its surprising behavior, erupting twice in the 19th century for reasons scientists still don't understand. A long-term study led by astronomers at NASA's Goddard Space Flight Center in Greenbelt, Maryland, used NASA satellites, ground-based telescopes and theoretical modeling to produce the most comprehensive picture of Eta Carinae to date. New findings include Hubble Space Telescope images that show decade-old shells of ionized gas racing away from the largest star at a million miles an hour, and new 3-D models that reveal never-before-seen features of the stars' interactions.

"We are coming to understand the present state and complex environment of this remarkable object, but we have a long way to go to explain Eta Carinae's past eruptions or to predict its future behavior," said Goddard astrophysicist Ted Gull, who coordinates a research group that has monitored the star for more than a decade.

Located about 7,500 light-years away in the southern constellation of Carina, Eta Carinae comprises two massive stars whose eccentric orbits bring them unusually close every 5.5 years. Both produce powerful gaseous outflows called stellar winds, which enshroud the stars and stymy efforts to directly measure their properties. Astronomers have established that the brighter, cooler primary star has about 90 times the mass of the sun and outshines it by 5 million times. While the properties of its smaller, hotter companion are more contested, Gull and his colleagues think the star has about 30 solar masses and emits a million times the sun's light.

At closest approach, or periastron, the stars are 140 million miles (225 million kilometers) apart, or about the average distance between Mars and the sun. Astronomers observe dramatic changes in the system during the months before and after periastron. These include X-ray flares, followed by a sudden decline and eventual recovery of X-ray emission; the disappearance and re-emergence of structures near the stars detected at specific wavelengths of visible light; and even a play of light and shadow as the smaller star swings around the primary.

During the past 11 years, spanning three periastron passages, the Goddard group has developed a model based on routine observations of the stars using ground-based telescopes and multiple NASA satellites. "

Seen in blue light emitted by doubly ionized iron atoms (4,659 angstroms), these images of Eta Carinae were captured by Hubble's STIS instrument between 2010 and 2014. Gas shells created during the binary's 2003 close approach race outward at about 1 million mph (1.6 million km/h).

Image Credit: NASA's Goddard Space Flight Center/T. Gull et al.

Eta Carinae's great eruption in the 1840s created the billowing Homunculus Nebula, imaged here by Hubble. Now about a light-year long, the expanding cloud contains enough material to make at least 10 copies of our sun. Astronomers cannot yet explain what caused this eruption.

Image Credit: NASA, ESA, and the Hubble SM4 ERO Team

According to this model, the interaction of the two stellar winds accounts for many of the periodic changes observed in the system. The winds from each star have markedly different properties: thick and slow for the primary, lean and fast for the hotter companion. The primary's wind blows at nearly 1 million mph and is especially dense, carrying away the equivalent mass of our sun every thousand years. By contrast, the companion's wind carries off about 100 times less material than the primary's, but it races outward as much as six times faster."

And, just for the sake of it, here's Hubble's Eta Carinae image:

[astropa]

Great stuff. Interesting that both articles state that  "Eta Carinae is 7,500 light years from Earth - and it is the biggest star within 10,000." Im not sure which stars are bigger at greater distances. 90 solar masses seems to be at the lower end of its mass range too. Ive seen everything up to 150 solar