APOD: Doomed Star Eta Carinae (2015 Dec 27)

[APOD Robot]

Doomed Star Eta Carinae

Explanation: Eta Carinae may be about to explode. But no one knows when - it may be next year, it may be one million years from now. Eta Carinae's mass - about 100 times greater than our Sun - makes it an excellent candidate for a full blown supernova. Historical records do show that about 150 years ago Eta Carinae underwent an unusual outburst that made it one of the brightest stars in the southern sky. Eta Carinae, in the Keyhole Nebula, is the only star currently thought to emit natural LASER light. This featured image, taken in 1996, brought out new details in the unusual nebula that surrounds this rogue star. Now clearly visible are two distinct lobes, a hot central region, and strange radial streaks. The lobes are filled with lanes of gas and dust which absorb the blue and ultraviolet light emitted near the center. The streaks remain unexplained.

<< Previous APOD

This Day in APOD

Next APOD >>

[/b]

[ta152h0]

maybe the first target for the new Webb telescope when deployed ?

[Chris Peterson]

This featured image, taken in 1996, brought out new details in the unusual nebula that surrounds this rogue star.

I don't believe this star has any of the characteristics that would generally identify it as a "rogue star", being located in a normal position and orbit within our galaxy.

[Ann]

This featured image, taken in 1996, brought out new details in the unusual nebula that surrounds this rogue star.

I don't believe this star has any of the characteristics that would generally identify it as a "rogue star", being located in a normal position and orbit within our galaxy.

Wikipedia wrote:
A rogue star, primarily known as an intergalactic star, is a star that has escaped the gravitational pull of its home galaxy and is moving independently in or towards the intergalactic void. More loosely, any star in an unusual location or state of motion may be termed a rogue star.

The rogue star link in today's caption takes us to a page which says:

Previous models of such bipolar flows predict a dense disk surrounding the star which funnels the ejected material out of the poles of the system. In Eta Carinae, however, high velocity material is spraying out in the same plane as the hypothetical disk, which is supposed to be channeling the flow.

To me, the Homunculus Nebula (the nebula made of ejected material surrounding Eta Carinae) looks a bit like a fat and misshapen baby. The big lobe turned toward us is the "body", the somewhat darker lobe turned away from us is the "head", and the stubby jets of material sticking out at the sides are the arms.

These jets are clearly spraying out through holes in the (hypothetical) disk. Do we really know that the disk is there, and that there is something "wrong" or at least "strange" with the direction of the outflow of the jets?

Ann

[bjmb]

Historical records do show that about 150 years ago Eta Carinae underwent an unusual outburst that made it one of the brightest stars in the southern sky.

you mean to say: "Historical records do show that about 150 years ago Eta Carinae was noticed to have undergone an unusual outburst that made it one of the brightest stars in the southern sky."

[neufer]

This featured image, taken in 1996, brought out new details in the unusual nebula that surrounds this rogue star.

I don't believe this star has any of the characteristics that would generally identify it as a "rogue star", being located in a normal position and orbit within our galaxy.

A rogue star... is any star in an unusual location or state of motion may be termed a rogue star.

Besides which...Eta Carinae is not really a star but rather "a stellar system containing at least two stars."

<<A rogue is a vagrant person who wanders from place to place. Like a drifter, a rogue is an independent person who rejects conventional rules of society in favor of following their own personal goals and values. The [modern] term rogue is used pejoratively to describe a dishonest or unprincipled person whose behavior one disapproves of, but who is nonetheless likeable and/or attractive.>>

Well...Eta Carinae is certainly attractive although we disapprove of its behavior.

[Chris Peterson]

Historical records do show that about 150 years ago Eta Carinae underwent an unusual outburst that made it one of the brightest stars in the southern sky.

you mean to say: "Historical records do show that about 150 years ago Eta Carinae was noticed to have undergone an unusual outburst that made it one of the brightest stars in the southern sky."

I prefer the first, as a shorter and clearer statement of what occurred.

[bjmb]

'shorter', sure, but its 'clarity' is false - what 'occurred' 150 years ago with the real eta carinae is unknown, what we noticed and notice is always some 7,000 year old news. perhaps it's been a supernova for the past 6,000 years - we won't know until a thousand years hence.

[geckzilla]

Heh, I dunno why people get so caught up on using local time to describe when astronomical events occur. I mean, I get why, but at the same time, it's a given that distant objects have a noticeable light travel time. Mentioning it over and over is just redundant.

[Chris Peterson]

'shorter', sure, but its 'clarity' is false - what 'occurred' 150 years ago with the real eta carinae is unknown, what we noticed and notice is always some 7,000 year old news. perhaps it's been a supernova for the past 6,000 years - we won't know until a thousand years hence.

We treat the event as occurring when it is observed, because that is the most natural way given the nature of spacetime.

[Ann]

Art wrote:
Besides which...Eta Carinae is not really a star but rather "a stellar system containing at least two stars."

So, do you often call Albireo a stellar system containing at least two stars? Okay, Albireo is very well-known for being a a colorful yellow and blue double star. But do you often call Albireo A, the bright yellow component, a stellar system containing at least two stars?

Jim Kaler wrote:
Albireo is actually triple. The brighter yellow-colored member, Albireo A, is a much closer double made of a third magnitude (3.3) class K (K3) stable helium-fusing bright giant and a hotter but dimmer (magnitude 5.5) class B (B9) hydrogen-fusing dwarf, the two stars not readily separable in the telescope.

The term for a stellar system containing two stars is normally "binary star".

Ann

[geckzilla]

I don't think the nature of Eta Carinae makes it easy to determine just how many stars are in its system. The second was inferred but only recently directly detected. This star system has a lot of baggage to deal with.

[ddanbe]

I find it a strange coincidence that the nebula around this star resembles one of the d-orbitals of an atom.
Anyone any comments?

[RedFishBlueFish]

Historical records do show that about 150 years ago Eta Carinae underwent an unusual outburst that made it one of the brightest stars in the southern sky.

you mean to say: "Historical records do show that about 150 years ago Eta Carinae was noticed to have undergone an unusual outburst that made it one of the brightest stars in the southern sky."

I prefer the first, as a shorter and clearer statement of what occurred.

Moreover, if one strives for pedantic correctness, certainly one simply must add at least one additional superfluous phrase such as "...of one planet of a star in the Orion-Cygnus arm of the Milky Way approximately 7500 light-years distant from Eta Carinae nee Argus"

Happy New Year (as locally determined on that same body)!

[neufer]

---

I find it a strange coincidence that the nebula around this star resembles one of the d-orbitals of an atom.
Anyone any comments?

• It is the classical shape
  of an axially symmetric
  quadrupole moment

[bystander]

APOD: Doomed Star Eta Carinae (2012 Dec 30) - http://asterisk.apod.com/viewtopic.php?f=9&t=30441

[winstond]

Why does everyone seem so cranky today? Chill and enjoy the image folks, 'tis the season of goodwill.

[neufer]

• Why does everyone seem so cranky today?
  Chill and enjoy the image folks, 'tis the season of goodwill.

--------------------------------------------------------------------
DOOM : ANAGKH : FATE
....................................................................
PREFACE. _The Hunchback of Notre Dame_ by Victor Hugo

• A few years ago, while visiting or, rather, rummaging about Notre-Dame, the author of this book found, in an obscure nook of one of the towers, the following word, engraved by hand upon the wall:--

~ ANAGKH ~

• These Greek capitals, black with age, and quite deeply graven in the stone, with I know not what signs peculiar to Gothic caligraphy imprinted upon their forms and upon their attitudes, as though with the purpose of revealing that it had been a hand of the Middle Ages which had inscribed them there, and especially the fatal & melancholy meaning contained in them, struck the author deeply. He questioned himself; he sought to divine who could have been that soul in torment which had not been willing to quit this world without leaving this stigma of crime or unhappiness upon the brow of the ancient church. Afterwards, the wall was whitewashed or scraped down, I know not which, and the inscription disappeared. For it is thus that people have been in the habit of proceeding with the marvellous churches of the Middle Ages for the last two hundred years. Mutilations come to them from every quarter, from within as well as from without. The priest whitewashes them, the archdeacon scrapes them down; then the populace arrives and demolishes them.

It is upon this word that this book is founded. -- Victor Hugo March, 1831
---------------------------------------------------------------------------------------

[ta152h0]

some enjoy the image simply by looking at it, others by analyzing the beejeebers out of it. Everyday people .....

[Ron-Astro Pharmacist]

---

I find it a strange coincidence that the nebula around this star resembles one of the d-orbitals of an atom.
Anyone any comments?

• It is the classical shape
  of an axially symmetric
  quadrupole moment

Does anyone know what shape is represented if you subtract a torus from a sphere? To me it would be shaped liked a wormhole plus a little left over (as the remainder of the sphere). Of course there are many torus-shapes but" in general" I'm asking is there a named geometrical shape for the part that is not the torus

[captainwiggins48]

Heh, I dunno why people get so caught up on using local time to describe when astronomical events occur. I mean, I get why, but at the same time, it's a given that distant objects have a noticeable light travel time. Mentioning it over and over is just redundant.

Is it a 'given' that a photon can survive unperturbed, at a constant speed for 7,000 or 7 billion years? How did it get here seemingly under it's own power and where does it get it's sustainability? This question needs to be addressed, but I fear that many in the scientific community aren't ready for the answer. Until the nomenclature specifies the time evolution of events ("light year" may be archaic) we'll have to continually be mindful of local versus ancient 'time'.

[Chris Peterson]

Heh, I dunno why people get so caught up on using local time to describe when astronomical events occur. I mean, I get why, but at the same time, it's a given that distant objects have a noticeable light travel time. Mentioning it over and over is just redundant.

Is it a 'given' that a photon can survive unperturbed, at a constant speed for 7,000 or 7 billion years?

Yes.

How did it get here seemingly under it's own power and where does it get it's sustainability? This question [sic] needs to be addressed, but I fear that many in the scientific community aren't ready for the answer.

This has been addressed. It is understood, outside of pseudoscience, quackery, and Internet cranks.

[geckzilla]

Until the nomenclature specifies the time evolution of events ("light year" may be archaic) we'll have to continually be mindful of local versus ancient 'time'.

You can, but you're not going to force that view on us here.

[Glima49]

I noticed in the light curve that around 1940 Eta Carinae experienced another brightening that continues to this day. Wonder if this means another Great Eruption? In any case, I can't wait for Betelgeuse, Eta Carinae or Sher 25 to either outburst dramatically again or blow up in a supernova.

[neufer]

I noticed in the light curve that around 1940 Eta Carinae experienced another brightening that continues to this day. Wonder if this means another Great Eruption? In any case, I can't wait for Betelgeuse, Eta Carinae or Sher 25 to either outburst dramatically again or blow up in a supernova.

• Then try saying their names 3 times in a row.

<<Betelgeuse (better known as Beetlejuice) is a trickster and mischievous ghost who can be summoned if his name is said 3 times in a row. According to Betelgeuse, he attended Julliard, is a graduate of the Harvard Business School, traveled quite extensively, lived through the Black Plague (and had a pretty good time during that), and has seen The Exorcist about 167 times (AND IT KEEPS GETTING FUNNIER EVERY SINGLE TIME).