APOD: Zeta Oph: Runaway Star (2012 Dec 29)

Post a reply


This question is a means of preventing automated form submissions by spambots.
Smilies
:D :) :ssmile: :( :o :shock: :? 8-) :lol2: :x :P :oops: :cry: :evil: :roll: :wink: :!: :?: :idea: :arrow: :| :mrgreen:
View more smilies

BBCode is ON
[img] is ON
[url] is ON
Smilies are ON

Topic review
   

Expand view Topic review: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by Raven » Thu Jan 17, 2013 12:41 pm

ta152h0 wrote:...a really big kaboom like the Big Bang and this star has been traveling ever since, in various forms ?
gypsy of a strange and distant time
traveling in panic, all direction blind ...
oh oh, oh oh oh oh oh oh
oh oh, oh oh oh oh oh oh
left without a hope of coming home


-- Justin Hayward / Moody Blues

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by ta152h0 » Sun Dec 30, 2012 10:17 pm

maybe a hypernovae ????? a really big kaboom like the Big Bang and this star has been traveling ever since, in various forms ? or not !

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by BDanielMayfield » Sun Dec 30, 2012 2:29 pm

Ann wrote:
BDanielMayfield wrote:
neufer wrote:And what if it also caused critical mutations to our DNA that led to ...
I respectfully disagree with that speculative suggestion, since I’m personally convinced that our appearance as a species was intentional rather than accidental. That being said, I have no reason to disbelieve that a relatively nearby supernova occurred about 3 MYA, or that it could have had a significant effect upon this planet and the life upon it. I wonder, is there any evidence of paleio-climatic changes or is there any fossil evidence for any changes on the earth around this time?

Bruce
You should probably ask someone else, but I strongly believe that the supernova that sent Zeta Ophiuchi flying happened too far away to really affect the Earth. According to my software, the distance to Zeta Ophiuchi today is 366 ± 8 light-years, clearly suggesting that the distance is not greater than 400 light-years. The other stars of upper Scorpius, however, appear to be typically at least 500 light-years away. It would appear, therefore, that the runaway Zeta Ophiuchi might be approaching us, so that it was farther away than it is now by the time its companion went supernova. Anyway, a distance of about 400 light-years is probably quite safe for a Type II supernova.

On the other hand, I believe that astronomers think that the solar system was born from a gas cloud that had been enriched by elements from a recent supernova. So we are indeed the children of supernovae.

Ann
Ann, first let me correct my failure to thank you for that detailed answer you provided to one of my initial questions in this thread. After reading what you wrote I can see now that estimating the power of the future blast of Zeta Oph when it goes SN would be fraught with much uncertainty.

As the discussion progressed however I became much more interested in the past rather than the future with regard to this star and its one time binary companion. The reason for this can be found in the Wikipedia article on Zeta Ophuichi (I apologize for not providing a link). In this article you will find that the radial velocity of this star is listed as negative 15 km/s. Therefore this star is found to be rapidly receding, and not approaching as you suggested in your last comment. So this is good news for anything living on earth in the 4 or so million years when it follows the fate of its former partner.

So the question then becomes how close may the SN that launched Zeta Oph have been to the earth 3 MYA? As you state the distance to Zeta Oph now is about 366 ly. The above referenced Wiki article also lists it’s peculiar (that is actual) velocity as being 30 km/s. Multiplying that by 3 MYA yields approximately 300 ly. So we have two sides of an irregular triangle and if we can estimate the angle between these lines we can then calculate the estimated distance between where the earth is now and where Zeta Oph was 3 MYA when its companion popped.

The Wiki article also lists the proper motions in Right Ascension and in Declination as being +15.26 and +24.79 in milliarcseconds per year. Someone with somewhat more math skills and or time than I should be able to do the calculation with this set of givens, I would think. Once we have solved for the distance stated in the last sentence of my previous paragraph then we would simply need to account for the sun’s motion backwards 3 MYA and we would then have a fairly good answer as to how far away from earth this SN was. I can not imagine that this hasn’t already been done, since even someone like me can conceive of how to arrive at the solution.

In short though Ann, since Zeta Oph is receding from us, I do think that the SN that launched it could indeed have been the one that nuefer referenced. If so then you and I and likely everyone else as well as this runaway star share atoms that were created in this supernova blast, which I think is a very nice connection.

Bruce

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by Ann » Sun Dec 30, 2012 6:33 am

BDanielMayfield wrote:
neufer wrote:And what if it also caused critical mutations to our DNA that led to ...
I respectfully disagree with that speculative suggestion, since I’m personally convinced that our appearance as a species was intentional rather than accidental. That being said, I have no reason to disbelieve that a relatively nearby supernova occurred about 3 MYA, or that it could have had a significant effect upon this planet and the life upon it. I wonder, is there any evidence of paleio-climatic changes or is there any fossil evidence for any changes on the earth around this time?

Bruce
You should probably ask someone else, but I strongly believe that the supernova that sent Zeta Ophiuchi flying happened too far away to really affect the Earth. According to my software, the distance to Zeta Ophiuchi today is 366 ± 8 light-years, clearly suggesting that the distance is not greater than 400 light-years. The other stars of upper Scorpius, however, appear to be typically at least 500 light-years away. It would appear, therefore, that the runaway Zeta Ophiuchi might be approaching us, so that it was farther away than it is now by the time its companion went supernova. Anyway, a distance of about 400 light-years is probably quite safe for a Type II supernova.

On the other hand, I believe that astronomers think that the solar system was born from a gas cloud that had been enriched by elements from a recent supernova. So we are indeed the children of supernovae.

Ann

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by BDanielMayfield » Sun Dec 30, 2012 5:31 am

neufer wrote:And what if it also caused critical mutations to our DNA that led to ...
I respectfully disagree with that speculative suggestion, since I’m personally convinced that our appearance as a species was intentional rather than accidental. That being said, I have no reason to disbelieve that a relatively nearby supernova occurred about 3 MYA, or that it could have had a significant effect upon this planet and the life upon it. I wonder, is there any evidence of paleio-climatic changes or is there any fossil evidence for any changes on the earth around this time?

Bruce

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by bboyne3 » Sun Dec 30, 2012 4:17 am

Dear APOD,

I do not know if you photoshop, but I see a gorgeous woman who is now my screen saver.

regards,

bill

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by neufer » Sun Dec 30, 2012 3:38 am

BDanielMayfield wrote:
That’s a fascinating tidbit that you highlight at the end of your very informative post, neufer. We are made from the dust of the earth, but the dust of the earth was made from star stuff, as Sagan was fond of saying. It seems very possible and perhaps likely that the supernova blast that sent today’s apod star flying upon its runaway path around 3 million years ago is the very one that dusted the earth with enough “star stuff” that it can still be measured today in sediments at the bottom of the seas. If this is the case then it would be very likely that most and maybe all humans alive today have at least a few and maybe even many atoms from this supernova inside our bodies right now. I think this puts today’s apod in a more personal perspective than most, don’t you think?
And what if it also caused critical mutations to our DNA that led to Homo habilis.
http://en.wikipedia.org/wiki/Human_accelerated_regions

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by BDanielMayfield » Sat Dec 29, 2012 10:48 pm

neufer wrote:
Boomer12k wrote:
I don't see a supernova remnant anywhere nearby... The other could now be a small dwarf star, or even a black hole and traveling along too close to see maybe, or it just got blown away, and then Zeta Oph would just have "continued on its way". But I don't see an S.R. anywhere nearby, and I suppose it could be obscured by denser dust in another part of the nebulosity.
After ~40,000 years there is not much left of a supernova remnant to observe and we would likely be inside of any remnant this close. One must look rather for pulsars. :arrow:
http://en.wikipedia.org/wiki/Zeta_Ophiuchi wrote:
<<ζ Ophiuchi is moving through space with a peculiar velocity of 30 km/s. Based upon the age and direction of motion of this star, it is a member of the Upper Scorpius sub-group of the Scorpius-Centaurus Association of stars that share a common origin and space velocity. Such runaway stars may be ejected by dynamic interactions between three or four stars. However, in this case the star may be a former component of a binary star system in which the more massive primary was destroyed in a Type II supernova explosion. The pulsar PSR B1929+10 may be the leftover remnant of this supernova, as it too was ejected from the association with a velocity vector that fits the scenario.>>
http://en.wikipedia.org/wiki/Scorpius-Centaurus_Association wrote:

<<The Scorpius-Centaurus Association (sometimes called Sco-Cen or Sco OB2) is the nearest OB Association to the Sun. This stellar association is composed of three subgroups (Upper Scorpius, Upper Centaurus-Lupus, and Lower Centaurus-Crux), whose mean distances range from 380 to 470 light years.

Many of the bright stars in the constellations Scorpius, Lupus, Centaurus, and Crux are members of the Sco-Cen association, including Antares (the most massive member of Upper Scorpius), and most of the stars in the Southern Cross. The Sco-Cen OB association appears to be the most pronounced part of a large complex of recent (<20 million years) and ongoing star-formation. The complex contains several star-forming molecular clouds in Sco-Cen's immediate vicinity—the Rho Oph, Pipe Nebula, Barnard 68, Chamaeleon, Lupus, Corona Australis, and Coalsack cloud complexes (all at distances of ~120-200 parsecs), and several less populous, young stellar groups on the periphery of Sco-Cen, including the ~3-5 million-year-old epsilon Cha group, ~7 million-year-old eta Chamaeleontis cluster (also called Mamajek 1), ~8 million-year-old TW Hydrae association, ~12 million-year-old Beta Pictoris moving group, and possibly the ~30-50 million-year-old IC 2602 open cluster.

The stellar members of the Sco-Cen association have convergent proper motions of approximately 0.02-0.04 arcseconds per year, indicative that the stars have nearly parallel velocity vectors, moving at about 20 km/s with respect to the Sun. The dispersion of the velocities within the subgroups are only of order 1–2 km/s, and the group is most likely gravitationally unbound. Several supernovae have exploded in Sco-Cen over the past 15 million years, leaving a network of expanding gas superbubbles around the group, including the Loop I Bubble. To explain the presence of radioactive 60Fe in deep ocean ferromanganese crusts, it has been hypothesized that a nearby supernova, possibly a member of Sco-Cen, exploded in the Sun's vicinity roughly 3 million years ago.>>
That’s a fascinating tidbit that you highlight at the end of your very informitive post, neufer. We are made from the dust of the earth, but the dust of the earth was made from star stuff, as Sagan was fond of saying. It seems very possible and perhaps likely that the supernova blast that sent today’s apod star flying upon its runaway path around 3 million years ago is the very one that dusted the earth with enough “star stuff” that it can still be measured today in sediments at the bottom of the seas. If this is the case then it would be very likely that most and maybe all humans alive today have at least a few and maybe even many atoms from this supernova inside our bodies right now. I think this puts today’s apod in a more personal perspective than most, don’t you think?

I'm glad that Zeta Oph is a naked eye star that will be so easy to find right above the great Scorpion and to the right of the tea pot asterism that helps me find the center of the Milky Way. Today's Apod and what I have learned about Zeta Oph will contribute to my star gazing enjoyment for many nights to come, I am sure.

Bruce

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by ta152h0 » Sat Dec 29, 2012 8:42 pm

This must be voted APOD of the Year. The Big Poobah in the Sky has to be proud of his creation. Hey Charlie Brown, there is a Great Pumpkin

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by Chris Peterson » Sat Dec 29, 2012 8:35 pm

Boomer12k wrote:I don't see a supernova remnant anywhere nearby. But maybe it is too faint now.
It is almost certain that no detectable supernova remnant remains. Remnants dissipate very rapidly- a few tens of thousands of years is as long as they exist. It's likely that the companion supernova that isolated this star occurred more than a million years ago. The most we could hope to detect would be some sort of cool, compact body, and it's doubtful we could do so for technical reasons.
I am thinking that if a larger companion exploded, then THIS would become the more massive, and the companion would now be dragged along with Zeta Oph.
No, that is dynamically impossible. The center of mass of the entire system must be close to where it always was. Supernovas release anywhere from ~1% to ~15% of their rest mass as energy. So even the most energetic core-collapse supernova will still retain at least 85% of its mass after the explosion. Much will be dissipated fairly symmetrically in the remnant nebula. The core body will remain in substantially the same place (perhaps with a small velocity imparted by an asymmetrical explosion). The companion was ejected because of the nature of orbital dynamics. In a suitable orbit, a rapid change in the mass and position of the body it was orbiting could substantially shift the angular momentum of the system between different bodies, and allow the companion to achieve escape velocity.

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by rr_carroll » Sat Dec 29, 2012 7:38 pm

Thanks, all. This is showing the approximate nature of many astronomical values, which I should have been aware of already. :)

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by neufer » Sat Dec 29, 2012 7:31 pm

Boomer12k wrote:
I don't see a supernova remnant anywhere nearby... The other could now be a small dwarf star, or even a black hole and traveling along too close to see maybe, or it just got blown away, and then Zeta Oph would just have "continued on its way". But I don't see an S.R. anywhere nearby, and I suppose it could be obscured by denser dust in another part of the nebulosity.
After ~40,000 years there is not much left of a supernova remnant to observe and we would likely be inside of any remnant this close. One must look rather for pulsars. :arrow:
http://en.wikipedia.org/wiki/Zeta_Ophiuchi wrote:
<<ζ Ophiuchi is moving through space with a peculiar velocity of 30 km/s. Based upon the age and direction of motion of this star, it is a member of the Upper Scorpius sub-group of the Scorpius-Centaurus Association of stars that share a common origin and space velocity. Such runaway stars may be ejected by dynamic interactions between three or four stars. However, in this case the star may be a former component of a binary star system in which the more massive primary was destroyed in a Type II supernova explosion. The pulsar PSR B1929+10 may be the leftover remnant of this supernova, as it too was ejected from the association with a velocity vector that fits the scenario.>>
http://en.wikipedia.org/wiki/Scorpius-Centaurus_Association wrote:

<<The Scorpius-Centaurus Association (sometimes called Sco-Cen or Sco OB2) is the nearest OB Association to the Sun. This stellar association is composed of three subgroups (Upper Scorpius, Upper Centaurus-Lupus, and Lower Centaurus-Crux), whose mean distances range from 380 to 470 light years.

Many of the bright stars in the constellations Scorpius, Lupus, Centaurus, and Crux are members of the Sco-Cen association, including Antares (the most massive member of Upper Scorpius), and most of the stars in the Southern Cross. The Sco-Cen OB association appears to be the most pronounced part of a large complex of recent (<20 million years) and ongoing star-formation. The complex contains several star-forming molecular clouds in Sco-Cen's immediate vicinity—the Rho Oph, Pipe Nebula, Barnard 68, Chamaeleon, Lupus, Corona Australis, and Coalsack cloud complexes (all at distances of ~120-200 parsecs), and several less populous, young stellar groups on the periphery of Sco-Cen, including the ~3-5 million-year-old epsilon Cha group, ~7 million-year-old eta Chamaeleontis cluster (also called Mamajek 1), ~8 million-year-old TW Hydrae association, ~12 million-year-old Beta Pictoris moving group, and possibly the ~30-50 million-year-old IC 2602 open cluster.

The stellar members of the Sco-Cen association have convergent proper motions of approximately 0.02-0.04 arcseconds per year, indicative that the stars have nearly parallel velocity vectors, moving at about 20 km/s with respect to the Sun. The dispersion of the velocities within the subgroups are only of order 1–2 km/s, and the group is most likely gravitationally unbound. Several supernovae have exploded in Sco-Cen over the past 15 million years, leaving a network of expanding gas superbubbles around the group, including the Loop I Bubble. To explain the presence of radioactive 60Fe in deep ocean ferromanganese crusts, it has been hypothesized that a nearby supernova, possibly a member of Sco-Cen, exploded in the Sun's vicinity roughly 3 million years ago.>>

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by BDanielMayfield » Sat Dec 29, 2012 7:17 pm

rr_carroll wrote:
Boomer12k wrote:I don't see a supernova remnant anywhere nearby. But maybe it is too faint now. I am thinking that if a larger companion exploded, then THIS would become the more massive, and the companion would now be dragged along with Zeta Oph. It would not have been "Flung" out of the system. It would just become the dominant mass of the system. The other could now be a small dwarf star, or even a black hole and traveling along too close to see maybe, or it just got blown away, and then Zeta Oph would just have "continued on its way". But I don't see an S.R. anywhere nearby, and I suppose it could be obscured by denser dust in another part of the nebulosity...
I was thinking along the same lines as Boomer12k - follow Zeta Oph's track backward and see if it passes near a supernova remnant. When I followed the links in the story, this seems to have been done for some runaway stars. But links to supernova info say that the supernova explosion can be assymetrical, so the SNR could recoil from the blast. I suppose it could gain a new velocity of unknown speed and direction. Still, it might be possible to find an SNR that's consistent with Zeta Oph's speed, distance and timing. I assume the companion SNR would have been mentioned if it were known.

Let's see, the last link in the story implies that Zeta Oph is about 4 million years old. At 24 km./sec. X 31 million sec/yr. X 4,000,000 yr. = about 3 X 10 to the 15th power kilometers moved since the explosion. So Zeta Oph has moved (3 X 10 to 15th km.) X (9.5 trillion km./light-year) = 316 light-years since the explosion. Since it's 460 l.y. away, it's moved about arctan(316/460) = 34 degrees across the sky, unless my math is wrong. Assuming the remnant's speed is the same or less, you'd have a circle of sky to search that's 68 degrees across. At least, it's within a thousand l.y. from us, which is pretty close.

Boomer12k, unless you have a very large telescope, I presume you did not "see" a consistent supernova remnant in a list of them. I'm curious to know what that list is.
This is a very interesting discussion. I found these statements in the Wikipedia article on Zeta Ophiuchi which may be of help, (or, add to the confusion):

“This is a young star with an age of only three million years.”

If that’s true then it wasn’t even around 4 million years ago.

"ζ Ophiuchi is moving through space with a peculiar velocity of 30 km s–1. Based upon the age and direction of motion of this star, it is a member of the Upper Scorpius sub-group of the Scorpius-Centaurus Association of stars that share a common origin and space velocity.[5] Such runaway stars may be ejected by dynamic interactions between three or four stars. However, in this case the star may be a former component of a binary star system in which the more massive primary was destroyed in a Type II supernova explosion. The pulsar PSR B1929+10 may be the leftover remnant of this supernova, as it too was ejected from the association with a velocity vector that fits the scenario (within a margin of error).[3]"

So, if you want to find the supernova remains Boomer12k, locate pulsar PSR B1929+10 and then backtrack it and Zeta Oph’s paths back to see where (and when) they converge.

Bruce

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by BDanielMayfield » Sat Dec 29, 2012 7:12 pm

Thanks neufer. Now corrected.

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by rr_carroll » Sat Dec 29, 2012 7:11 pm

CMatisse, Zeta Oph is moving about 24 km./sec X 31,000,000 sec./yr. = 744 million km./yr. It's distance is about 460 light-years X 9.5 trillion km./l.y. = 4.37 quadrillion km. So it moves about arctan(744 million km./4.37 quadrillion km.) = 0.000000170 degrees across the sky in a year, which is 0.000000170 degree X 3600 sec. of arc/degree = 0.0006.1 sec. of arc/yr. So it takes about 1,600 years to see a change of 1 sec. of arc.

Edit: Oops! According to the Hipparchos values cited by BDanielMayfield, the proper motion I calc'ed (0.6 milliarcsec/yr.) is about 50 times to small! So it should "only" take about 32 years to see 1 arcsec of movement.

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by Ann » Sat Dec 29, 2012 7:09 pm

BDanielMayfield wrote:
This leads to 2 questions: (1) How big will the blast be when Zeta Oph pops off? Or equivallently, what percentage of it’s mass will be converted into energy? (2) How far away from the Earth will this star be in 4 milion years?
Good questions. I have no idea how far away it will be from the Earth in 4 million years. As to how intrinsically bright the supernova explosion will be, there are a few things to keep in mind. First of all, it will be a supernova type II explosion, a core-collapse supernova. In all probability, the supernova explosion will not give rise to a black hole, which means that the core of the star will become a neutron star, with a probable mass of a bit more than 1.4 solar masses.

So how much of Zeta Ophiuchi's mass will be converted into energy? Today the star probably contains about 20 solar masses. Perhaps 1.5 solar masses will go into making a neutron star. Does that mean that the other 18.5 solar masses will be converted into energy?

No, that will not happen. It is almost certain that Zeta Ophiuchi will lose a lot of mass through a strong stellar wind before it goes supernova. There is some evidence, or at least some suggestion, that very massive stars often don't make extremely bright supernovae, because they lose so much mass through their own stellar wind before they pop. An example of a star which has really "lost weight" is the Wolf-Rayet component of Gamma Velorum. Jim Kaler wrote about this star:
The windy WR star probably started with somewhere around 40 solar masses and has now stripped itself down by an unknown amount, perhaps to under 10.
Zeta Ophiuchi will almost certainly not lose three quarters of its own mass before it explodes, but it will certainly lose mass. How much mass it loses and how much it retains will determine how bright it will become when it explodes.

An interesting example of a mass-loss star that went supernova is the progenitor of Supernova 1987A. Before this supernova exploded in the Large Magellanic Cloud, it was a truism among astronomers that only red supergiant stars exploded as supernovae. But because the LMC is so nearby, the progenitor of the supernova had been photographed and classified before it popped and could be identified as a blue supergiant of spectral class B3. However, it was soon understood that the star, Sanduleak -69° 202, had previously been a red supergiant and had turned blue by shedding a lot of mass and shrinking. This meant that even though the core of Sanduleak -69° 202 was ripe for an explosion, the star as a whole was underweight. Therefore the explosion was unusually faint.
http://en.wikipedia.org/wiki/SN_1987A wrote:
It is of note that the supernova of the blue giant Sanduleak -69° 202 was about one-tenth as luminous as the average observed type II supernova, which is associated with the denser makeup of the star
So it is anybody's guess, actually, how bright the Zeta Ophiuchi supernova will be when it explodes.

Ann

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by neufer » Sat Dec 29, 2012 6:51 pm

BDanielMayfield wrote:
CMatisse wrote:
Since it is moving so fast, does this mean it is in a different position every night?
No CMatisse. Since it’s so far away it, like almost all other stars takes an extremely long time (in human terms) to change apparent position relative to other stars. Wikipedia lists it’s proper motions as +15.26 and +24.79 mas/yr in RA and Dec respectively, with mas meaning minute arc seconds. A minute arc second is only 1/3600th of 1 degree, and 1 degree is only 1/180th of the distance across the entire sky.
Correct... except that that should read milliarcsecond rather than minute arc second

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by astronomy » Sat Dec 29, 2012 6:44 pm

rr_carroll wrote:
Boomer12k wrote:I don't see a supernova remnant anywhere nearby. But maybe it is too faint now. I am thinking that if a larger companion exploded, then THIS would become the more massive, and the companion would now be dragged along with Zeta Oph. It would not have been "Flung" out of the system. It would just become the dominant mass of the system. The other could now be a small dwarf star, or even a black hole and traveling along too close to see maybe, or it just got blown away, and then Zeta Oph would just have "continued on its way". But I don't see an S.R. anywhere nearby, and I suppose it could be obscured by denser dust in another part of the nebulosity...
I was thinking along the same lines as Boomer12k - follow Zeta Oph's track backward and see if it passes near a supernova remnant. When I followed the links in the story, this seems to have been done for some runaway stars. But links to supernova info say that the supernova explosion can be assymetrical, so the SNR could recoil from the blast. I suppose it could gain a new velocity of unknown speed and direction. Still, it might be possible to find an SNR that's consistent with Zeta Oph's speed, distance and timing. I assume the companion SNR would have been mentioned if it were known.

Let's see, the last link in the story implies that Zeta Oph is about 4 million years old. At 24 km./sec. X 31 million sec/yr. X 4,000,000 yr. = about 3 X 10 to the 15th power kilometers moved since the explosion. So Zeta Oph has moved (3 X 10 to 15th km.) X (9.5 trillion km./light-year) = 316 light-years since the explosion. Since it's 460 l.y. away, it's moved about arctan(316/460) = 34 degrees across the sky, unless my math is wrong. Assuming the remnant's speed is the same or less, you'd have a circle of sky to search that's 68 degrees across. At least, it's within a thousand l.y. from us, which is pretty close.

Boomer12k, unless you have a very large telescope, I presume you did not "see" a consistent supernova remnant in a list of them. I'm curious to know what that list is.

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by BDanielMayfield » Sat Dec 29, 2012 6:15 pm

CMatisse wrote:Since it is moving so fast, does this mean it is in a different position every night?
No CMatisse. Since it’s so far away it, like almost all other stars takes an extremely long time (in human terms) to change apparent position relative to other stars. Wikipedia lists it’s proper motions as +15.26 and +24.79 mas/yr in RA and Dec respectively, with mas meaning milliarcseconds. A milliarcsecond is only 1/3600th of 1 degree, and 1 degree is only 1/180th of the distance across the entire sky.

Bruce

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by rr_carroll » Sat Dec 29, 2012 6:14 pm

Boomer12k wrote:I don't see a supernova remnant anywhere nearby. But maybe it is too faint now. I am thinking that if a larger companion exploded, then THIS would become the more massive, and the companion would now be dragged along with Zeta Oph. It would not have been "Flung" out of the system. It would just become the dominant mass of the system. The other could now be a small dwarf star, or even a black hole and traveling along too close to see maybe, or it just got blown away, and then Zeta Oph would just have "continued on its way". But I don't see an S.R. anywhere nearby, and I suppose it could be obscured by denser dust in another part of the nebulosity...
I was thinking along the same lines as Boomer12k - follow Zeta Oph's track backward and see if it passes near a supernova remnant. When I followed the links in the story, this seems to have been done for some runaway stars. But links to supernova info say that the supernova explosion can be assymetrical, so the SNR could recoil from the blast. I suppose it could gain a new velocity of unknown speed and direction. Still, it might be possible to find an SNR that's consistent with Zeta Oph's speed, distance and timing. I assume the companion SNR would have been mentioned if it were known.

Let's see, the last link in the story implies that Zeta Oph is about 4 million years old. At 24 km./sec. X 31 million sec/yr. X 4,000,000 yr. = about 3 X 10 to the 15th power kilometers moved since the explosion. So Zeta Oph has moved (3 X 10 to 15th km.) X (9.5 trillion km./light-year) = 316 light-years since the explosion. Since it's 460 l.y. away, it's moved about arctan(316/460) = 34 degrees across the sky, unless my math is wrong. Assuming the remnant's speed is the same or less, you'd have a circle of sky to search that's 68 degrees across. At least, it's within a thousand l.y. from us, which is pretty close.

Boomer12k, unless you have a very large telescope, I presume you did not "see" a consistent supernova remnant in a list of them. I'm curious to know what that list is.

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by CMatisse » Sat Dec 29, 2012 5:19 pm

Since it is moving so fast, does this mean it is in a different position every night?

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by neufer » Sat Dec 29, 2012 4:42 pm

Psnarf wrote:
You can find two of them on the full-sized image. They appear to be triangular in shape. Pretty hot to show up so bright in the infrared. Probably the same space monkeys that the ufo enthusiasts saw floating over south Phoenix/Tempe, AZ. a couple of years ago.

https://en.wikipedia.org/wiki/Black_triangle_%28UFO%29
  • Or possibly, it's Upsilon OPH :arrow:

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by Case » Sat Dec 29, 2012 3:31 pm

Image
A summer view on Zeta Ophiuchi from Tenerife latitude.

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by Psnarf » Sat Dec 29, 2012 3:11 pm

You can find two of them on the full-sized image. They appear to be triangular in shape. Pretty hot to show up so bright in the infrared. Probably the same space monkeys that the ufo enthusiasts saw floating over south Phoenix/Tempe, AZ. a couple of years ago.
https://en.wikipedia.org/wiki/Black_triangle_%28UFO%29

Re: APOD: Zeta Oph: Runaway Star (2012 Dec 29)

by neufer » Sat Dec 29, 2012 3:10 pm

Lordcat Darkstar wrote:
Shamanomaha wrote:
I notice a bright red dot in the star field just to the left of the shock wave. Any ideas what that could be?
If you zoom in you can see it has a halo around it. Kind of looks like planetary nebula to me.
I'm skeptical about it being a planetary nebula.

Nothing shows up at that spot in WISE: http://apod.nasa.gov/apod/ap110204.html

Top