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Cugel
2006-Aug-04, 12:56 AM
Message on Dutch Teletext today:

Astronomers have discovered two planets that do not orbit a star, but just each other. According to New Scientist magazine this means the planets did not originate from a star but were formed in another way.
Teletext also mentions that most planets are created around a star (this might be less obvious for Dutch TV viewers..) so this discovery is pretty amazing.

EdLee
2006-Aug-04, 01:48 AM
Whoa, sounds incredible to me.

Is it not possible that they formed from a star (as usual), but ended up orbiting each other somehow? (Like, say they were in orbit, had a collision, then drifted, then went into orbit around each other?)

Either way, very cool.

BigDon
2006-Aug-04, 02:14 AM
Ahh, how would you find such objects?

WaxRubiks
2006-Aug-04, 02:16 AM
here it is

http://www.space.com/scienceastronomy/060803_planemo_twins.html

Deadeye31
2006-Aug-04, 03:13 AM
well, if we don't call them planets, and they don't burn like Stars, then they'ed have to be super-massive asteroids.

BigDon
2006-Aug-04, 07:13 AM
Large Balls of Hydrogen, maybe?

tusenfem
2006-Aug-04, 08:28 AM
Well, it says they are 7 and 14 Jupiter mass Planemos.
I am totally for creation near a star and then through some process they got ejected as a pair. It sounds sooooo dramatic always in press releases "the theory of {..putinwhatyoulike...} needs to be totally revised because of this one observation."
I think scientist have to become more critical about the press releases that are send out.

WaxRubiks
2006-Aug-04, 08:33 AM
It said that the two bodies connected so delicately that it would be unlikely that they would have been created and then ejected and then come together to form this system, which makes sense. I don't see what is wrong with a system evolving like this.

tusenfem
2006-Aug-04, 12:00 PM
I read a little more on another site (see topic "line between planets and stars" and I must say that Frog march may be right. It is possible that from a small (sub)cloud these two have been created. Ejection might not be a good option.

ss002d6252
2006-Aug-04, 12:19 PM
I would guess that the best reason has them forming from a cloud that collapsed due to some sort of perturbation , possibly a supernova or close encounter with a star.

I would expect that theres probably a lot more of them out there that just haven't been spotted yet

WaxRubiks
2006-Aug-04, 12:22 PM
I suppose, one day they may form into a star if more matter goes their way.

Sticks
2006-Aug-04, 02:31 PM
How the BBC is reporting this (http://news.bbc.co.uk/1/hi/sci/tech/5241774.stm)

Fraser
2006-Aug-04, 02:58 PM
Astronomers have turned up plenty of extrasolar planets, but a newly discovered binary pair of planets is quite the find. The system consists of a 7-Jupiter mass planet and a 14-Jupiter mass planet... but no star. These planets - or "planemos" - just orbit each other. Their discovery challenges the current theory that planets are thought to form out of the disks of gas and dust that surround newborn stars.

Read the full blog entry (http://www.universetoday.com/2006/08/04/twin-planemos-discovered/)

Disinfo Agent
2006-Aug-04, 10:24 PM
Just the two of them and the starry sky... How romantic! :D ;) :clap:

blueshift
2006-Aug-05, 03:15 PM
Neat. Not only does that raise questions to the standard model but it kicks the plasma universe right in the butt.

VanderL
2006-Aug-05, 03:43 PM
Neat. Not only does that raise questions to the standard model but it kicks the plasma universe right in the butt.

Really? How so?

Cheers.

blueshift
2006-Aug-05, 04:28 PM
Really? How so?

Cheers.What took ya? When I put that up I bet myself that you would respond within 5 minutes despite being on the other side of the globe. There is an 18 minute lag between those posts which puts you either browsing elsewhere or out for coffee..Long time since we chatted. I'll get back to you but other matters need to be brought up, interrupting us a touch. One reason is here the other is in a private message.

Administrator, why is it that VanderL and I can get an exchange going here while over on the "off topic babbling" thread I cannot seem to get my post to take on the "favorite ancient civilization thread"? I keep getting that "page cannot be displayed" window no matter how many times I try to post and no matter how many different ways I try to do it. Something seems odd.

homo_cosmosicus
2006-Aug-06, 06:07 AM
The system consists of a 7-Jupiter mass planet and a 14-Jupiter mass planet... but no star.
These planets - or "planemos" - just orbit each other.

Now, if there is no star, then how did discovered those two planemos?
With no light from central star, how is it possible to discover object?

Obviously, they used visible light to take an "optical image taken with
ESO's 3.5-m New Technogoly Telescope at La Silla, Chile".

?

kenneth rodman
2006-Aug-06, 06:08 AM
how about this: they formed around a star billions of years ago, and another star passed close enough to cause them to spin off into interstellar space

WaxRubiks
2006-Aug-06, 06:55 AM
how about this: they formed around a star billions of years ago, and another star passed close enough to cause them to spin off into interstellar space

http://www.space.com/scienceastronomy/060803_planemo_twins.html


According to another theory, planemos are embryos ejected from nascent stellar nurseries. However, the two objects in Oph1622 are so far apart and so weakly bound to each other by gravity that they would not have survived such an ejection, the researchers say. Their connection is so tenuous, in fact, that a passing star or brown dwarf could permanently separate the two objects.

Kaptain K
2006-Aug-06, 07:18 AM
how about this: they formed around a star billions of years ago, and another star passed close enough to cause them to spin off into interstellar space
Nope, won't work. These objects are only a few million years old.

Speaking of which, at that age, at 14 Mj the larger object would still be fusing deuterium, making it a BD+planet system.

BigDon
2006-Aug-06, 07:52 AM
But if they were "ejectees" moving slow enough from different directions couldn't they have captured each other?

01101001
2006-Aug-06, 08:06 AM
Obviously, they used visible light to take an "optical image taken with
ESO's 3.5-m New Technogoly Telescope at La Silla, Chile".
ESO Image of planemo twins (http://www.eso.org/outreach/press-rel/pr-2006/phot-29-06.html#phot-29b-06)

http://www.eso.org/outreach/press-rel/pr-2006/images/phot-29b-06-icon.jpg (http://www.eso.org/outreach/press-rel/pr-2006/phot-29-06.html#phot-29b-06)

Near-infrared image of the system Oph 162225-240515AB, obtained with ISAAC on ESO's Very Large Telescope. North is up and East is to the left. The apparent separation is less than 2 arcseconds, corresponding to 242 times the distance between the Earth and the Sun (242 astronomical units) at the distance of the system, 400 light-years.
ESO Press Release (http://www.eso.org/outreach/press-rel/pr-2006/pr-29-06.html)

Aqualung
2006-Aug-06, 08:09 AM
This goes some way to prove my ideas right.

1. That there is not as much dark matter as everyone says there is.

2. There is a huge number of planemos in and around the galaxy which outnumber the visible stars by several times (by mass).

The solar system regularly interacts with them . In fact you could look at a stars oort cloud as a 'magic' buffer protecting the inner part of a system from passing planemos.

Eroica
2006-Aug-06, 09:07 AM
ToSeeked (http://www.bautforum.com/showthread.php?t=45235)

parallaxicality
2006-Aug-06, 10:32 AM
Is that binary planemo image in the public domain? I'd like to add it to my wiki article.

homo_cosmosicus
2006-Aug-06, 03:32 PM
Is that binary planemo image in the public domain? I'd like to add it to my wiki article.

Yes it is, click here for few image options, from small to very big, at the bottoom of this page:
http://www.eso.org/outreach/press-rel/pr-2006/phot-29-06.html#phot-29b-06

I would pick this image:

http://www.eso.org/outreach/press-rel/pr-2006/images/phot-29b-06-preview.jpg

homo_cosmosicus
2006-Aug-06, 03:35 PM
Near-infrared image of the system Oph 162225...



Of course, near infrared waves were used to make this image.

homo_cosmosicus
2006-Aug-06, 04:05 PM
I posted question on Questions forum, I would like to start playing with
near-infrared astronomy, to take pictures etc, if you know more about it
then please post here:
http://www.bautforum.com/showthread.php?t=45335

parallaxicality
2006-Aug-06, 04:32 PM
Well, the Wikipedians aren't letting it pass without absolute proof, so, in an act of despiration, I emailed one of the discoverers. Should be interesting whatever happens.

01101001
2006-Aug-06, 05:45 PM
Near-infrared image of the system Oph 162225...Of course, near infrared waves were used to make this image.
I strongly suspect that is why they employed the term "near-infrared" to describe the image.

Kaptain K
2006-Aug-07, 04:50 AM
But if they were "ejectees" moving slow enough from different directions couldn't they have captured each other?
No! A "two body" interaction cannot result in capture.

Tim Thompson
2006-Aug-07, 05:08 AM
These objects were discovered in an active star forming region, by astronomers at the European Southern Observatory. See the ESO press release: The 'Planemo' Twins (http://www.eso.org/outreach/press-rel/pr-2006/pr-29-06.html); "it is likely that these planemo twins formed together out of a contracting gas cloud that fragmented, like a miniature stellar binary, ...". Considering the masses involved, this makes sense to me. 7 Jupiter masses is surely "planetary", but 14 Jupiter masses is near the boundary between "planets" and "brown dwarfs". We already know there are free floating brown dwarfs, esepcially in clusters & active star forming regions. Interesting, but they don't seem all that mysterious to me.

kzb
2006-Aug-07, 11:48 AM
Aqualung wrote:


<<2. There is a huge number of planemos in and around the galaxy which outnumber the visible stars by several times (by mass).>>

I like this idea too, along with a large number of brown dwarves. If there were planemos and brown dwarf systems nearer to us than the nearest stars, it might help make interstellar travel that bit less impossible.

However, the MACHO detection research failed to find enough bodies to account for the mass of dark matter required. So it doesn't look as this concept is likely at present (unfortunately).

<<The solar system regularly interacts with them . In fact you could look at a stars oort cloud as a 'magic' buffer protecting the inner part of a system from passing planemos.>>

How is the Oort cloud going to "protect" us? It's actually the reverse situation, planemos drifting around out there at random would periodically disrupt the Oort cloud and send in comets to bombard us. The more planemos there are, the greater the frequency of comets coming in to hit us !

Argos
2006-Aug-07, 01:34 PM
Well, itīs seems that the word has taken root, in spite of all the complaints (http://www.bautforum.com/showthread.php?t=42384&highlight=planemos).

WaxRubiks
2006-Aug-07, 01:39 PM
could these planemos have moons I wonder.

hhEb09'1
2006-Aug-07, 01:45 PM
This goes some way to prove my ideas right.

1. That there is not as much dark matter as everyone says there is.

2. There is a huge number of planemos in and around the galaxy which outnumber the visible stars by several times (by mass).So, planemos are not dark matter?

Duane
2006-Aug-07, 03:19 PM
So, planemos are not dark matter?

It apopears not. Massive compact halo objects (MACHOs) like planemos, brown dwarfs and other dark and cool objects were looked for but not found. I don;t recall the details exactly, but it was something to do with looking for gravity lensing events that should have arisen fairly frequently, and didn't.

That's a big part of the reason that WIMPs (weakly interacting massive particles) became more favoured as a possible candidate for dark matter.

Sticks
2006-Aug-07, 03:23 PM
Planemo sounds like something you would get at your local coffee shop :)

parallaxicality
2006-Aug-07, 03:29 PM
Well, itīs seems that the word has taken root, in spite of all the complaints (http://www.bautforum.com/showthread.php?t=42384&highlight=planemos).

Humphs and says nothing.

Doodler
2006-Aug-07, 03:57 PM
Nope, won't work. These objects are only a few million years old.

Speaking of which, at that age, at 14 Mj the larger object would still be fusing deuterium, making it a BD+planet system.

Wouldn't the presence deuterium fusion show a substantial difference in its IR spectra? And given the haziness of the boundary, could a less dense 14 Mj object not be fusing deuterium?

Ilya
2006-Aug-07, 04:34 PM
Nope, won't work. These objects are only a few million years old.

Speaking of which, at that age, at 14 Mj the larger object would still be fusing deuterium, making it a BD+planet system.
What is BD+?

Doodler
2006-Aug-07, 08:19 PM
What is BD+?

"Brown Dwarf Plus" as in Brown Dwarf plus Planet.

Tim Thompson
2006-Aug-07, 08:48 PM
Wouldn't the presence deuterium fusion show a substantial difference in its IR spectra?
No, the spectrum will be dominated by absorption in the atmosphere. But the presence of deuterium fusion will make the temperature relatively high, and that can be determined from the IR spectrum. There are no IR spectra for these objects as yet, but the discoverers are proposing to do that. With IR spectra giving a temperature, knowing the distance and age, a more precise mass can be derived for both objects.


And given the haziness of the boundary, could a less dense 14 Mj object not be fusing deuterium?
It's the total mass that fixes the central temperature, which determines whether or not there is deuterium fusion. Compression comes from the total weight above the core, which comes from the total mass, regardless of density.

hhEb09'1
2006-Aug-07, 10:25 PM
It apopears not. Massive compact halo objects (MACHOs) like planemos, brown dwarfs and other dark and cool objects were looked for but not found. I don;t recall the details exactly, but it was something to do with looking for gravity lensing events that should have arisen fairly frequently, and didn't. So, aqualung's theory has been tested, and it failed?

BigDon
2006-Aug-08, 12:13 AM
No! A "two body" interaction cannot result in capture.


Why is that?

I'm not challenging your statement, I'm just curious. I hadn't heard that one before.

Ilya
2006-Aug-08, 02:09 AM
If two bodies are not already orbiting each other, they will approach at parabolic or hyperbolic trajectories, will reach maximum velocity at the closests approach, then will recede along the same parabolas or hyperbolas. Locations, velocities and accelerations of each body after the closest approach exactly mirrors those before the approach -- in effect, the entire event is like a movie run once, then run backward and in the mirror. They fell toward each other from infinity and will recede into infinity.

A capture always requires some force other than two-body gravitational interaction -- something has to steal some kinetic energy from one or both participants. Most likely it is gravity of a third body, but can be collision with the third body, or even aerobraking (if one body is large and has thick atmosphere, while the other is small).

BigDon
2006-Aug-08, 02:45 AM
Ah, thanks Ilya.

So if one or both were travelling through thick nebula, could that have slowed one down? Something thick like a Bok globule? A star forming region by definition has got to be pretty dense. (Not argueing, just supposing)

I have nothing against the cloud spliting in two or more ala multiply star systems method. Ohh wait, what if there was a third, more massive body that was displaced by another passing star? Could that has left them dancing with each other? If they were at the far end of their orbits when it happened? These were found in a steller nursery after all. Got to be alot of traffic we don't get around here. (Thank God)

Kaptain K
2006-Aug-08, 05:36 AM
A star forming region by definition has got to be pretty dense.
Density is relative. While star forming regions are "dense" by interstellar standards, they are still a [darn] fine vacuum.

kzb
2006-Aug-08, 12:23 PM
<<So, aqualung's theory has been tested, and it failed>>

Basically, yes. Apparently, not anywhere near enough objects, down to one millionth sun mass, were found.

Mike525
2006-Aug-11, 05:08 PM
Does anyone have source info regarding the MACHO results and the "measuring tolerances" they were using? Any good links? Maybe the lens effect of these very low mass objects are below this (as kzb mentions as one millionth sun mass). Earth mass objects are less than one millionth the suns I think.

How about the distorting effect of interstellar dust to these measurements.

I don't think the mass is several times as large as the total # of stars (as Aqualung thinks) but I do think the # of substellars/planemos are several times as numerous.

Would like to check out more MACHO details so please drop a post anyone.
Thanks.

Mike

ToSeek
2006-Aug-11, 06:28 PM
ToSeeked (http://www.bautforum.com/showthread.php?t=45235)

Threads merged.

selden
2006-Aug-11, 08:38 PM
Mike,

Searching Arxiv for papers coauthored by Alcock with the word MACHO in the subject will keep you busy for a while :) Most of the papers include a description of their search parameters.

http://archiv.org/find

Mike525
2006-Aug-13, 03:48 PM
Thanks selden,

Actually from arxiv.org I found the project homepage.

http://wwwmacho.mcmaster.ca/Project/Overview/status.html

I am now clear on exactly what the "halo" term is referring with the overview saying:

"Our primary aim is to test the hypothesis that a significant fraction of the dark matter in the halo of the Milky Way is made up of objects like brown dwarfs or planets: these objects have come to be known as MACHOs, for MAssive Compact Halo Objects."

So they are just testing the outer halo region and so interstellar regions in the galactic rim are still fertile ground for BDs and planemos. And as I mentined they still can be several times as numerous as stars while only accounting for a fraction of the mass of dark matter.

Also in regards to halo region - the numerous globular clusters, in some theoretical models (which consider GC stars as relatively young based on different star formation theories), are considered young having been formed in intergalactic regions and then gravitating to an existing galaxy and eventually being swallowed and added to the galaxy. So within the clusters there may be many young substellar objects.

So the space between GC's should be relatively vacant which is what they seem to indicate.

publiusr
2006-Aug-25, 06:58 PM
I wonder just what might be between us and Proxima Centauri that we haven't seen.

jkmccrann
2006-Aug-29, 09:44 AM
Astronomers have turned up plenty of extrasolar planets, but a newly discovered binary pair of planets is quite the find. The system consists of a 7-Jupiter mass planet and a 14-Jupiter mass planet... but no star. These planets - or "planemos" - just orbit each other. Their discovery challenges the current theory that planets are thought to form out of the disks of gas and dust that surround newborn stars.

Read the full blog entry (http://www.universetoday.com/2006/08/04/twin-planemos-discovered/)

Does it really challenge the current theory? As has been mentioned, I thought the upper-limit for a planet was understood to be at about 13 Jupiter masses.

Doesn't an object, that is not a star, at 14 Jupiter masses suggest a failed star - rather than a challenge to current thought?

Who says that every region of accreting dust must necessarily coalesce into a star, wouldn't it be more likely to expect some sort of continuum of results of this accretionary process?

If this discovery challenges current theories, it seems to be suggesting to me that with current theories there is no continuum past a certain point - it simply drops off to nothing.



Their discovery challenges the current theory that planets are thought to form out of the disks of gas and dust that surround newborn stars.


As I would understand it, not only would planets form out of these disks of gas and dust - but so would the star that ends up at the centre! Surely a star just doesn't appear out of nowhere and suddenly have a surrounding disk of dust and gas that slowly accretes into planets.

Is there really nothing in the current theory that address what happens with a region of dust and gas when there is not enough mass there to form into a hydrogen/helium fusing star? Surely not - I don't see the challenge these guys present - can someone explain what exactly this challenge is?

jkmccrann
2006-Aug-29, 09:49 AM
So, planemos are not dark matter?

But isn't dark matter a different type of matter? Planemos that don't orbit stars - of which there are no doubt countless trillions in our galaxy surely have nothing to do with dark matter.

I presume that in any calculation of the mass of the galaxy, and the Universe, that the mass of free floating objects unattached to stars is taken into account - but I have no idea whether the value of that mass is significant, insignificant, negligible or completly negligble.

At a guess, I'd guess somewhere between insignificant and negligible - but it would have to be taken into account in any theory of the mass of the galaxy or universe - but it also is surely nothing to do with dark matter.

kzb
2006-Aug-29, 12:03 PM
<<Does anyone have source info regarding the MACHO results and the "measuring tolerances" they were using? Any good links? Maybe the lens effect of these very low mass objects are below this (as kzb mentions as one millionth sun mass). Earth mass objects are less than one millionth the suns I think.>>

I've been trying to find out more detail myself. Some ideas that struck me straight away:

The scientists concerned knew they'd have to stand up and defend the the microlensing events they detected. That could mean a great many possible events were discarded, simply because they were not 100% sure.

Inevitably, given the huge amount of observations, it had to be automated. Now, forgive me, but computer software is usually c**p. I wonder how well validated it was.

Personally I think people have given up on baryonic dark matter a bit too quickly.