New evidence that all stars are born in pairs

June 14, 2017 by Robert Sanders, University of California - Berkeley
New evidence that all stars are born in pairs
Radio image of a very young binary star system, less than about 1 million years old, that formed within a dense core (oval outline) in the Perseus molecular cloud. All stars likely form as binaries within dense cores. Credit: SCUBA-2 survey image by Sarah Sadavoy, CfA

Did our sun have a twin when it was born 4.5 billion years ago?

Almost certainly yes—though not an identical twin. And so did every other sunlike star in the universe, according to a new analysis by a theoretical physicist from UC Berkeley and a radio astronomer from the Smithsonian Astrophysical Observatory at Harvard University.

Many have companions, including our nearest neighbor, Alpha Centauri, a triplet system. Astronomers have long sought an explanation. Are binary and triplet star systems born that way? Did one star capture another? Do binary stars sometimes split up and become single stars?

Astronomers have even searched for a companion to our sun, a star dubbed Nemesis because it was supposed to have kicked an asteroid into Earth's orbit that collided with our planet and exterminated the dinosaurs. It has never been found.

The new assertion is based on a radio survey of a giant filled with recently formed stars in the constellation Perseus, and a mathematical model that can explain the Perseus observations only if all sunlike stars are born with a companion.

"We are saying, yes, there probably was a Nemesis, a long time ago," said co-author Steven Stahler, a UC Berkeley research astronomer.

"We ran a series of statistical models to see if we could account for the relative populations of young single stars and binaries of all separations in the Perseus molecular cloud, and the only model that could reproduce the data was one in which all stars form initially as wide binaries. These systems then either shrink or break apart within a million years."

A radio image of a triple star system forming within a dusty disk in the Perseus molecular cloud obtained by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. Credit: Bill Saxton, ALMA (ESO/NAOJ/NRAO), NRAO/AUI/NSF

In this study, "wide" means that the two stars are separated by more than 500 astronomical units, or AU, where one astronomical unit is the average distance between the sun and Earth (93 million miles). A wide binary companion to our sun would have been 17 times farther from the sun than its most distant planet today, Neptune.

Based on this model, the sun's sibling most likely escaped and mixed with all the other stars in our region of the Milky Way galaxy, never to be seen again.

"The idea that many stars form with a companion has been suggested before, but the question is: how many?" said first author Sarah Sadavoy, a NASA Hubble fellow at the Smithsonian Astrophysical Observatory. "Based on our simple model, we say that nearly all stars form with a companion. The Perseus cloud is generally considered a typical low-mass star-forming region, but our model needs to be checked in other clouds."

The idea that all stars are born in a litter has implications beyond , including the very origins of galaxies, Stahler said.

Stahler and Sadavoy posted their findings in April on the arXiv server. Their paper has been accepted for publication in the Monthly Notices of the Royal Astronomical Society.

Stars birthed in 'dense cores'

Astronomers have speculated about the origins of binary and multiple star systems for hundreds of years, and in recent years have created computer simulations of collapsing masses of gas to understand how they condense under gravity into stars. They have also simulated the interaction of many young stars recently freed from their gas clouds. Several years ago, one such computer simulation by Pavel Kroupa of the University of Bonn led him to conclude that all stars are born as binaries.

This infrared image from the Hubble Space Telescope contains a bright, fan-shaped object (lower right quadrant) thought to be a binary star that emits light pulses as the two stars interact. The primitive binary system is located in the IC 348 region of the Perseus molecular cloud and was included in the study by the Berkeley/Harvard team. Credit: NASA, ESA and J. Muzerolle, STScI

Yet direct evidence from observations has been scarce. As astronomers look at younger and younger stars, they find a greater proportion of binaries, but why is still a mystery.

"The key here is that no one looked before in a systematic way at the relation of real young stars to the clouds that spawn them," Stahler said. "Our work is a step forward in understanding both how binaries form and also the role that binaries play in early stellar evolution. We now believe that most stars, which are quite similar to our own sun, form as binaries. I think we have the strongest evidence to date for such an assertion."

According to Stahler, astronomers have known for several decades that stars are born inside egg-shaped cocoons called dense cores, which are sprinkled throughout immense clouds of cold, molecular hydrogen that are the nurseries for young stars. Through an optical telescope, these clouds look like holes in the starry sky, because the dust accompanying the gas blocks light from both the stars forming inside and the stars behind. The clouds can, however, be probed by radio telescopes, since the cold dust grains in them emit at these radio wavelengths, and radio waves are not blocked by the dust.

The Perseus molecular cloud is one such stellar nursery, about 600 light-years from Earth and about 50 light-years long. Last year, a team of astronomers completed a survey that used the Very Large Array, a collection of radio dishes in New Mexico, to look at star formation inside the cloud. Called VANDAM, it was the first complete survey of all young stars in a molecular cloud, that is, stars less than about 4 million years old, including both single and mulitple stars down to separations of about 15 astronomical units. This captured all multiple stars with a separation of more than about the radius of Uranus' orbit—19 AU—in our solar system.

Stahler heard about the survey after approaching Sadavoy, a member of the VANDAM team, and asking for her help in observing young stars inside dense cores. The VANDAM survey produced a census of all Class 0 stars – those less than about 500,000 years old – and Class I stars – those between about 500,000 and 1 million years old. Both types of stars are so young that they are not yet burning hydrogen to produce energy.

Sadavoy took the results from VANDAM and combined them with additional observations that reveal the egg-shaped cocoons around the young stars. These additional observations come from the Gould Belt Survey with SCUBA-2 on the James Clerk Maxwell Telescope in Hawaii. By combining these two data sets, Sadavoy was able to produce a robust census of the binary and single-star populations in Perseus, turning up 55 young stars in 24 multiple-star systems, all but five of them binary, and 45 single-star systems.

Using these data, Sadavoy and Stahler discovered that all of the widely separated binary systems—those with stars separated by more than 500 AU—were very young systems, containing two Class 0 stars. These systems also tended to be aligned with the long axis of the egg-shaped dense core. The slightly older Class I binary stars were closer together, many separated by about 200 AU, and showed no tendency to align along the egg's axis.

A dark molecular cloud, Barnard 68, is filled with gas and dust that block the light from stars forming inside as well as stars and galaxies located behind it. These and other stellar nurseries, like the Perseus molecular cloud, can only be probed by radio waves. Credit: FORS Team, 8.2-meter VLT Antu, ESO

"This has not been seen before or tested, and is super interesting," Sadavoy said. "We don't yet know quite what it means, but it isn't random and must say something about the way wide binaries form."

Egg-shaped cores collapse into two centers

Stahler and Sadavoy mathematically modeled various scenarios to explain this distribution of stars, assuming typical formation, breakup and orbital shrinking times. They concluded that the only way to explain the observations is to assume that all stars of masses around that of the sun start off as wide Class 0 binaries in egg-shaped dense cores, after which some 60 percent split up over time. The rest shrink to form tight binaries.

"As the egg contracts, the densest part of the egg will be toward the middle, and that forms two concentrations of density along the middle axis," he said. "These centers of higher density at some point collapse in on themselves because of their self-gravity to form Class 0 stars."

"Within our picture, single low-mass, sunlike stars are not primordial," Stahler added. "They are the result of the breakup of . "

Their theory implies that each dense core, which typically comprises a few solar masses, converts twice as much material into stars as was previously thought.

Stahler said that he has been asking radio astronomers to compare dense cores with their embedded young stars for more than 20 years, in order to test theories of binary star formation. The new data and model are a start, he says, but more work needs to be done to understand the physics behind the rule.

Such studies may come along soon, because the capabilities of a now-upgraded VLA and the ALMA telescope in Chile, plus the SCUBA-2 survey in Hawaii, "are finally giving us the data and statistics we need. This is going to change our understanding of dense cores and the embedded stars within them," Sadavoy said.

Explore further: No close partner for young, massive stars in Omega Nebula

More information: Embedded Binaries and Their Dense Cores. arxiv.org/abs/1705.00049

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40 comments

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Phil DePayne
3 / 5 (2) Jun 14, 2017
Great, I think this can give support to tidal theories of planet formation!
Scroofinator
1 / 5 (3) Jun 14, 2017
a star dubbed Nemesis

Which is now a black hole which we have found evidence for, aka the hunt for "planet 9"
Shootist
3 / 5 (2) Jun 14, 2017
All is a big word to describe a chaotic system. 'nuff said
richk
1.8 / 5 (4) Jun 14, 2017
what's/the/idea?collapsing/cloud/produces/separate/eddies?Just/two?Not/intuitively/obvious/to/me.Help?
Nik_2213
5 / 5 (1) Jun 14, 2017
Given that Jupiter's formation was recently constrained to 'very soon' after the Sun's self-build went large, does this mean Jupiter is technically the ultimate 'Little Ender' ?? Easy to say in cases of 'Brown Dwarfs', but Jupiter didn't make that grade, either...
EmceeSquared
3 / 5 (2) Jun 14, 2017
Nik_2213:
Jupiter is technically the ultimate 'Little Ender' ??

"Evidence that Jupiter is the oldest planet in the solar system" Jun 13, 2017 12
https://phys.org/...lar.html
someone11235813
5 / 5 (1) Jun 15, 2017
Very interesting finding and explains why 80 per cent of stars are in a binary system. For some reason those who want to claim that life and even intelligent life is abundant in the Galaxy never seem to take this into account. Our Sun is always described as a typical star but if it's in the clear minority of non binary stars then it cannot be typical in the sense that it is used, when talking about life getting under way.
yaridanjo
1 / 5 (1) Jun 15, 2017
Ultra tiny brown dwarf, Mass, Orbital parameters here:

http://www.barry....led.html
SUMMARY: VULCAN'S NEW ORBITAL PARAMETERS

Aph./Peri 447.6.134.8 AU. Three orbital parameters verified. Its orbital inclination is the same as one of the two proposed for Planet Nine. we called it Vulcan when we discovered it in 2002.
yaridanjo
1 / 5 (1) Jun 15, 2017
Ultra tiny brown dwarf, Mass, Orbital parameters here:

http://www.barry....led.html
VULCAN REVEALED
A Dangerous New Jovian Sized Body In Our Solar System

Its orbital inclination is the same as one of the two proposed for Planet Nine
OsmanArslan
1.7 / 5 (6) Jun 15, 2017
'And all things We have created by pairs, that haply ye may reflect.' Qur'an Verse (51:49)
zenochron
5 / 5 (1) Jun 15, 2017
I wonder if jupiter is the sibling mass.
Origin314
1 / 5 (2) Jun 15, 2017
Perhaps Pluto was the tiny Nemesis?
Anda
not rated yet Jun 15, 2017
"New evidence that all stars are born in pairs"
Such an absolute and simplistic statement cannot be true.

"The new assertion is based on a radio survey of a giant molecular cloud filled with recently formed stars in the constellation Perseus, and a mathematical model that can explain the Perseus observations only if all sunlike stars are born with a companion."

Keep on working...

EmceeSquared
4 / 5 (4) Jun 15, 2017
OsmanArslan:
'And all things We have created by pairs, that haply ye may reflect.' Qur'an Verse (51:49)


The idea of duality of all existence goes back to at latest Classical Egypt:
http://escholarsh...b#page-3
Pearlman_CTA
1 / 5 (5) Jun 15, 2017
like Cain and Ebel (had twin sisters, Cain was a triplet),
also the sons of Jacob (himself a twin as were Rachel and Leah) had twin sisters according to at least some.
according to those who hold BaKol is a daughter of Abraham and Sarah, could she be a twin of Yitzchak?
Pearlman_CTA
1 / 5 (4) Jun 15, 2017
The relatively high number of double stars has long been a tell of ID and also YeC friendly amongst creation science astro-physicists.
that many/most/all were born that way is very SPIRAL friendly as per SPIRAL the proto-stars formed as early as creation week day one.
in the case of identical twins humans think of our analogy of a single cell dividing into two and twins from those two.
now in the case of stars think of the initial singularity.
now think of the RCCF-SPIRAL references in Talmud and RambaN of that splitting into two, the inner and the outer. the outer includes the stars w/ the exception of the Sun.
now think of that outer continuing to divide x times - to be continued
Pearlman_CTA
1 / 5 (4) Jun 15, 2017
now think of that outer with each cell (star) continuing to divide x times.
(just like not each snow flake is alike, and not each oak tree even if developed from acorns from the same parent tree, each twin star need not be identical.)
Allow for occasional triplet, quadruplet, or single.. like chestnuts :).
Nearest twin would most often be closer to each other, than cousins.. thus groups of proto galaxy clusters could have also predated the cosmic inflation cosmic expansion event as hypothesized in SPIRAL ..
reference: SPIRAL cosmological redshift hypothesis and cosmology model
EmceeSquared
4 / 5 (4) Jun 15, 2017
Pearlman_CTA:
like Cain and Ebel (had twin sisters, Cain was a triplet)


What is this superstition doing in a science discussion? It's gibberish anyway: Triplets aren't born in pairs.
Pearlman_CTA
1 / 5 (3) Jun 15, 2017
reference link herein for prior two posts on topic of double stars:
SPIRAL vs SCM infographic: www.researchgate....17415683
Pearlman_CTA
1 / 5 (4) Jun 15, 2017
Hi ES
One common designer/ creator. Is the most basic foundation for understanding science in context.
often in science we use analogies between two distinct natural phenomena observations.
you may not recognize it as science as you have never been taught/considered it (SPIRAL and RCCF) fairly
With stars while most may be twins, yet how do you preclude any triplets..?
also a triplet could be a pair plus a single
the single could have started as part of a pair..
EmceeSquared
4 / 5 (4) Jun 15, 2017
Pearlman_CTA:
One common designer/ creator. Is the most basic foundation for understanding science in context.


No it is not science. It is superstition and/or gibberish, not science. This site is for posts about science.

There are many sites where you can post that kind of non-science where people might actually be interested in it. Post there instead.
EmceeSquared
3.7 / 5 (3) Jun 15, 2017
Anda:
"New evidence that all stars are born in pairs"
Such an absolute and simplistic statement cannot be true.


Of course it could be true. "All triangles have 180 degrees", "E=mc^2" can't be true because they're "absolute and simplistic"?
EmceeSquared
3.7 / 5 (3) Jun 15, 2017
Pearlman_CTA:
now think of that outer with each cell (star) continuing to divide x times.


Stars don't divide. Except maybe in some superstition (or drugged delusion) that doesn't belong on a science site. Post elsewhere.
Nik_2213
5 / 5 (3) Jun 15, 2017
Care: "All triangles have 180 degrees" only applies to plane geometry...
FredJose
1 / 5 (2) Jun 15, 2017
Yet direct evidence from observations has been scarce. As astronomers look at younger and younger stars, they find a greater proportion of binaries, but why is still a mystery.

And no wonder - the observations are so scarce as to be non-existent. To date no one has recorded or discovered the event of a star bursting on the scene from a cloud of gas. And had such event confirmed as the "birth" of a new star.
Drjsa_oba
5 / 5 (6) Jun 15, 2017
@FredJose.

My initial reaction to your post was to call you a dickhead. But that may be misconstrued as some kind of insult. I do not believe in insulting people on the internet.

Therefore I will say you comment is asinine. I could explain why, but that would probably be wasted effort.
EmceeSquared
4 / 5 (4) Jun 16, 2017
Lex Talonis:
OK, so what has happened to all the old evidence


With all due respect to Drjsa_oba, you're a dickhead.
someone11235813
not rated yet Jun 18, 2017
Of course it could be true. "All triangles have 180 degrees", "E=mc^2" can't be true because they're "absolute and simplistic"?


Funny thing is that the ancient Greeks worshiped mathematics because it was demonstrably true and this lasted for two thousand years until non Euclidean geometry was discovered and showed that it wasn't really as absolute as once believed. Draw a triangle on the Earth whose points are 1. The north pole and 2. at 0 degrees longitude and 3. at 90 degrees longitude and you have a triangle with 3 right angles!
EmceeSquared
3 / 5 (2) Jun 18, 2017
someone11235813:
Of course it could be true. "All triangles have 180 degrees", "E=mc^2" can't be true because they're "absolute and simplistic"?


Funny thing is


Funny thing about "true" is that there's always going to be margins of error in human knowledge: Godel's Incompleteness Theorem explains that guarantee. Einstein's "E=mc^2" was part of the revision to Newton's "F = G((m1*m2)/r^2)". Yet each formulation is both simple and true enough to use for all contemporary intents and purposes. Likewise non-Euclidean geometry.

To reject an accurate, if never perfectly precise, description as "cannot be true" because it's absolute and "simplistic" is a cruelly ironic absolute and actually "simplistic" (not just "simple") fallacy.
someone11235813
not rated yet Jun 18, 2017
@EmceeSquared, mathematics wasn't like that. Mathematics was believed to be absolutely true by definition. Like 1 plus 1 is true and always will be. We do not expect that quantum physics will not be subsumed by another better theory in 100 years just as general relativity subsumed Newton but no one saw non Euclidean geometry coming. With regards to true, I define it as 'that which *cannot* be denied. And the only thing that cannot be denied is one's own knowledge that 'I am', I exist. What that 'I' is is a matter for debate which is a separate topic.
3Travis
3 / 5 (1) Jun 19, 2017
Could this duplicity of born stars as twins imply in any way the existence of parallel universes?
Whydening Gyre
5 / 5 (2) Jun 19, 2017
Could this duplicity of born stars as twins imply in any way the existence of parallel universes?

No. It implies (primarily) gravitational mechanics.
Whydening Gyre
5 / 5 (1) Jun 19, 2017
Of course it could be true. "All triangles have 180 degrees", "E=mc^2" can't be true because they're "absolute and simplistic"?


Funny thing is that the ancient Greeks worshiped mathematics because it was demonstrably true and this lasted for two thousand years until non Euclidean geometry was discovered and showed that it wasn't really as absolute as once believed. Draw a triangle on the Earth whose points are 1. The north pole and 2. at 0 degrees longitude and 3. at 90 degrees longitude and you have a triangle with 3 right angles!

Since the N. Pole is AT 90 degrees long., all you have is a straight line. Better re-think your non-Euclidean...

Dingbone
Jun 19, 2017
This comment has been removed by a moderator.
EmceeSquared
1 / 5 (1) Jun 19, 2017
someone11235813:
Like 1 plus 1 is true and always will be.


1 + 1 = 10 in binary. Rejecting a scientific or mathematical statement as "cannot be true" because it's "absolute and simplistic" (or rather "simple", because "simplistic" is of course a tautological reason for rejection) is fallacious.
OceanDeep
3 / 5 (1) Jun 19, 2017
Cool idea. But is it possible that what was supposed to be the Sun's twin got dispersed and resulted in Jupiter, Saturn, Neptune, and Uranus?
mansoorsa
not rated yet Jun 21, 2017
"all stars are born in pair":
The current census of cosmos tells us that there are more red dwarfs (earlier companions of much larger brighter stars). This means that most of the larger and brighter companions are long gone (burning faster than comparing red dwarfs). Otherwise census should have shown almost equal number of red dwarf and companion larger brighter stars. Cosmos must have been much brighter times when larger and brighter companions of these red dwarfs were around

Well this is yet another hypothesis!
someone11235813
not rated yet Jun 21, 2017
e=mc^2 "1 + 1 = 10 in binary."

And your point is what? that 10 in binary is not 2? Are you now going to say 1 does not equal 1 if the second 1 was written in a different colour?
EmceeSquared
1 / 5 (1) Jun 26, 2017
someone11235813:
And your point is what?


You posted "1 plus 1 is true", so I was just having some fun with your mistake in the binary that is used to represent "true" (and "false"). However simple the equations, they're meaningless without the context in which they're evaluated, which is hidden complexity - allowing simple equations.

Simplicity is in the eye of the beholder, and not a criterion for whether a mathematical statement is correct. I already pointed out E=mc^2 , which is both simple and absolute despite your simplistic and absolute statement that it cannot be because simplistic and absolute mathematical statements cannot be true.

Try to keep up with your own assertions. At least have a sense of humor about it when you don't.
wardrho9
not rated yet Jul 14, 2017
All is a big word to describe a chaotic system

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