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Questions tagged [binary-star]

Questions regarding a pair of stars that are gravitationally bound and orbit around their barycenter.

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Is Sun a part of a binary system?

Does our Sun have a counterpart, i.e., is it a part of a binary-system? If so, how does the other star look like and where is it?
stp30's user avatar
  • 575
25 votes
4 answers
4k views

Are there any double stars that I can actually see orbit each other?

If I had a nice amateur telescope†, are there any multiple star systems that I could observe over a few years or a few decades and actually see the movement of one or both of them over time? My short ...
uhoh's user avatar
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17 votes
2 answers
745 views

What are the current observational constraints on the existence of Nemesis?

Nemesis is a hypothetical companion to the Sun on a very eccentric, long-period orbit. The star supposedly returns every few tens of millions years, driving comets into the inner solar system and ...
Guillochon's user avatar
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6 votes
3 answers
255 views

What is the spectral reflectance of starlight in a close binary?

Ignore the Blender Monkey! (from here) In a close-orbiting binary pair, a small but significant fraction of the light from each star falls upon the other, and the result has to be carefully modeled ...
uhoh's user avatar
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13 votes
1 answer
3k views

Why can't our Sun be a binary with Jupiter as a T or Y dwarf?

I just learned about Brown Dwarfs, they are "failed" stars, they narrowly missed the stellar mass mark. I learned that Y Dwarfs have temperature as low as 80 Fahrenheit (The first one found by WISE ...
fahadash's user avatar
  • 501
18 votes
2 answers
907 views

How many stars can stay close to each other without collapsing?

Is it possible for two stars to exist close to each other? "Close" is relative; let's assume that two stars are close to each other if they are at the center of the same solar system. It's ...
Zoltán Schmidt's user avatar
7 votes
2 answers
651 views

What's the name for [the other kind of planet] in a binary star system?

This XKCD what-if talks about rainbows on planets in a binary star system. It points out that there are two types: circumbinary planets, where the planet orbits far from and around both stars [the ...
ThePopMachine's user avatar
1 vote
2 answers
355 views

Binary pairings that haven't been discovered yet?

Question: Are there any kinds of binary pairings that haven't been discovered yet? Any that are particularly significant, or that might shed some light on binary stellar evolution or theories of ...
uhoh's user avatar
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30 votes
1 answer
9k views

How far apart are stars in a binary system?

I'm wondering how far apart from one another the stars are in binary systems. What is the distribution of the separation between binary stars? Are most of the binary stars very far apart like Sirius (...
usernumber's user avatar
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14 votes
2 answers
2k views

How are binary star systems created?

I don't know how common it is for a system to have two stars (or perhaps even more) but how do they arise? Is that due to the stellar accretion disc, or the composition of the stellar nebula? Or are ...
Marijn 's user avatar
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13 votes
4 answers
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Will Sirius B start accreting from A and become a supernova type Ia?

Sirius B is a massive white dwarf of 1 Solar mass, orbiting at about 25 AU distance from the 2 Solar mass Sirius A. As it evolves and expands, will the A star start shedding matter to the white dwarf, ...
LocalFluff's user avatar
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12 votes
1 answer
2k views

Orbits in a binary star system

I know of three sets of stable orbits in a binary star system: orbiting closely around star A, orbiting closely around star B, or orbiting distantly around both stars (and their mutual center of ...
Mark's user avatar
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10 votes
1 answer
194 views

V471 Tauri's circumbinary brown dwarf non-observation; Applegate, or over-restrictive assumptions?

tl;dr Has the brown dwarf observation been disproven? I have just started reading about the interesting object V471 Tauri. The first two sentences of the introduction to The V471 Tauri System: A ...
uhoh's user avatar
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10 votes
2 answers
4k views

Multiple Star-system percentages

What are the percentages of systems that have x number of stars in them? What I have found thus far is something like: Single Star Sytems = 69% Double Star Systems = ~10% Triple Star Systems = <...
Durakken's user avatar
  • 397
9 votes
3 answers
3k views

Binaries consisting of a black hole and a non-black hole?

Are there any known binary systems in which one member is a black hole and the other is not a black hole (main sequence star, giant, neutron star, white dwarf, whatever)? Googling seems to turn up ...
user avatar
7 votes
1 answer
268 views

Is it possible for two stars to be in a horseshoe orbit around a much larger star?

I was reading about how Saturn has two moons, Janus and Epimetheus, that swap orbits once every four years. Could something like this happen on a much larger scale, but with stars instead of a planet ...
Gliese's user avatar
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3 votes
1 answer
269 views

Do planets form around lone stars, multiple stars, or both? Do we know this yet?

Since about 1990 astronomers been able to detect planets around other stars, using a couple different techniques, which is amazing. By this point, do we know whether planets form only around single ...
Fattie's user avatar
  • 946
3 votes
2 answers
1k views

Is the angular resolution of a telescope irrespective of used eye-piece?

Suppose a telescope has aperture $D = 20$ cm. The angular resolution of such telescope, according to the Rayleigh criterion (if I have understood it correctly), is given by $$\theta = 1.22\cdot\frac{...
mmh's user avatar
  • 394
3 votes
2 answers
911 views

Filling the Roche Lobe

For mass transfer in a binary system, one star must fill its Roche lobe. What determines whether a star in a binary system will fill its Roche Lobe? How will I calculate it? I can't find any ...
Arnab Chowdhury's user avatar
2 votes
1 answer
574 views

Orbital speeds of Components of Binary System

How does one calculate the orbital speed s of the members of a binary system? Iirc, the average separation of Alpha Centauri A and B is 23 AU, but the orbit is highly elliptical, so that the ...
Mike Stone's user avatar
2 votes
1 answer
184 views

Why do they think that WDJ0551+4135 is "snowman shaped" i.e. a contact binary?

The BBC's Huge 'space snowman' is two merging stars says Researchers have discovered a huge snowman-shaped star with an atmospheric composition never seen before. It is more massive than our Sun but ...
uhoh's user avatar
  • 30.7k
1 vote
0 answers
241 views

Relationships between G magnitude, Johnson V magnitude, and spectral type of stars?

I'm simulating a population of binary stars for a summer research project. I'm adding uncertainties to my simulated observables such as angular position and radial (line of sight) velocity. I'm using ...
Sofia Splawska's user avatar
1 vote
1 answer
192 views

Is the smaller companion of Pulsar J0453+1559 still the smallest known neutron star? Was it further confirmed to be a NS after Martinez et al. (2015)?

@ProfRob's Physics SE answer to What is the theoretical lower mass limit for a gravitationally stable neutron star? was linked just now in their answer to Can a neutron star ever be less than about 1....
uhoh's user avatar
  • 30.7k
1 vote
1 answer
974 views

What would shadows look like on a planet with two suns?

On planet Tatooine which has two (main-sequence I guess) suns people still have one shadow only. Tatooine's suns seem quite close to each other, so it may actually be the case that the two shadows are ...
John's user avatar
  • 1,538
1 vote
0 answers
133 views

The black hole binary that was detected by advanced LIGO - how do such hypergiant binaries form?

With today's announcement of the historic detection of gravitational waves from the merger of 36 solar mass and 29 solar mass black holes 1.3 billion light years away, one can not help but wonder how ...
dualredlaugh's user avatar
1 vote
1 answer
127 views

State vectors of "interesting" multiple stars

I'd like to show a demonstration of Runge Kutta integration of real systems using examples of interesting multiple stars, where "interesting" means you can see through a small telescope that they are ...
uhoh's user avatar
  • 30.7k
0 votes
0 answers
167 views

2-body orbits expanding in nbody simulation?

Recently, I designed an n-body engine and tested it with a binary star system. After a minute of running, the orbit began noticeably expanding: Why is it happening, and is this natural? The source ...
WarpPrime's user avatar
  • 6,683
0 votes
1 answer
151 views

Are there any good images of Sirius B at apastron in the Sirius system?

Sirius B has a distance to Sirius A of 11 arc seconds at apastron; are there any good images of it at that point in its orbit?
user24634's user avatar