Questions tagged [binary-star]

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

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43 views

Determining inclination angle of interacting binaries

Consider an interacting binary system. If the plane of their orbits is inclined by some angle $\theta$ around its semi major axis $a$ and some angle $\phi$ around its semi minor axis, is there a ...
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2answers
376 views

What exactly is the orbital period value of Sirius binary star system?

My Textbook An Introduction to Modern Astrophysics 2nd edition (2017), page 557 mentions that the modern value is 49.9 years. But Wikipedia mentions 50.1284±0.0043 years. Which is correct? Or, has the ...
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24 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 ...
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37 views

Virial theorem for a binary system

I am trying to derive the virial theorem but for two stars orbiting each other. I know the derivation for the general virial theorem with i particles but I am wondering if there is a quicker or more ...
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1answer
74 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 ...
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1answer
69 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....
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44 views

Spurious periods of stars

What exactly is meant by spurious periods of stars? E. Tanner writes in Spurious Periods in Spectroscopic Binaries in 1948 Furthermore: Can spurious periods be produced by aliasing, and how can they ...
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47 views

How likely are triple planet systems?

Is it likely to ever discover three planets of similar mass revolving around a common barycenter, or would such a system be too unstable? Such triple planet system would look like a triangle once in a ...
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35 views

Accretion disk formation

Why a mass transfer in a binary star system, from the less dense star to the denser star forms an accretion disk? Why the material does not fall directly to the denserstar?
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How to distinguish primary hosts (stars) and orbiting satellites (planets) and tertiary bodies (moons) by their mass and trajectory?

Suppose one has run a gravitational simulation of N bodies (has the mass, vector positions, vector velocities, etc for each body), but knows nothing a priori about ...
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150 views

How is phase defined in a binary orbit with eccentricity?

Are orbital phases of the black spot in the figure measured from some angle or time/period? Usually, how is phase=0 defined? It is relative to the line of apses perhaps with phase=0 at periastron? Any ...
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36 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 ...
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38 views

Orbital Angular Momentum of a Binary Star System

Let's say you have a binary star system, consider the orbital motion of that binary star consisting of two solar-like stars separated by 20 stellar radii. How would one calculate the angular momentum ...
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1answer
276 views

What exactly is “the rotating lighthouse model” in the context of a double pulsar?

The introduction to Testing the rotating lighthouse model with the double pulsar system PSR J0737-3039A/B (open access) says: The double pulsar system PSR J0737-3039A/B was discovered by Burgay et al....
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59 views

Orbit of Luhman 16?

I am studying some binary stars and brown dwarfs. Some orbits are known and easy to find, like Alpha Centauri. However, when I look for the orbital characteristics of Luhman 16 (AB), I only get the ...
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105 views

Which binary star system has a greatest angular distance?

Visible from the Earth, which binary star system has greatest angular distance ?
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47 views

Visual binary star with circular apparent orbit

Does anyone know a good example of visual (or interferometric) binary star apparent orbit of which looks circular due to projection though in fact is markedly elliptical? I need that for teaching.
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1answer
93 views

Fate of a planet orbiting a Lagrange point behind a star?

Let's say there is a planet orbiting at L5 behind a star, which is in turn orbiting a more massive star, like so: What is the ultimate fate of this planet? I'm predicting that it will spiral into the ...
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67 views

Is it correct to say that only binary and solitary star systems are stable?

Recently it has been shown that a large number of binary stellar systems exist. It seems to me that the orbits of stars in systems containing three or more stars will inevitably be chaotic, resulting ...
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Relation between inner and outer eccentricities in a hierarchical triple star system

According to Table 3 of Sterzik & Tokovinin (2002), the inner eccentricity of a triple star system (i.e. the eccentricity of the inner binary) is, most of the times (70%), larger than the outer ...
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63 views

What is the lifetime of an x-ray binary?

What would be the typical lifetime of an x-ray binary? I have trouble finding a reference.
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What is the relation between between hardness ratio(HR) and spectral state of a X-ray binary star system?

When reading about hardness ratio, it shows that depending on the hardness ratio spectral states of a binary star can be divided into soft, hard states. So how the HR value changes with respect to the ...
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1answer
112 views

Any known Triple Star Systems with this hierarchy?

I'm curious, are there any known STABLE triple systems in which a close inner binary pair is orbited by a more massive star, yet the total mass of the binary pair is greater than that single orbiting ...
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37 views

Interaction of stellar winds in binary star systems

Binary star systems are fairly common but I am unable to find any information on how the stars interact with one another on aspects other than gravitational affects. Using Alpha Centauri as the ...
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51 views

Eta Cassiopeiae star type; G0V? F9V? Both?

For a story I am looking into the star system of Eta Cassiopeiae, which is a binary with a main sequence star called Achird (very similar to the sun) and a K7V star. The issue I am running into is the ...
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1answer
36 views

Is HR 5171 a Spectroscopic Binary or a Symbiotic?

Is HR 5171, the largest yellow star in the galaxy a symbiotic star where one feeds off the other? Or is it a spectroscopic binary where its only possible to determine that there are two stars by ...
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52 views

Origin as binaries and multiple system

The majority of hot stars originate as binaries or multiple systems. How is it with the cooler spectral types? Are they usually born as single stars?
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123 views

Probability of planets in binary star systems?

There is much fiction on binary stars with planets, for whatever reason, and this keeps supporting the popular impression that those systems are frequent. Indeed, the methods for identifying ...
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1answer
51 views

Is a double quasi-binary system valid?

I was messing around with 4-body problems, and discovered a system where a close binary and a regular binary pair orbit each other. The regular binary gets disrupted every few orbits and one star ...
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52 views

Naming convention for multiple star systems

Okay, so I've seen different notations for the stars in β Capricorni. Some sources state that the stars are Aa, Ab1 and Ab2, Ba, and Bb, while others say that they are Aa, Aba and Abb, Ba, and Bb. So, ...
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1answer
136 views

Calculate the absolute magnitude for a multi-star system

We know that the absolute magnitude of a single star can be calculated with the formulae: $$M_{\rm bol} = 4.75 -2.5 \log_{10} \left(\frac{L_*}{L_{\odot}}\right)\ ,$$ $$M = -2.5 \log_{10}(L_* / L_0),$$...
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1answer
54 views

Is Adhara a member of binary star system?

During the initial days of Covid pandemic I discovered my interest in astronomy . I found it by gazing at night sky near Sirius that Adhara was undergoing a significant wobbling motion . I thought ...
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109 views

Question about orbital direction on binary systems

I wonder if is possible to find a binary system in which one star is orbiting the center of mass in one direction and the latter orbiting in the opposite direction. Would this transgress angular ...
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2answers
329 views

Calculating distance from center of mass of two stars in a binary system

I am confused on how to calculate the distances for each star in a binary system to their centre of mass. I am trying to solve it from a book I am reading which shows the solution but I do not ...
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1answer
47 views

Alfven Radius of mainsequence stars

Is there any average value for the Alfven radius of main-sequence stars? if there are no such values, then how may I calculate it??
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1answer
745 views

What do the words “p-type” and “s-type” mean?

As explained in various sources (such as that answer), a planet in an s-type orbit orbits one of the stars of a binary star system, whereas a planet in a p-type orbit orbits both stars. A synonym for ...
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1answer
323 views

Do main sequence stars in binaries transfer mass by Roche lobe overflow?

It is known that binary star components containing red giant can under go mass transfer when their radii exceeds the Roche limt. Do main sequence binary stars also undergo mass transfer by this ...
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1answer
50 views

Apparent Centering Problem When Using the Perifocal System to Draw Orbital Ellipses [closed]

I am attempting to render orbital ellipses in software. Given a set of orbital elements, I am using the Perifocal system to determine a set of points along the curve of the ellipse. I am using the ...
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2answers
169 views

Could there be a planet at the barycenter between two or more stars revolving around each other?

In binary star systems, could there be a planet the stars revolve around, with eternal day on all sides? 1st scenario: Imagine a binary system consisting of two Sunlike G5V stars of 1 solar mass each, ...
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1answer
118 views

Question about semi-major axis mean separation

I am currently doing an assignment but I cannot for the life of me understand what one of terms used means. Notice I am not trying to get help with the assignment itself, but rather to make me ...
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2answers
127 views

Binary Star Initial Speed

I am writing a 2D simulation for binary stars orbiting each other. Currently, the initial position of the stars are on opposite sides of the screen with the left star having a velocity up the page and ...
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Why are the W UMa variable subtypes labelled “A” and “W”?

The W Ursae Majoris variables (eclipsing contact binary stars) are divided into the A- and W-types. As described in Wilson (1978) "On the A-type W UMa systems": There are two recognized ...
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1answer
64 views

The definition of eclipsing binary star systems

In the second minimum (the 3rd step) there is a smaller decrease in light intensity. For this to happen, wouldn't you need to be looking at the plane of orbit from above rather than directly along the ...
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1answer
170 views

Fractional contribution of secondary star

What do we mean by "the luminosity fraction" and "the fractional contribution of the secondary star" of binary stars? can anyone suggest any method to calculate them theoretically?...
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6th catalogue of orbits of visual binary stars

I wanted to download or access the US navy catalog " the sixth catalog of orbits of visual binaries". I have already tried USNO web site and vizier. but I couldn't see them there. The link was dead ...
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Is Beta Lyrae still thought to be losing mass in a spiral outflow?

In the famous 1960 painting by Chesley Bonestell, Beta Lyrae is depicted with a glowing spiral trail of matter emanating from the binary stars. I'm wondering if that's still thought to be a ...
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1answer
51 views

Binary star data

I was doing a project on Binary stars. I wanted data of masses, eccentricity, semi-major axis, and radial velocity. I tried many sites but I couldn't find them. Where can I download such data from?
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51 views

Binary stars and gas giant formation

Say there's a young s-type binary star system with 2 Sun-like stars. From what I understand for a stable orbit to be possible, a planet's farthest orbital point from its host star has to be around 1/5 ...
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1answer
219 views

Total apparent magnitude of eclipsing binary system

This is a question from the 2016 USAAAO national exam, for which no solutions are given: An eclipsing binary system has a magnitude $m_p$ = 14.2 during the primary transit and $m_s$ = 13.7 during ...
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103 views

Combined mass of binary stars

This is Question 17 from USAAAO Practice Round 2015. The answer is D. It would be best if someone can detail out the workings. In a nearby star system, two stars are seen to orbit each other every ...