# Questions tagged [binary-star]

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

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### Effects of a binary star system on a tidally locked planet

This is basically a world-building question, but I'm looking for a scientifically based answer, so I'm posting here. Imagine a fairly earth-like planet- Lets call it Planet X. Planet X has an earth-...
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### Did de Sitter expect to disprove Ritz theory only with visual binaries?

Walter Ritz’s emission theory stated that some fraction of the velocity of an object was added to the speed of light emitted from it. Willem de Sitter pointed out a problem with this in the case of a ...
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### Mass of secondary normalized to 1 au

What does Mass of secondary normalized to 1 au in this catalogue https://vizier.cfa.harvard.edu/viz-bin/VizieR?-source=J/A+A/623/A72 mean, please? I tried to multiply that by Jupyter mass and the ...
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### Binary - semi-major axis computation

I tried this formula for WW Aur: $$a(R_\mathrm{nom}) = \sqrt[3]{\frac{P(\mathrm{d})^2}{365.2564^2}[M_1(M_{\mathrm{nom}})+M_2(M_{\mathrm{nom}})]} \cdot \frac{149597870.7}{695700}$$ What is wrong, ...
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### Computation of magnitude of the secondary

How to approximately compute the magnitude of the secondary in a binary when I know the magnitude of the primary, masses, radii, and approximate luminosities for both of them, please? Thank you very ...
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### Magnitude difference between companion in binary from mass difference in binaries

Is there any hypothesis on how to estimate the difference between visual magnitudes of binary components based on their masses? Thank you
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### V magnitude of binary components

Which catalog provides visible magnitudes of binary components, please? How to find it, for instance, in VizieR, please? I have a list of binaries.
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### Does latitude affect the sunset times between binary stars

Basically, if a binary system's stars sunset an hour apart at the equator, would they still set an hour apart in a much farther north latitude where the daylight lasts longer or is it still an hour ...
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### Transit Timing Variation data for binaries

Where can I find transit timing variation data (TTV) for binaries, please? Is there any database? Thanks a lot.
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### What happens if supernova undergoes in tightly close multi stars system

I do wonder in a tight or close orbital binary stars or multi stars system, if one stars undergoes supernova and that blast can lead another stars in the system to become supernova, too? Is there ...
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### What does it mean for something to be optically thick to pair production?

I have seen several references in the high energy astrophysics literature (including the example below) which make reference to an astronomical source being "thick to pair production". What ...
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### Difference between NSBH and BHNS mergers

What's the difference between Neutron Star-Black Hole Merger (NSBH) and Black Hole-Neutron Star Merger (BHNS)? Are they the same names for the same events or is there any difference between them? I ...
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### Metallicity in gravitational wave astronomy

Metallicity relates to the quantity of elements in an object that are heavier than hydrogen and helium. I often see this terminology in recent studies of gravitational waves such as this paper. If I ...
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### Limb darkening coefficients for BRITE and Johnson:V passbands

Where to find limb darkening coefficients for BRITE and Johnson:V passbands, please? Do any tables exist or are there any relations for their guest? Many thanks
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### How to determine the time of periastron passage (T) of a single lined spectroscopic binary?

I am working on finding spectroscopic elements of a single lined spectroscopic binary. All I have is irregularly spaced radial velocity data which needs to be phase folded to plot a velocity curve (RV ...
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### HR 6819 "Vampire" star - mass disparity in binary star system

Regarding the two B-type stars of the HR 6819 system, a recent news item (2 March 2022), European Southern Observatory researchers find 'vampire' star sucking outer layers of companion star states, ...
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### Post-Keplerian orbital parameters; is there a generally accepted set with definitions?

Strong-Field Gravity Tests with the Double Pulsar is a pretty big deal! 16 years of precision timing including "timing parallax" via VLBI has provided a dataset for which analysis requires (...
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### Is it completely false that the Sun does not revolve round the earth? In what sense? [duplicate]

This is a very naive question but I never fully understood this. For a system of two binary stars moving under the influence of their mutual gravitational forces revolve around their common center of ...
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### How to calculate orbital velocity of binary star?

I am trying to simulate the Alpha Centauri AB System. I built the simulation, it works flawlessly when trying to simulate our solar system, and I am now trying to simulate the AB System. I found all ...
1 vote
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### What can be the minimum time for a somewhat stable twin star orbit to collapse on being affected by a third body?

The third 'invading' celestial body passing by or crashing into one of the stars could be a possible reason for the orbit collapse. Something that throws the stars* off-course speeding up their death ...
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### What if a component of a binary star lies in the center of it's orbit and not in the focus?

I'm trying to solve this task: Observing a visual binary star with a highly elongated elliptical orbit for a long time, the astronomer noticed that the bright component lies in the center of the ...
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### How can eclipsing binaries be used to gauge distances?

I understand that we can infer much about the parameters, such as the radius and mass, of stars in eclipsing binary systems. But how can eclipsing binaries be used to gauge distances? The current ...
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### Did Gaia DR3 help figure out whether Albireo is an optical double?

Based on the Wikipedia page of Albireo, Gaia DR2 had too much noise to determine whether the stars are physically associated or if they are just an optical double. Gaia DR3 was released last year. ...
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### Is the claim that the star Sirius does not precess like other stars true?

There is this popular claim on Internet that the star Sirius does not precess like other stars. The idea comes from mainly Greeks and Egyptians using Sirius to track seasons, as part of the Sothic ...
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### Semimajor axes data from Kepler Eclipsing Binary Catalog

I have been searching for a massive binary (>7 M$_{\odot}$) catalog with semimajor axes given, but I wasn't able to find any, and I began to search for a binary star catalog and decided to filter ...
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### How to calculate eclipses on a planet in a binary star system

I posted this question on the physics page but decided it might be best if I post it here instead as it may be a more astronomy related question. I also haven't received any answers over there so far ...
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### Question about calculating the ratio of volumes of two components of an eclipsing binary star

I'm trying to solve this task: At the maximum, the eclipsing binary star has a brightness of 6^m, and at a minimum of 8^m. Considering the eclipse to be central and the companion to be dark, find the ...
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### 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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### 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 ...
1 vote
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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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 ...
1 vote
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### 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 ...
1 vote
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### 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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### 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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