Questions tagged [binary-star]

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

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Calculating the parameters of binary systems?

If I know the masses of the two bodies (they have equal mass), how do I calculate the two ellipse eccentricities, length of the apoapsis and speed at the apoapsis, that make stable system, as in this ...
7 votes
1 answer
85 views

Meaning of Bidirectional Arrow in a Fitting Formula

I was reading this paper on the ejecta mass of compact binary mergers and came across this notation in equation (6): $$\frac{M_\text{dyn}}{10^{-3}M_\odot}=\left(\frac{a}{C_1}+b\frac{M_2^n}{M_1^n}+cC_1\...
2 votes
1 answer
67 views

Why are the largest stars, such as O-type or B-type, most likely to be in multi-star systems; while red dwarfs are least likely?

I was just reading about what percentage of stars in our galaxy and, perhaps, other galaxies are in binary systems (or trinary... etc.). Researchers keep going back and forth about whether or not most ...
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1 vote
1 answer
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Calculating the expected lifespan for a binary system

I’m doing some research work on finding a correlation between the mass of binary stars and their lifespan. I have methods to find the mass, and that department seems to be going fine, but is there a ...
1 vote
1 answer
50 views

Modeling binary star using MESA

I'm trying to model a binary star using the MESA (Modules for Experiments in Stellar Astrophysics docs) code with an orbital period of 10 days with the scenario where mass transfers starts after the ...
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2 votes
1 answer
184 views

calculate the absolute and apparent magnitude for a binary star system

I'm used to use this formula to find the apparent magnitude of a star $$m_1 - m_2 = -2.5 log(\frac{f_1}{f_2})$$ If both star are at the same distance from us and their luminosity is the same, does it ...
5 votes
1 answer
362 views

What's the meaning of "hard supermassive black hole binary"?

In this paper, the authors state in the Introduction that A hard SMBHB [SuperMassive Black Hole Binary] can eject surrounding stars to transfer their orbital energy and angular momentum, which may be ...
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1 vote
1 answer
58 views

Binaries: mass and distance constraints

How does distance constrain the mass of the binary, please? Let us assume data like radial velocity, light curves, and astrometry. Is there any problem in the determination of the mass of the system ...
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4 votes
1 answer
216 views

Can insolation affect stars?

Stars glow with (almost) a black body spectrum. The fourth-power dependency on temperature means that there are large differences in surface brightness between hotter and cooler stars. The coolest ...
1 vote
0 answers
46 views

Period estimate [closed]

How would you estimate the period or range of periods for two stars, please? I know the right ascension, declination, and distance. I could estimate the masses and assume that the stars are in ...
10 votes
1 answer
2k views

How would a person know if a planet is orbiting a binary star?

I read in Neil deGrasse Tyson's book Astrophysics for People in a Hurry that scientists can tell if a star has a planet orbiting it because the light appears to shake. So if in the case of a binary ...
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4 votes
3 answers
119 views

Is there a logical reason why we see no back and forth aberration effects when observing binary stars?

I read this article, Questioning Einstein: Is Relativity Necessary? (Bethell (2010), Proc. Natural Philosophy Alliance, v.6, no. 2), regarding the 2 stars of Mizar A and wondering if it is true that ...
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4 votes
2 answers
649 views

Calculating the separation of binary stars

I'm struggling with the following problem: An eclipsing binary has period 0.10 years and each component has speed in its orbit of 19AU per year (or 90km/s) Assuming both stars have the same mass and ...
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3 votes
0 answers
67 views

Are there any binary red supergiants?

I wonder if we ever have identified or observed a pair of binary stars (red supergiants). And I also wonder what would happen if they exploded, (theoretically) as we haven’t observed it. Also, would ...
3 votes
1 answer
54 views

How to determine the amplitude of RV curve for eccentric orbit?

How to determine the amplitude of RV curve $$K_1$$ for eccentric orbit when the anomaly is not known, please? Thank you very much Edit: I thought that |RV_min-RV_max|/2 holds for circular orbits $e = ...
0 votes
2 answers
63 views

How to estimate limits for period of a binary?

How to estimate upper and lower limits for the period of a binary that is not eclipsing? What parameters are necessary, please?
2 votes
0 answers
131 views

What if the sun was replaced by Alpha Centauri? [closed]

What would happen if the sun suddenly got replaced with the entire Alpha Centauri system? Alpha Cen A will be in the sun’s position, with Alpha Cen B not too far off into the distance. How would this ...
2 votes
0 answers
46 views

If a planet orbits an M-Star in an S-type orbit around a G star, what is the minimum distance from the G star that it could remain tidally locked?

I'm wondering how close a planet-M-dwarf system could orbit a G star and have the planet remain tidally locked to the M star. I'm curious, because I'm designing a habitable planet, and I want the ...
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3 votes
2 answers
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What is the v sin i parameter?

In the August 2021 preprint by WeiJia Sun et al. Exploring the stellar rotation of early-type stars in the LAMOST Medium-Resolution Survey. II. Statistics there is histogram plot with the caption: v ...
3 votes
1 answer
74 views

Binary - when mass transfer starts

How to estimate when the mass transfer will start? What is the characteristic of pre-mass transfer binaries?
5 votes
1 answer
249 views

How would you calculate the "day" on a planet orbiting a red dwarf that is a companion to a larger star?

So the idea is you have an Earth-sized planet with a moon orbiting an M-class star (let's give it .25 solar masses) at 0.2 AU, with an orbital period of 63 days and a 24-hour day. Its orbit has an ...
6 votes
1 answer
544 views

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-...
5 votes
1 answer
53 views

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 ...
1 vote
1 answer
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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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1 vote
1 answer
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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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1 vote
1 answer
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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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1 vote
1 answer
32 views

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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0 answers
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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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1 vote
0 answers
39 views

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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1 vote
0 answers
15 views

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.
2 votes
1 answer
156 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 ...
1 vote
0 answers
58 views

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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7 votes
1 answer
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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 ...
5 votes
1 answer
229 views

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 ...
9 votes
1 answer
800 views

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 ...
4 votes
0 answers
27 views

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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4 votes
0 answers
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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 ...
5 votes
0 answers
37 views

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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8 votes
1 answer
310 views

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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1 vote
0 answers
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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 ...
2 votes
0 answers
262 views

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
1 answer
68 views

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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0 votes
1 answer
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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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3 votes
2 answers
402 views

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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2 votes
0 answers
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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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1 vote
1 answer
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Eclipsing binaries - definition with inclination

What is the definition of eclipsing binaries based on the inclination of their orbit and the sum of relative radii? Are close eclipsing binaries defined by an inclination greater than 60 degrees?
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-1 votes
1 answer
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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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0 votes
2 answers
43 views

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 ...
5 votes
2 answers
548 views

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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0 votes
1 answer
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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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