Questions tagged [binary-star]

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

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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
22 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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34 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? Many thanks.
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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
38 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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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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43 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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53 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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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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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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42 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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696 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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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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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
118 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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52 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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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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46 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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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
48 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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Radial velocity data in ALADIN or TOPCAT for Binary Systems

I just installed both, Aladin and Topcat VO tools. I want to know how to search for: HD 226868 and A0620-00 radial velocity data or photometric curves to derive the hidden black hole mass in those ...
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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
107 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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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 ...
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PHOEBE 2.2 Documentation, components and semi-major axis definitions

I'm looking at PHOEBE 2.2 Documentation, specifically at a tutorial about constraints What are Constraints? Constraints live in their own context of the Bundle, and many are created by default - ...
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34 views

Binary star system effects at the barycenter

I haven't been able to find anything on this so far. Using Alpha Centauri as the study, what events/effects ( if any ) would happen between the two stars? More specifically, between the gravitational ...
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47 views

Binary planet orbital distance

From reading various sources online, I see that some people talk about binary planets in very tight orbits (around 1 or 2 planet radii). I am wondering if it is possible for a binary planet (Double ...
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1answer
117 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 ...
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How to get data on Low mass x-ray binaries in M31 (Andromeda) Galaxy?

So my question is pretty straight forward, I am currently working on a project on finding X-ray emission counterparts for optically observable objects and was trying to get data on Low mass x-ray ...
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Do all High-Mass X-Ray Binaries have observable supernova remnants surrounding them?

I am studying high mass X-ray binaries, which are star systems that generally contain a neutron Star orbiting a larger companion. My assumption is that such systems began as two typical stars in ...
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1answer
44 views

Does the orbits of stars in a binary system have a common focus, which is the center of mass of the stars?

I know that when a planet orbits a star (and assume the star is stationary because its mass is >> the mass of the planet), the orbit is an ellipse, and the star sits at one of the foci of the ellipse. ...
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1answer
169 views

Semi-major axis in a binary star system

The semi-major axis a here, what exactly does it represent? Point it out in the image below.
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52 views

QQ Boo binary star

I need infos about this binary star, QQ Boo, when did it discovered, infos about each star in the binary system and infos about its light curve. I have already search through simbad and aavso websites ...
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162 views

How many exoplanets have been found around binary stars?

This XKCD whatif talks about circumbinary and [the other kind of] exoplanets. How many such exoplanets have actually been discovered? I tried to look it up at exoplanets.org, but didn't find a column ...
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1answer
5k 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 (...
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3answers
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Why are there so many binary systems?

Most star systems are binary, but why is that? Why would new stars form close to others, and not (relatively) evenly spread? And even if they are clustered close together, why are the majority binary? ...
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Where does Love's number come from in $\delta m = \frac{1}{2}k_2M_2\lbrace\frac{R_1}{r_\star}\rbrace^3$, the formula for the mass of a tidal bulge?

My question refers to page 165 of this paper. Specifically, how does one derive the equation $\delta m = \frac{1}{2}k_2M_2\lbrace\frac{R_1}{r_\star}\rbrace^3$ for the mass of a tidal bulge? A full ...
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146 views

Why is a giant planet around a tiny star unusual when binary stars are normal?

Inspired by this BBC article and the corresponding journal article about the M dwarf star GJ 3512. The Jupiter-like world is unusually large compared with its host star, contradicting a widely held ...
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Night-Day Cycles in S-Type Planetary Systems

I am a writer and space enthusiast. For a story I am currently writing I would like to have a planet which orbits a star which resembles the sun, which in turn orbits another star. In this situation ...
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Derivation of a formula for the mass of a tidal bulge and tidal torque

I've been looking into the tidal mechanism for a binary star system and seem to have hit a brick wall. In the literature (see below), little explanation is given to justify the equations (9.60), (9.61)...
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1answer
116 views

By convention, when observing an exoplanet, is the observer's line of sight (on Earth) perpendicular to the plane of sky?

This is just a quick question. In this picture of the orbit of an exoplanet, is the observer's line of sight perpendicular to the plane of reference, which is in the +z direction on the diagram? In ...
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3k 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 ...
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0answers
50 views

Could an Applegate-like mechanism operate in AM CVn systems?

One of the controversies surrounding the detection of exoplanets around post-common envelope binaries is the possibility that the orbital period variations observed might be the result of the ...
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Depth of primary and secondary minimum in a light curve

How can I explain approximately the same depth of primary and secondary minimum in light curve? I observe star HD 36486. I tried filters MOST and BRITE. Is it related with photometric filter? When ...
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2answers
279 views

How does one calculate inclination from a graph of radial velocity?

If a binary star system has a non-zero inclination, how would that show up in a graph of radial velocity? How could I then extract the inclination from the graph?
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How accurate are the new visualisations of V404 Cygni

A number of pictures and some animations similar to the ones below have had much press recently. Clearly the colours are artificial, but I wondered how accurately the represent the geometry of the ...
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1answer
120 views

How to improve efficiency in periodicity detection?

Our data set has $10^4$ data points, but has a long baseline and many gaps. If we bin the data, there would be $10^8$ data points ($[t,\rm {value}]$), but only about 1% are non-zero values. How to ...