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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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3 votes
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Single, binary, triple, .. fraction of star systems in our galaxy by mass

What is the fraction of single, binary, triple and so on systems as a function of one of the stars masses (or their sum)? This can be either derived from simulation or measurement. I feel like I have ...
SpaceCore's user avatar
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1 vote
0 answers
21 views

How can I use SDSS archive to find the radial velocities of binary stars?

I need to plot a radial velocity curve of a given binary star system, and I think that the SDSS apogee survey has what I need, but I havent had any luck finding anything on it. It this the right tool ...
Zandini3's user avatar
4 votes
1 answer
119 views

Extend CDF to physical range

Consider the following observations regarding the eccentricities of stellar binaries (just an example): $$e = [0.3, 0.45, 0.2, 0.52, 0.64, 0.34]$$ We can calculate the cumulative distribution function ...
RKerr's user avatar
  • 195
0 votes
1 answer
40 views

Resource suggestions?

I am a high school student and this is my first post. If I want to research binary stars (how to find out about their properties from their light curves) and I need to know how to interpret light ...
Golden_Hawk's user avatar
2 votes
0 answers
55 views

T Coronae Borealis

As it will explode this year or so, I became interested in the binary T Coronae Borealis. According to wikipedia, https://en.wikipedia.org/wiki/T_Coronae_Borealis R Cor Bor the binary masses are 1.34 ...
riemannium's user avatar
5 votes
0 answers
128 views

Why do double neutron stars remain bounded?

I read that in principle, the formation of a double neutron star requires that at the time of the second supernova explosion the binary consists of a $\sim$ 1.4 solar mass neutron star, and a second ...
some_math_guy's user avatar
1 vote
0 answers
44 views

How do changing binary separation and Roche Lobe size of the donor affect the long-term evolution of a binary under conservative mass transfer?

I computed that for a binary system that undergoes conservative mass transfer from the Roche-lobe filling Start 2 to Star 1 (i.e. $\dot M_2<0, \dot M_1=-\dot M_2$ and the change in angular momentum ...
some_math_guy's user avatar
3 votes
0 answers
122 views

Two Suns vs Two moons in the Sky

How rare is it to have 2 stars or 2 celestial bodies at least as big as our moon and sun in the sky of a habitable planet? What are the chances of both?
Justintimeforfun's user avatar
10 votes
3 answers
2k views

Are multiple stars actually more common than singles?

In the book by Neil Tyson & Michael A. Strauss & J. Richard Gott titled "Welcome to the Universe: An Astrophysical Tour" there is a sentence that starts: "Since more than half ...
Jimmy Bionic's user avatar
4 votes
2 answers
184 views

Are there naked eye binary stars with periods less than 100,000 years?

An optical double is two stars which appear very close together because they chance to be lined up as seen from Earth but are actually tens, hundreds or thousands of light years apart in space. A real ...
M. A. Golding's user avatar
4 votes
1 answer
319 views

How long would we survive an approaching neutron star?

I recently came across PSR B1620−26. A neutron star that captured a sun like star with an orbiting planet. The system went through several stages of development, but through it all the orbiting planet ...
Bradtvford's user avatar
2 votes
1 answer
251 views

For binary stars, what is the average semi-major axis?

Note I'm exclusively considering binary stars, not 3+ star systems. Binary stars come in all extremes. Wikipedia says that their orbital periods can be a few hours, a few days, or hundreds of ...
DrZ214's user avatar
  • 1,960
-5 votes
2 answers
163 views

Is Proxima Centauri a Planet?

Proxima Centauri meets all the requirements for Planet status, although it is a star, can an object be a star and a planet at the same time? normally, the answer should be no, but this is the problem ...
Benjamin1945 's user avatar
4 votes
3 answers
226 views

Keplers laws and this question

A planet (mass m) is orbiting a star (mass M) at a distance a. The distance of the star from the centre of gravity of the system is a' . Show that $$ MP^2 = a^2(a-a') $$ So first we can assume that $M ...
Moiz khokhar's user avatar
0 votes
1 answer
56 views

What is a dM1e red dwarf star? What do the '1' and 'e', specifically, stand for?

The Castor-and-Pollux Gemini Dioscuri system contains several red dwarfs classified as type 'dM1e' stars. I believe the d is dwarf, the M is M-type (redundantly designating a red dwarf?). What do the '...
Kurt Hikes's user avatar
  • 5,087
1 vote
1 answer
216 views

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 ...
Domahidi Péter's user avatar
7 votes
1 answer
90 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\...
hikari30's user avatar
2 votes
1 answer
141 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 ...
Kurt Hikes's user avatar
  • 5,087
1 vote
1 answer
114 views

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 ...
Vedant 's user avatar
2 votes
1 answer
116 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 ...
Mac Fly's user avatar
  • 21
2 votes
1 answer
2k 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 ...
InvisibleParticle's user avatar
5 votes
1 answer
396 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 ...
Jim421616's user avatar
  • 2,528
1 vote
1 answer
67 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 ...
Anna-Kat's user avatar
  • 505
4 votes
1 answer
221 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 ...
Kevin Kostlan's user avatar
1 vote
0 answers
47 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 ...
Elena Greg's user avatar
11 votes
2 answers
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 ...
Tardy's user avatar
  • 255
4 votes
3 answers
135 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 ...
Dubious's user avatar
  • 49
4 votes
2 answers
1k 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 ...
Ray61's user avatar
  • 43
3 votes
0 answers
82 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 ...
schrodingerscat's user avatar
4 votes
1 answer
102 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 = ...
Elena Greg's user avatar
1 vote
2 answers
79 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?
Elena Greg's user avatar
2 votes
0 answers
200 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 ...
Prince Pugs's user avatar
2 votes
0 answers
64 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 ...
Elhammo's user avatar
  • 1,107
3 votes
2 answers
373 views

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 ...
Elena Greg's user avatar
3 votes
1 answer
120 views

Binary - when mass transfer starts

How to estimate when the mass transfer will start? What is the characteristic of pre-mass transfer binaries?
Elena Greg's user avatar
5 votes
1 answer
292 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 ...
PrincipledStarfish's user avatar
6 votes
1 answer
776 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-...
user1642529's user avatar
5 votes
1 answer
67 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 ...
D R Ball's user avatar
1 vote
1 answer
104 views

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 ...
Anna-Kat's user avatar
  • 505
1 vote
1 answer
106 views

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, ...
Anna-Kat's user avatar
  • 505
1 vote
1 answer
70 views

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 ...
Anna-Kat's user avatar
  • 505
1 vote
1 answer
34 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
Anna-Kat's user avatar
  • 505
1 vote
0 answers
27 views

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.
Anna-Kat's user avatar
  • 505
1 vote
0 answers
43 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 ...
Dsport's user avatar
  • 11
1 vote
0 answers
17 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.
Elena Greg's user avatar
2 votes
1 answer
497 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
1 vote
0 answers
59 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 ...
Aung Satt's user avatar
  • 165
7 votes
1 answer
98 views

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 ...
georgeamccarthy's user avatar
4 votes
1 answer
249 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 ...
Junaid Ihsan's user avatar
9 votes
1 answer
822 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 ...
Junaid Ihsan's user avatar

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