Binary Stars Observable with Binoculars: Periodicity

In summary, there are no known binary stars that can be observed with binoculars and have orbital periods that can be observed from week to week or month to month. Even for shorter orbital periods, the stars would have to be very close together, around 1 AU or less. The closest binary star, Alpha Centauri, can be viewed with a modest telescope, but it is not currently possible to resolve it with binoculars due to the small separation between the stars.
  • #1
thetexan
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Are there any binary stars that can be seen with binoculars which have orbital periods you can observe from week to week or month to month?
tex
 
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  • #2
Not that I know of. I don't even know of any of that orbital period where you can resolve both stars through a telescope. For such a short orbital period the two stars would have to be very close together. Somewhere on the order of 1 au or less, depending on the masses of the stars. There are no telescopes for visual observation able to resolve two stars that close.
 
  • #3
Algol has a period just under 3 days. You cannot resolve the individual stars, but you can see the decrease in brightness - even with the naked eye - when the dimmer star eclipses the brighter. Algol goes from a bright second magnitude star to a relatively dim third magnitude star. This dim period lasts for 10 hours.
 
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  • #4
thetexan said:
Are there any binary stars that can be seen with binoculars which have orbital periods you can observe from week to week or month to month?

Not that I am aware of ...unless they were substantially sized bino's ( haven't personally tried the BIG ones)

Alpha Centauri is easily split with a modest 6" reflector or a reasonable refractor ( been doing that and showing others since I was a kid)Dave
 
  • #5
davenn said:
Not that I am aware of ...unless they were substantially sized bino's ( haven't personally tried the BIG ones)

Alpha Centauri is easily split with a modest 6" reflector or a reasonable refractor ( been doing that and showing others since I was a kid)Dave
Is it still possible?
Being the nearest binary, Alpha Centauri should be the easiest to see moving. (Any more distant, and a binary is either hard to resolve if short period, or slow moving if long period).
https://upload.wikimedia.org/wikipedia/commons/e/ee/Orbit_Alpha_Centauri_AB_arcsec.png
The separation of Alpha Centauri was at a global maximum around 1980. It is now near the local minimum. The global minimum is due in 2037.
Can you now, at the local minimum, resolve Alpha Centauri by binoculars, without excessive shaking?
 
  • #6
snorkack said:
Can you now, at the local minimum, resolve Alpha Centauri by binoculars, without excessive shaking?

haven't tried over the last few years
I was looking at Alpha Cent. on Saturday nite with a group of people I took out for their first telescope and deep sky imaging session.
Used it as one of the 3 alignment stars for the GOTO scope. Looked at it so quickly, I cannot remember if I could split it or not.Dave
 
  • #7
I calculated somewhat optimal conditions: let's imagine we would have two 100 solar mass stars orbiting each other at a distance of just 4 light years to us. We do not have those, of course. To get an orbital period of 1 month with circular orbits, the separation would be 1.1 AU, about 0.9 arcseconds in the sky. That still needs a telescope.

Edit: fixed missing factor of 2.
 
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1. What are binary stars?

Binary stars are a pair of stars that orbit around a common center of mass. They are held together by gravity and can be either bound or unbound to each other.

2. How can I observe binary stars with binoculars?

Binoculars with a magnification of at least 10x and a large aperture are recommended for observing binary stars. Look for pairs of stars that appear close together in the sky, and use binoculars to get a closer look.

3. What is periodicity in binary stars?

Periodicity in binary stars refers to the regular and predictable pattern of the stars orbiting around each other. This can be observed through changes in brightness or the motion of the stars.

4. Can I observe the periodicity of binary stars with binoculars?

Yes, with the right equipment and conditions, it is possible to observe the periodicity of binary stars with binoculars. However, a telescope with a higher magnification may provide a clearer view.

5. What types of information can be gathered from observing the periodicity of binary stars?

By observing the periodicity of binary stars, scientists can gather information about the masses, sizes, and orbits of the stars. This can help us better understand the formation and evolution of these stellar systems.

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