IYA Live Telescope Today – Alpha Centauri

Article written: 26 Mar , 2009
Updated: 24 Dec , 2015

If you didn’t get a chance to watch the IYA telescope “live” on Galactic TV today, don’t worry. We took a video capture for you. Step inside to enjoy today’s view of Alpha Centauri…

Alpha Centauri (alpha Centauri / alpha Cen); (also known as Rigil Kentaurus, Rigil Kent, or Toliman) is the brightest star in the southern constellation of Centaurus and an established binary star system, Alpha Centauri AB (alpha Cen AB). To the unaided eye it appears as a single star, whose total visual magnitude identifies it as the third brightest star in the night sky. Alpha Centauri is the closest star system to the Solar System, being only 1.34 parsecs, or 4.37 light years away from our Sun.

Popularly known, Alpha Centauri is the closest star system to our Solar System. It lies about 4.37 light-years in distance, or about 41.5 trillion kilometres, 25.8 trillion miles or 277,600 AU. Astronomer Thomas James Henderson made the original discovery from many exacting observations of the trigonometric parallaxes of the AB system between April 1832 and May 1833. He withheld the results because he suspected they were too large to be true, but eventually published in 1839 after Friedrich Wilhelm Bessel released his own accurately determined parallax for 61 Cygni in 1838. For this reason, we consider Alpha Centauri as the second star to have its distance measured.

Alpha Centauri A is the principal member or primary of the binary system, being slightly larger and more luminous than our Sun. It is a solar-like main sequence star with a similar yellowish-white colour, whose stellar classification is spectral type G2 V.[12] From the determined mutual orbital parameters, Alpha Cen A is about 10% more massive than our Sun, with a radius about 23% larger.

Alpha Centauri B is the companion star or secondary, slightly smaller and less luminous than our Sun. This main sequence star is of spectral type of K1 V, making it more an orangish-yellow color than the whiter primary star. Alpha Cen B is about 90% the mass of the Sun and 14% smaller in radius. Although it has a lower luminosity than component A, star B’s spectrum emits higher energies in X-rays. The light curve of B varies on a short time scale and there has been at least one observed flare.

Together, the bright visible components of the binary star system are called Alpha Centauri AB (Alpha Cen AB). This “AB” designation denotes the apparent gravitational centre of the main binary system relative to other companion star(s) in any multiple star system.[15] “AB-C” refers to the orbit of Proxima around the central binary, being the distance between the centre of gravity and the outlying companion. Some older references use the confusing and now discontinued designation of A×B. Since the distance between the Sun and ? Cen AB does not differ significantly from either star, gravitationally this binary system is considered as if it were one object.

Alpha Centauri C, also known as Proxima Centauri, is of spectral class M5Ve or M5VIe, suggesting this is either a small main sequence star (Type V) or sub-dwarf (VI) with emission lines, whose B-V colour index is +1.81. Its mass is about 0.12 M. R.T.A. Innes from South Africa in 1915 discovered Proxima Centauri by blinking photographic plates taken at different times during a dedicated proper motion survey. This showed the large proper motion and parallax of the star was similar in both size and direction to those of ? Centauri AB, suggesting immediately it was part of the system and slightly closer to us than ? Centauri AB. Lying 4.22 light-years away, Proxima Centauri is the nearest star to the Sun. All current derived distances for the three stars are presently from the parallaxes obtained from the Hipparcos star catalog (HIP).

As always, you can visit the remote telescope by clicking on the IYA “LIVE Remote Cam” Logo to your right. We’ll be broadcasting whenever skies are clear and dark in Central Victoria! Enjoy….

Information Courtesy of Wikipedia

12 Responses

  1. Kevin F. says

    It says something about the distances involved that we’ve got about as much chance of resolving a planet around that system as we do of resolving on in a system many times farther away.

  2. ThereIsNoSuchThingAsMagic says

    Still, with recent advances in exoplanet imaging, we can finally resolve some exoplanets, though it is prolly harder to apply those techniques for binary star systems. What im curious about is whether anybody has searched the Alpha C system for exoplanets using the wobble and transit methods, and if any were found?

  3. Andrew James says

    text. Thank you for using this wikipedia text. Much of this was originally written by me about 18 months ago, and I never thought I’d see what I’ve written to appear in the leader.
    Furthermore, you can read my own The Imperial Star — Alpha Centauri article (in 9 parts on Southern Astronomical Delights
    As for the image, pity we don’t see the two stars of this well known binary system.
    Cheers for the article!
    (As for plagiarism forget it Tammy. I’m more than happy that you have used it.)

  4. bobfoot says

    “Information Courtesy of Wikipedia” is different from copying and pasting entire paragraphs from Wikipedia.
    Plagiarism is plagiarism, and lazy is lazy, no matter what you’re “writing” about.

  5. Andrew James says

    Furthermore, you can read my own The Imperial Star — Alpha Centauri article (in 9 parts) on Southern Astronomical Delights

  6. marcellus says

    Thank you Tammy. I was disappointed the YouTube video was unable to split A-B.

  7. One Angry Scientist says

    @ Andrew James:

    Enjoyed your website. Thanks for sharing!

  8. Member

    thank you, andrew james!

    to bobfoot (and others who may have felt dismay at my direct use of wikipedia…)

    the “information courtesy of wikipedia” will accompany each live telescope today article not because i am lazy, nor because i am a plagiariser – but because i will accept no money for what we are doing here.

    the IYA “live” telescope is a gift of love that has occurred on three parts: i donated the telescope and talked my observatory into allowing our stellacam to be used remotely for a year long project, northern and southern galactic donated the telescope pier, the website, the bandwidth and the time it takes every clear night to monitor the telescope and broadcast the image – and to record the view and send it to me; universe today has kindly donated the advertising not only to get the word out to the entire world, but to allow me the freedom to publish articles about what we’re doing, and in turn i donate my time again to turn the videos into You Tube, look up the information and post it.

    wikipedia also shares the same wonderful spirit – it’s a labor of love. the folks who contribute there freely give what they have written in a effort to educate any one who cares to read – with the caveat that if the material is used that you must also acknowledge the source.

    just as we who have donated our time to make the IYA live remote telescope happen can only hope our humble videos are of service of wikipedia and may one day grace their pages, we also hope that those who donate their time to wikipedia feel the same.

  9. Member

    ps – marcellus? keep an eye on the 7:00 position. we’re still working on using different filters, etc. we were just delighted that we stopped the “jerk” on the replay this time! it will improve… we promise!

    and we’ll revisit and see if we can’t split this puppy… 😉

  10. bobfoot says

    That’s lovely Tammy, but if you’re going to do that, don’t state plainly at the beginning: “written by Tammy Plotner”. “edited by” or “assembled by” or “gathered by” or “found by”. Not “written by”.

  11. Member

    it’s a automatic insert done by the website format – but i will make sure to put future disclaimers in. no problem!

  12. Vanamonde says

    For most of my life, only one star was been seen as something more than a point source. It is amazing to actually even this closest star as a disk.

    This *is* a Golden Age of Astronomy!!

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