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Thread: Mintaka (Delta Orionis)

  1. #1
    Join Date
    Jan 2006

    Mintaka (Delta Orionis)

    Mintaka (Delta Orionis)
    Here is what I know so far:
    A double, double system with the primary pair being orbited by the C component, that is orbited by the D component. The c is 15000 AU from the primary pair and the D is 75 AU from C.

    From Kahler:
    The star is wonderfully complex. A small telescope shows a seventh magnitude companion separated by almost a minute of arc. At Mintaka's distance of 915 light years (very nearly the same as Alnitak at the eastern end of the belt), the faint companion orbits at least a quarter of a light year from the bright one. In between is a vastly dimmer 14th magnitude component. The bright star we call Mintaka (whose solo magnitude is 2.23) is ALSO double, and consists of a hot (30,000 Kelvin) class B, slightly evolved, giant star and a somewhat hotter class O star, each radiating near 90,000 times the solar luminosity (after correction for a bit of interstellar dust absorption), each having masses somewhat over 20 times the solar mass. This pair is too close to be separated directly. The duplicity is known through the star's spectrum (its rainbow of light), which detects two stars orbiting each other every 5.73 days, and also because the stars slightly eclipse each other, causing a dip of about 0.2 magnitudes.
    Being only 915 ly away I would have thought that I could find more about this system. The SDSS picture is nice but not informative. I have the following questions:

    When will the primary pair go supernova?
    What are the masses of the C and D components and do they have designations?
    What would an orbital 3D plot look like of the system?
    What will most likely happen to C and D when the primary pair go supernova.
    Are there any planets in the system?
    Do we know or have any theories as to how the system formed?
    What are the individual metalicities of these stars; i.e. are they POP I or POP II?

    Any links or further information would be greatly appreciated. I tried arXiv and the HIP catalog but found nothing in the former and can't figure out how to use the later.


  2. #2
    Join Date
    Sep 2006
    Quote Originally Posted by jlhredshift View Post
    Mintaka (Delta Orionis)
    Here is what I know so far:

    Any links or further information would be greatly appreciated. I tried arXiv and the HIP catalog but found nothing in the former and can't figure out how to use the later.
    I suggest you start by going to SIMBAD

    and entering "Mintaka" into the "query by identifier" box.
    You'll receive a list of ID numbers, showing the star's
    entry in many different catalogs, some basic measurements,
    plus links to additional measurements.

    Next, I'd note the "Display references" section of the page
    returned by SIMBAD. It says that there are 312 technical
    papers which refer to Mintaka during the period from 1983
    to the present. You can generate a list of these papers,
    and then scan the titles; pick the most promising papers,
    and read their abstracts. Then, pick the most promising
    of THOSE papers, and read the entire text -- most will be
    available to you thanks to NASA's Astrophysics Data Service

    It will take you a few hours, but you'll probably be able
    to find 3 or 4 good papers which present the data you
    need to know to answer your questions ... if we know it.

    Good luck.

  3. #3
    Join Date
    Oct 2001
    Quote Originally Posted by jlhredshift View Post
    I tried arXiv and the HIP catalog but found nothing in the former and can't figure out how to use the later.
    To use the HIP catalog, just go to the Hipparcos catalog search page and enter the HD or HIP number of the star, if you know it (Mintaka is HD 36486), and it will find the Hipparcos catalog entry for the star. If you don't know the number, you can enter the RA & DEC to search. The Hipparcos parallax for Mintaka is 3.56 milliarcseconds. The get the distance in parsecs, it's just 1 over the parallax in arcsec; 1/0.00356 = 280.89888. To translate that into light years multiply by 3.26; 3.26 * 280.89888 = 915.73034. Of course that is too many significant figures, the best you can really say is that the distance is about 916 light years, about wjere Kaler put it.

    There is at least one interesting paper in arXiv which you might have missed. I found it in the NASA ADS database, which I always search first (becuase it links back to arXiv, but has a lot of stuff that arXiv does not): Tomographic Separation of Composite Spectra. VIII. The Physical Properties of the Massive Compact Binary in the Triple Star System HD 36486 (delta Orionis A), Harvin, et al., ApJ 565(2): 1216-1230. They give the component masses of the spectroscopic binary as 11.2 & 5.6 solar masses, and an orbital inclination of about 67 degrees. They also suggest that it is very nearly a contact binary, and may infact have already experience one mass ration reversal because of that (i.e., the primary now used to be the secondary). I don't see any other papers on Mintaka.

    As to when they will go SN, nobody knows. They are stll main sequence stars, so if they were singles, they would have to get off the main sequence first, and that would mean at least a million years or so, most likely more, from now, before they go boom. But I don't know how the binary pair will work; they could lose a lot of mass due to binary winds.

  4. #4
    Join Date
    Jan 2006
    Most excellant!!

    Thank you

    Now .. work work work

    But I love it

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