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Earth from Epsilon Indi

  1. Dec 20, 2014 #1
    Hi,

    I wonder if anyone can answer the following: -

    What constellation would our sun appear in if viewed from Epsilon Indi?

    Thanks in advance

    Chinspinner
     
  2. jcsd
  3. Dec 20, 2014 #2

    Vanadium 50

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    Epsilon Indii would not have the same constellations we do. However, the sun would be in the general direction of Ursa Major.
     
  4. Dec 20, 2014 #3
    Excellent. Thanks very much.
     
  5. Dec 21, 2014 #4

    chasrob

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    Here's the view from epsilon Indi from the astronexus page-looks like you just extend a line from the bottom of the cup of the big dipper (which looks the same as from earth).
    epindi_zps9a316c43.png
     
    Last edited: Dec 21, 2014
  6. Dec 21, 2014 #5
    That is brilliant, thanks Chasrob.
     
  7. Dec 21, 2014 #6

    chasrob

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    Here's a less cluttered version-as Vanadium said it's in Ursa Major; other stars have moved, like Arcturus and alpha Centauri...
    epindi3_zps708d1c50.png
     
  8. Dec 22, 2014 #7
    And Big Dipper is still there.
    Out of 21 brightest stars in sky, brighter than +1,4 on Sun, 11 are closer than 100 lightyears, and 10 are remoter. Of the next 26 (+1,4 to +1,99), 4 are.

    Regarding the Big Dipper, most of it is an open cluster, meaning the stars stay together when viewing it from a different nearby point of view. The stars that stand out are the stars at the ends - Alkaid and Dubhe - which are behind the rest, at 101 and 124 lightyears respectively, and Megrez in the middle which is in front, at 58 lightyears. The other four are all between 78 and 84 lightyears of Sun. So moving away from Big Dipper, towards Indus, produces little distortion... only slight dimming and shrinking.
     
  9. Dec 22, 2014 #8

    Vanadium 50

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    Yes, the Big Dipper asterism persists. (One might argue that sol makes an eighth star, but I expect it's dimmer than Megrez) Some will - particularly those with the stars far away - and some won't. For example, Gemini's Castor and Pollux are relatively unchanged, but are now joined by Procyon (now in Gemini, or possibly Cancer) and Sirius has left Canis Major and joined Canis Minor.
     
  10. Dec 22, 2014 #9
    No.
    Sun is about +2,8. Megrez will have faded from the +3,31 on Sun to +3,7. Merak and Phecda, having faded from about +2,4 to +2,7 are only slightly brighter than Sun; Dubhe only fades from the +1,79 to +2,0.
    So what does that extra star make Dipper into?
    As for Indus itself, Epsilon at +4,69 is the sixth brightest star. The brighter five are all further than 97 lightyears. (but not so much brighter, so Epsilon will be missed)
    In Ursa Major, the stars to the foreground of Dipper (that shrink towards Dipper and fade) include
    Talitha Borealis (48 ly, +3,12)
    Al Haud (44 ly, +3,17)
    Alula Australis (27 ly, +3,79)
     
  11. Dec 22, 2014 #10

    chasrob

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    That page--http://[URL='http://www.astronexus.com/endeavour/chart']www.astronexus.com/endeavour/chart[/URL] [Broken] -- is a lot of fun to play around with. Here's a zoom out with constellations added-
    epindi5_zps0bb09c96.png
    Castor and Pollux have moved slightly north into Lynx. Procyon and Sirius are in the northern reaches of Cancer, Arcturus has changed constellations. But the biggest move is alpha Centauri (here called Rigil Kentaurus). From the far south to the north in Ursa Major below the dipper. Maybe you pass it by on your way to epsilon Indi?
     
    Last edited by a moderator: May 7, 2017
  12. Dec 23, 2014 #11
    Sticking to the Earth constellation borders. Essentially, they make Twins into Quadruplets.
    Of course - it is the nearest star.
    Probably yes!
    The nearby sunlike stars are funnily clustered:
    Rigil Kentaurus at 4,3 ly
    Epsilon Eridani, 61 Cygni, Tau Ceti and Epsilon Indi all four between 10,5 and 11,9 ly
    and then next Keid at 16,5 ly.

    But how does the sky look like from Rigil Kentaurus? Specifically, where does Rigil Kentaurus AB orbit lie in Rigil Kentaurus sky?
     
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