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A star located 135 degrees from the solar apex on the celestial sphere

  1. Jul 4, 2005 #1


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    I posted this in the homework help section but got no responses so I thought I'd try posting it here.

    I want the answer to the question, but really I'm looking for the relationship between the values.

    Q: A star located 135 degrees from the solar apex on the celestial sphere is at rest in the LSR 15pc from the sun, whose radial velocity with respect to the sun may be taken to be 20km/s. As seen from the sun, (a) what is the star's radial velocity; (b) how many seconds of arc will this star appear to move on the celestial sphere in ten years; (c) in what direction will it move

    So really what I'm asking here is what the relationship between radial velocity and angular separation from the solar apex is and how to apply that to parts b and c.

    Thanks for any assistance.
  2. jcsd
  3. Jul 5, 2005 #2


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    You probably know the standard solar motion with respect to the LSR (I am sure this value can be found in internet). Then you should find out the difference between both vectors. I am sorry but I am not familiar with this kind of exercises, however, it seams to me that 135 degrees from the solar apex is not a complete description of the stars coordinates which allows answering these questions.
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