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If Kapteyn's star has a parallax angle of 0.255 arcsec, a proper motion of 8.67 arcsecs per year and a radial velocity of +246 km/s, What is the star's tangential velocity?

Answer 1

Lincoln Adams

#v_t=183.0dot(3)km# #s^(-1)#

#v_t# is given by the formula: #v_t=(4.75mu)/p#, where:

#v_t=(4.75*8.67)/0.225=183.0333...=183.0dot(3)km# #s^(-1)#

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Answer 2

Anna Armstrong

The proper motion and parallax angle of Kapteyn's star can be used to calculate its tangential velocity: Tangential velocity = Proper motion * Distance = Proper motion / Parallax angle. Since the parallax angle is 0.255 arcsec and the proper motion is 8.67 arcsecs per year, the tangential velocity is roughly 34.00 km/s.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.