Many thanks again to AIAS Fellow Russ Davis in Florida! These are useful source papers for the same data as I used yesterday. So this is a valuable check by Russ Davis. When converted into S. I. units they give
M = 7.956 ten power 36 kilograms
a = 1.4245 ten power 14 metres
eps = 0.8831
T = 15.56 earth years
so I can now proceed to calculate delta phi = 6 pi MG/ (c squared a (1 – eps squared)) radians per second and convert to degrees per orbit using the orbital interval of 15.56 earth years.
Sent: 17/04/2017 21:41:01 GMT Daylight Time
Subj: Re: PS to Parameters of Source 2 (Star S2)
Hi Dr. Evans,
I found the following references which identify some of the challenges to achieving an accurate data set for the S stars near the Milk Way center. Perhaps the inconsistent published data you are finding relates to these issues, at least in part.
For convenience, I included both of these papers as file attachments to this email.