Finding Potential Binary Systems
A binary system is two stars that share the same point of gravity. To identify a binary system an object must be observed at least twice and if the radial velocity of the object is significantly different then it implies that the object could be a binary system. To determine if the difference of the radial velocities is significant the value must be greater than the allowed difference determined by the error.
Note: There could be a difference of only 0.01 but it is up to the user’s discretion for how much of a difference is needed.
Below is an example completed using data from RAVE, this produces data where the difference in radial velocities is greater than the allowed difference of the errors with no additional analysis.
The lines ‘WHERE t1.Obsdate < t2.Obsdate AND t1.Obsdate != t2.Obsdate’ are to ensure that the dates aren’t the same nor repeated.
SELECT t1.Obsdate as t1_Obsdate, t2.Obsdate as t2_Obsdate, t1.RAVEID as t1_RAVEID, t2.RAVEID as t2_RAVEID, t1.HRV as t1_HRV, t2.HRV as t2_HRV, t1.eHRV as t1_eHRV, t2.eHRV as t2_eHRV, ABS(ABS(t1.HRV) - ABS(t2.HRV)) AS Difference_HRV, (t1.eHRV + t2.eHRV) AS Difference_eHRV FROM rave_dr5.RAVE as t1 INNER JOIN rave_dr5.RAVE as t2 on t2.RAVEID = t1.RAVEID WHERE t1.Obsdate < t2.Obsdate AND t1.Obsdate != t2.Obsdate AND ABS(ABS(t1.HRV) - ABS(t2.HRV)) > (t1.eHRV + t2.eHRV)