Stellar rotation depends on different parameters such as age , mass , initial chemical composition , initial angular momentum , and environment characteristics .
The range of values of these parameters causes the dispersion in the rotation period distributions observed in young stellar clusters/associations .
We focus our investigation on the effects of different circumstellar environments on stellar rotation .
More specifically , we consider the effects of a perturber stellar companion on the accretion-disc lifetime at early evolution stages . We are searching in stellar Associations for visual triple systems where all stellar parameters are similar , with the only exceptions of the unknown initial rotation period , and of the circum-stellar environment , in the sense that one of the two about equal-mass components has a close-by third ’ perturber ’ component . In the present study we analyse the 35-Myr old visual triple system TYC 9300-0891-1AB + TYC 9300-0529-1 in the young Octans stellar association consisting of three equal-mass K0V components .
We collected from the literature all information that allowed us to infer that the three components are actually physically bound forming a triple system and are members of the Octans Association .
We collected broad-band photometric timeseries in two observation seasons .
We discovered that all the components are variable , magnetically active , and from periodogram analysis we found the unresolved components TYC 9300-0891-1AB to have a rotation period P = 1.383 d and TYC 9300-0529-1 a rotation period P = 1.634 d . TYC 9300-0891-1A , TYC 9300-0891-1B , and TYC 9300-0529-1 have same masses , ages , and initial chemical compositions .
The relatively small 16 % rotation period difference measured by us indicates that all components had similar initial rotation periods and disc lifetimes , and the separation of 157 AU between the component A and the ’ perturber ’ component B ( or vice-versa ) has been sufficiently large to prevent any significant perturbation/shortening of the accretion-disc lifetime .