Josh Peek edited section_Conclusions_In_this_work__.tex  almost 8 years ago

Commit id: 4ca4c6fffab8662785bae3e080671e65839db178

deletions | additions      

       

\section{Conclusions}  In this work we have found that while the H$\epsilor$ H$\epsilon$  line is not as powerful a discriminant between BHB, BS, and MS stars as the H$\gamma$ or H$\delta$ line, it can be used to show that USNO-A0600-15865535 is a BHB star approximately 5.2 kpc from the sun. We demonstrated that this star has clear Calcium H \& K absorption lines at a velocity coincident with Complex WD, and that therefor Complex WD must be closer than 5.2 kpc. We used this fact to rule out the typically assumed model of Complex WD, that is a Complex C-like cloud on the far side of the Galaxy, corotating with disk. Furthermore we investigated an intermediate distance scenario in which the Complex resides at $\sim 5$ kpc and found it difficult to reconcile the fixed LSR velocity of the cloud with the strong gradients implied from both the reflex solar motion and differential Galactic rotation. A "near" scenario, wherein a the complex was ejected from the solar vicinity to a distance of a few kpc seemed the most likely, though it would make the HVC the lowest in altitude known. Future observations toward USNO-A0600-15865535 would enable precise determinations of metallicities using other elements, which would help determine whether a disk-origin for this cloud is likely. Further observations towards closer stars, and across the face of the cloud could give us much more detailed information about the distance and three-dimensional morphology of the cloud, which would also help us understand how the cloud came to be, and how it relates to the accretion and feedback story of the Milky Way.