ANALYSIS OF SPIN-ORBIT ALIGNMENT IN THE WASP-32, WASP-38, AND HAT-P-27/WASP-40 SYSTEMS

We present measurements of the spin-orbit alignment angle,., for the hot Jupiter systems WASP-32, WASP-38, and HAT-P-27/WASP-40, based on data obtained using the HARPS spectrograph. We analyze the Rossiter-McLaughlin effect for all three systems and also carry out Doppler tomography for WASP-32 and WASP-38. We find that WASP-32 (T-eff = 6140(-100)(+90) K) is aligned, with an alignment angle of lambda = 10 degrees.5(-6.5)(+6.4) obtained through tomography, and that WASP-38 (T-eff = 6180(-60)(+40) K) is also aligned, with tomographic analysis yielding lambda = 7 degrees.5(-6.1)(+4.7). The latter result provides an order-of-magnitude improvement in the uncertainty in lambda compared to the previous analysis of Simpson et al. We are only able to loosely constrain the angle for HAT-P-27/WASP-40 (T-eff = 5190(-170)(+160) K) to lambda = 24 degrees.2(-44.5)(+76.0), owing to the poor signal-to-noise ratio of our data. We consider this result a non-detection under a slightly updated version of the alignment test of Brown et al. We place our results in the context of the full sample of spin-orbit alignment measurements, finding that they provide further support for previously established trends.