Publication Date:
2016-10-21
Description:
We present new measurements of the projected spin-orbit angle for six WASP hot Jupiters, four of which are new to the literature (WASP-61, -62, -76, and -78), and two of which are new analyses of previously measured systems using new data (WASP-71, and -79). We use three different models based on two different techniques: radial velocity measurements of the Rossiter–McLaughlin effect, and Doppler tomography. Our comparison of the different models reveals that they produce projected stellar rotation velocities ( v sin I s ) measurements often in disagreement with each other and with estimates obtained from spectral line broadening. The Boué model for the Rossiter–McLaughlin effect consistently underestimates the value of v sin I s compared to the Hirano model. Although v sin I s differed, the effect on was small for our sample, with all three methods producing values in agreement with each other. Using Doppler tomography, we find that WASP-61 b ( $\lambda =4{^{\circ}_{.}}0^{+17.1}_{\,\,\,-18.4}$ ), WASP-71 b ( $\lambda =-1{^{\circ}_{.}}9^{+7.1}_{\,\,\,-7.5}$ ), and WASP-78 b ( = –6 $_{.}^{\circ}$ 4 ± 5.9) are aligned. WASP-62 b ( $\lambda =19{^{\circ}_{.}}4^{+5.1}_{\,\,\,-4.9}$ ) is found to be slightly misaligned, while WASP-79 b ( $\lambda =-95{^{\circ}_{.}}2^{+0.9}_{\,\,\,-1.0}$ ) is confirmed to be strongly misaligned and has a retrograde orbit. We explore a range of possibilities for the orbit of WASP-76 b, finding that the orbit is likely to be strongly misaligned in the positive direction.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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