Astronomy and Astrophysics – Astrophysics – Earth and Planetary Astrophysics
Scientific paper
2011-06-13
Astronomy and Astrophysics
Astrophysics
Earth and Planetary Astrophysics
Accepted for publication in ApJ
Scientific paper
We present precise radial-velocity measurements of WASP-1 and WASP-2 throughout transits of their giant planets. Our goal was to detect the Rossiter-McLaughlin (RM) effect, the anomalous radial velocity observed during eclipses of rotating stars, which can be used to study the obliquities of planet-hosting stars. For WASP-1 a weak signal of a prograde orbit was detected with ~2sigma confidence, and for WASP-2 no signal was detected. The resulting upper bounds on the RM amplitude have different implications for these two systems, because of the contrasting transit geometries and the stellar types. Because WASP-1 is an F7V star, and such stars are typically rapid rotators, the most probable reason for the suppression of the RM effect is that the star is viewed nearly pole-on. This implies the WASP-1 star has a high obliquity with respect to the edge-on planetary orbit. Because WASP-2 is a K1V star, and is expected to be a slow rotator, no firm conclusion can be drawn about the stellar obliquity. Our data and our analysis contradict an earlier claim that WASP-2b has a retrograde orbit, thereby revoking this system's status as an exception to the pattern that cool stars have low obliquities.
Albrecht Simon
Butler Paul R.
Crane Jeffrey D.
Enya Keigo
Fischer Debra
No associations
LandOfFree
Two Upper Limits on the Rossiter-McLaughlin Effect, with Differing Implications: WASP-1 has a High Obliquity and WASP-2 is Indeterminate does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Two Upper Limits on the Rossiter-McLaughlin Effect, with Differing Implications: WASP-1 has a High Obliquity and WASP-2 is Indeterminate, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two Upper Limits on the Rossiter-McLaughlin Effect, with Differing Implications: WASP-1 has a High Obliquity and WASP-2 is Indeterminate will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-112534