English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The Rossiter-McLaughlin effect is the principal method of determining thesky-projected spin--orbit angle ($\beta$) of transiting planets. Taking theexample of the recently discovered TRAPPIST-1 system, we explore how ultracooldwarfs facilitate the measurement of the spin--orbit angle for Earth-sizedplanets by creating an effect that can be an order of magnitude more ample thanthe Doppler reflex motion caused by the planet if the star is undergoing rapidrotation. In TRAPPIST-1's case we expect the semi-amplitudes of theRossiter-McLaughlin effect to be $40-50$ m/s for the known transiting planets.Accounting for stellar jitter expected for ultracool dwarfs, instrumentalnoise, and assuming radial velocity precisions both demonstrated andanticipated for upcoming near-infrared spectrographs, we quantify theobservational effort required to measure the planets' masses and spin--orbitangles. We conclude that if the planetary system is well-aligned then $\beta$can be measured to a precision of $\lesssim 10^{\circ}$ if the spectrograph isstable at the level of 2 m/s. We also investigate the measure of $\Delta\beta$, the mutual inclination, when multiple transiting planets are present inthe system. Lastly, we note that the rapid rotation rate of many late M-dwarfswill amplify the Rossiter-McLaughlin signal to the point where variations inthe chromatic Rossiter-McLaughlin effect from atmospheric absorbers should bedetectable.

Prospects for detecting the Rossiter-McLaughlin effect of Earth-like planets: the test case of TRAPPIST-1b and c