Probable Spin-Orbit Aligned Super-Earth Planet Candidate KOI-2138.01

Abstract

We use rotational gravity darkening in the disk of \emph{Kepler} star KOI-2138 to show that the orbit of $2.1-R_{\oplus }$ transiting planet candidate KOI-2138.01 has a low projected spin-orbit alignment of $\lambda =1^{\circ }\pm 13$. KOI-2138.01 is just the second super-Earth with a measured spin-orbit alignment after 55 Cancri e, and the first to be aligned. With a 23.55-day orbital period, KOI-2138.01 may represent the tip of a future iceberg of solar-system-like terrestrial planets having intermediate periods and low-inclination circular orbits.

5 pages, 4 figures, published in ApJL 2015 August

References in corpus (13)

• Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e
• Imaging the Surface of Altair
• Stellar Spin-Orbit Misalignment in a Multiplanet System
• Five Planets Orbiting 55 Cancri
• Vega is a rapidly rotating star
• Obliquities of Kepler Stars: Comparison of Single- and Multiple-Transit Systems
• A Misaligned Prograde Orbit for Kepler-13 Ab via Doppler Tomography
• Measurement of Spin-Orbit Misalignment and Nodal Precession for the Planet around Pre-Main-Sequence Star PTFO 8-8695 From Gravity Darkening
• Spin-Orbit Angles of Kepler-13Ab and HAT-P-7b from Gravity-Darkened Transit Light Curves
• Spin-Orbit angle distribution and the origin of (mis)aligned hot Jupiters
• Detecting the spin-orbit misalignment of the super-Earth 55 Cnc e
• A highly inclined orbit for the 110-day period M-dwarf companion KOI-368.01
• Spin-Orbit Alignment For 110-Day-Period KOI368.01 From Gravity Darkening

Cited by in corpus (11)

• Stellar obliquities in exoplanetary systems
• GJ1214: Rotation period, starspots, and uncertainty on the optical slope of the transmission spectrum
• KELT-9 b's Asymmetric TESS Transit Caused by Rapid Stellar Rotation and Spin-Orbit Misalignment
• Spi-OPS: Spitzer and CHEOPS confirm the near-polar orbit of MASCARA-1 b and reveal a hint of dayside reflection
• Two Small Transiting Planets and a Possible Third Body Orbiting HD 106315
• DREAM II. The spin-orbit angle distribution of close-in exoplanets under the lens of tides
• Spin-Orbit Misalignments of Three Jovian Planets via Doppler Tomography
• Gravity-Darkening Analysis of Misaligned Hot Jupiter MASCARA-4 b
• Dealing With $\delta$-Scuti Variables: Transit Light Curve Analysis of Planets Orbiting Rapidly-Rotating, Seismically Active A/F Stars
• Rapid rotators revisited: absolute dimensions of KOI-13
• True spin-orbit obliquities distribution: data-driven confirmation of no clustering of misaligned planets