Abstract
Small, cool planets represent the typical end-products of planetary
formation. Studying the archi- tectures of these systems, measuring planet
masses and radii, and observing these planets' atmospheres during transit
directly informs theories of planet assembly, migration, and evolution. Here we
report the discovery of three small planets orbiting a bright (Ks = 8.6 mag) M0
dwarf using data collected as part of K2, the new transit survey using the
re-purposed Kepler spacecraft. Stellar spectroscopy and K2 photometry indicate
that the system hosts three transiting planets with radii 1.5-2.1 R\_Earth,
straddling the transition region between rocky and increasingly
volatile-dominated compositions. With orbital periods of 10-45 days the planets
receive just 1.5-10x the flux incident on Earth, making these some of the
coolest small planets known orbiting a nearby star; planet d is located near
the inner edge of the system's habitable zone. The bright, low-mass star makes
this system an excellent laboratory to determine the planets' masses via
Doppler spectroscopy and to constrain their atmospheric compositions via
transit spectroscopy. This discovery demonstrates the power of K2 and future
space-based transit searches to find many fascinating objects of interest.
Users
Please
log in to take part in the discussion (add own reviews or comments).