TY - JOUR
T1 - DISCOVERY and VALIDATION of A HIGH-DENSITY SUB-NEPTUNE from the K2 MISSION
AU - Espinoza, Néstor
AU - Brahm, Rafael
AU - Jordán, Andrés
AU - Jenkins, James S.
AU - Rojas, Felipe
AU - Jofré, Paula
AU - Mädler, Thomas
AU - Rabus, Markus
AU - Chanamé, Julio
AU - Pantoja, Blake
AU - Soto, Maritza G.
AU - Morzinski, Katie M.
AU - Males, Jared R.
AU - Ward-Duong, Kimberly
AU - Close, Laird M.
N1 - Publisher Copyright:
© 2016. The American Astronomical Society. All rights reserved.
PY - 2016/10/10
Y1 - 2016/10/10
N2 - We report the discovery of K2-56b, a high-density sub-Neptune exoplanet, made using photometry from Campaign 4 of the two-wheeled Kepler (K2) mission, ground-based radial velocity (RV) follow-up from HARPS and high-resolution lucky and adaptive optics imaging obtained using AstraLux and MagAO, respectively. The host star is a bright (V = 11.04, K s = 9.37), slightly metal-poor ([Fe/H] = -0.15 0.05 dex) solar analogue located at pc from Earth, for which we find a radius of and a mass of . A joint analysis of the K2 photometry and HARPS RVs reveal that the planet is in a ≈42 day orbit around its host star, has a radius of , and a mass of . Although the data at hand put the planet in the region of the mass-radius diagram where we could expect planets with a pure rock (i.e., magnesium silicate) composition using two-layer models (i.e., between rock/iron and rock/ice compositions), we discuss more realistic three-layer composition models which can explain the high density of the discovered exoplanet. The fact that the planet lies in the boundary between "possibly rocky" and "non-rocky" exoplanets makes it an interesting planet for future RV follow-up.
AB - We report the discovery of K2-56b, a high-density sub-Neptune exoplanet, made using photometry from Campaign 4 of the two-wheeled Kepler (K2) mission, ground-based radial velocity (RV) follow-up from HARPS and high-resolution lucky and adaptive optics imaging obtained using AstraLux and MagAO, respectively. The host star is a bright (V = 11.04, K s = 9.37), slightly metal-poor ([Fe/H] = -0.15 0.05 dex) solar analogue located at pc from Earth, for which we find a radius of and a mass of . A joint analysis of the K2 photometry and HARPS RVs reveal that the planet is in a ≈42 day orbit around its host star, has a radius of , and a mass of . Although the data at hand put the planet in the region of the mass-radius diagram where we could expect planets with a pure rock (i.e., magnesium silicate) composition using two-layer models (i.e., between rock/iron and rock/ice compositions), we discuss more realistic three-layer composition models which can explain the high density of the discovered exoplanet. The fact that the planet lies in the boundary between "possibly rocky" and "non-rocky" exoplanets makes it an interesting planet for future RV follow-up.
KW - composition
KW - detection
KW - fundamental parameters
KW - planets and satellites
KW - planets and satellites
KW - planets and satellites
KW - planets and satellites
KW - terrestrial planets
UR - https://www.scopus.com/pages/publications/84991107480
U2 - 10.3847/0004-637X/830/1/43
DO - 10.3847/0004-637X/830/1/43
M3 - Article
AN - SCOPUS:84991107480
SN - 0004-637X
VL - 830
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 43
ER -