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

K2-19 (EPIC201505350) is an interesting planetary system in which twotransiting planets with radii ~ 7 $R_{Earth}$ (inner planet b) and ~ 4$R_{Earth}$ (outer planet c) have orbits that are nearly in a 3:2 mean-motionresonance. Here, we present results of ground-based follow-up observations forthe K2-19 planetary system. We have performed high-dispersion spectroscopy andhigh-contrast adaptive-optics imaging of the host star with the HDS and HiCIAOon the Subaru 8.2m telescope. We find that the host star is relatively old (>8Gyr) late G-type star ($T_{eff}$ ~ 5350 K, $M_s$ ~ 0.9 $M_{Sun}$, and $R_{s}$ ~0.9 $R_{Sun}$). We do not find any contaminating faint objects near the hoststar which could be responsible for (or dilute) the transit signals. We havealso conducted transit follow-up photometry for the inner planet with KeplerCamon the FLWO 1.2m telescope, TRAPPISTCAM on the TRAPPIST 0.6m telescope, andMuSCAT on the OAO 1.88m telescope. We confirm the presence of transit-timingvariations, as previously reported by Armstrong and coworkers. We model theobserved transit-timing variations of the inner planet using the synodicchopping formulae given by Deck & Agol (2015). We find two statisticallyindistinguishable solutions for which the period ratios ($P_{c}/P_{b}$) arelocated slightly above and below the exact 3:2 commensurability. Despite thedegeneracy, we derive the orbital period of the inner planet $P_b$ ~ 7.921 daysand the mass of the outer planet $M_c$ ~ 20 $M_{Earth}$. Additional transitphotometry (especially for the outer planet) as well as precise radial-velocitymeasurements would be helpful to break the degeneracy and to determine the massof the inner planet.

Characterization of the K2-19 Multiple-Transiting Planetary System via High-Dispersion Spectroscopy, AO Imaging, and Transit Timing Variations