Search for: All records

Abstract In order to study exoplanets, a comprehensive characterisation of the fundamental properties of the host stars – such as angular diameter, temperature, luminosity, and age, is essential, as the formation and evolution of exoplanets are directly influenced by the host stars at various points in time. In this paper, we present interferometric observations taken of directly imaged planet host 51 Eridani at the CHARA Array. We measure the limb-darkened angular diameter of 51 Eridani to be$$\theta_\mathrm{LD} = 0.450\pm 0.006$$mas and combining with the Gaia zero-point corrected parallax, we get a stellar radius of$$1.45 \pm 0.02$$R$$_{\odot}$$. We use the PARSEC isochrones to estimate an age of$$23.2^{+1.7}_{-2.0}$$Myr and a mass of$$1.550^{+0.006}_{-0.005}$$M$$_{\odot}$$. The age and mass agree well with values in the literature, determined through a variety of methods ranging from dynamical age trace-backs to lithium depletion boundary methods. We derive a mass of$$4.1\pm0.4$$M$$_\mathrm{Jup}$$for 51 Eri b using the Sonora Bobcat models, which further supports the possibility of 51 Eri b forming under either the hot-start formation model or the warm-start formation model. 

Enhancement of the σ–hole on the halogen atom of aryl halides due to perfluorination of the ring is demonstrated by use of the Extended Townes−Dailey (ETD) model coupled to a Natural Atomic Orbital Bond analysis on two perfluorinated aryl halides (C 6 F 5 Cl and C 6 F 5 Br) and their hydrogenated counterparts. The ETD analysis, which quantifies the halogen p-orbitals populations, relies on the nuclear quadrupole coupling constants which in this work are accurately determined experimentally from the rotational spectra. The rotational spectra investigated by Fourier-transform microwave spectroscopy performed in supersonic expansion are reported for the parent species of C 6 F 5 Cl and C 6 F 5 Br and their 13 C, 37 Cl or 81 Br substituted isotopologues observed in natural abundance. The experimentally determined rotational constants combined with theoretical data at the MP2/aug-cc-pVTZ level provide precise structural information from which an elongation of the ring along its symmetry axis due to perfluorination is proved.