Context. We previously reported the direct detection of a low-mass companion at a projected separation of 55 ± 2 AU around the B9-type star κ Andromedae. The properties of the system (mass ratio, separation) make it a benchmark for understanding the formation and evolution of gas giant planets and brown dwarfs on wide orbits. Aims. We present new angular differential imaging (ADI) images of the system at 2.146 (K s ), 3.776 (L ), 4.052 (NB_4.05), and 4.78 µm (M ) obtained with Keck/NIRC2 and LBTI/LMIRCam, as well as more accurate near-infrared photometry of the star with the MIMIR instrument. We aim to determine the near-infrared spectral energy distribution of the companion and use it to characterize the object. Methods. We used analysis methods adapted to ADI to extract the companion flux. We compared the photometry of the object to reference young, and old objects and to a set of seven PHOENIX-based atmospheric models of cool objects accounting for the formation of dust. We used evolutionary models to derive mass estimates considering a wide range of plausible initial conditions. Finally, we used dedicated formation models to discuss the possible origin of the companion. Results. We derive a more accurate J = 15.86 ± 0.21, H = 14.95 ± 0.13, K s = 14.32 ± 0.09 mag for κ And b. We detect the companion in all our high-contrast observations. We confirm previous contrasts obtained at K s and L band. We derive NB_4.05 = 13.0 ± 0.2, and M = 13.3 ± 0.3 mag and estimate log 10 (L/L ) = −3.76 ± 0.06. Atmospheric models yield T eff = 1900 +100 −200 K. They do not set any constraint on the surface gravity. "Hotstart" evolutionary models predict masses of 14 +25 −2 M Jup based on the luminosity and temperature estimates, and when considering a conservative age range for the system (30 +120 −10 Myr), "warm-start" evolutionary tracks constrain the mass to M ≥ 10 M Jup . Conclusions. The mass of κ Andromedae b mostly falls in the brown-dwarf regime, owing to remaining uncertainties in age and in mass-luminosity models. According to the formation models, disk instability in a primordial disk may account for the position and a wide range of plausible masses of κ And b.

The recently discovered γ-ray binary 1FGL J1018.6-5856 has a proposed optical/near-infrared (OIR) counterpart 2MASS 10185560-5856459. We present Strömgren photometry of this star to investigate its photometric variability and measure the reddening and distance to the system. We find that the γ-ray binary has E(B − V ) = 1.34 ± 0.04 and d = 5.4 +4.6 −2.1 kpc. . While E(B − V ) is consistent with X-ray observations of the neutral hydrogen column density, the distance is somewhat closer than some previous authors have suggested.

The field of asteroseismology has enjoyed a large swath of data coming from recent missions (e.g., CoRoT, Kepler, K2 ). This wealth of new data has allowed the field to expand beyond the previous limitation of a few extremely bright and evolved stars. Asteroseismology relies on accurate surface measurements for boundary conditions, but the predicted physical parameters in the Kepler Input Catalog (KIC) are unreliable for hot stars. We present stellar parameters of 25 candidate pulsating B star candidates in the Kepler field. We use blue optical spectra to measure the projected rotational velocity (V sin i), effective temperature (T eff ), and surface gravity (log g) using TLUSTY and Kurucz ATLAS9 model atmospheres. We find a large discrepancy between our spectroscopically derived parameters and those derived from photometry in the KIC and Gaia Data Release 2 (DR2). Using spectral energy distributions, we also measure the radii of these stars and later calculate the luminosities and masses. We find the extinctions (A V ) of these stars to be consistent with zero, which is expected for stars of high Galactic latitude.

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