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A New Mass Determination of (349) Dembowska with Close Encounters
Fu, Yanning; Yuan, Ye; Li, Fan
(349) Dembowska is a big R-type main-belt asteroid. A new and more precise determination of its mass, M, is presented. The high precision is achieved, in particular, using our generally applied criterion of selecting model parameters. This criterion takes into account the sensitivity to M of the available observables, i.e., the position of another…
OGLE-2015-BLG-1649Lb: A Gas Giant Planet around a Low-mass Dwarf
Bennett, D. P.; Soszyński, I.; Udalski, A. +70 more
We report the discovery of an exoplanet from the analysis of the gravitational microlensing event OGLE-2015-BLG-1649 that challenges the core accretion model of planet formation and appears to support the disk instability model. The planet/host-star mass ratio is q = 7.2 × 10-3 and the projected separation normalized to the angular Eins…
Solar Neighborhood Kinematics from Gaia -LAMOST Dwarf Stars
Zhu, Z.; Liu, J. -C.; Ding, P. -J.
We use high-precision kinematic data from Gaia data release 2 (DR2) and spectroscopic data from Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) data release 5 (DR5) to explore the kinematics of solar neighborhood dwarf stars in the northern and southern sides of the Galactic plane. The metallicity range of the sampled stars is -…
HD 126516: A Triple System Containing a Short-period Eclipsing Binary
Henry, Gregory W.; Fekel, Francis C.; Sowell, James R.
From numerous radial velocities as well as Johnson B and V differential photoelectric photometry, we have determined the orbital elements and other properties of the single-lined triple system HD 126516. This system consists of a narrow-lined F5 V star and an unseen M dwarf companion in a 2.1241 day circular orbit. The small, low-mass secondary pr…
A Spectroscopic Analysis of the Hyades Cool Giants
Gray, David F.; Martinez, A.
High-resolution spectroscopic observations of the four cool giants in the Hyades cluster, taken at the Elginfield Observatory, are analyzed. The velocity of γ Tau between 2002 and 2009 is constant to a few m s-1 small variations, compatible with the planetary orbit, are seen for ɛ Tau. The primary-to-secondary mass ratio of θ 1
Lunar Occultations with Aqueye+ and Iqueye
Naletto, Giampiero; Burtovoi, Aleksandr; Zampieri, Luca +8 more
We report the first-time use of the Aqueye+ and Iqueye instruments to record lunar occultation events. High time resolution recordings in different filters have been acquired for several occultations taken from 2016 January through 2018 January with Aqueye+ at the Copernicus telescope and Iqueye at the Galileo telescope in Asiago, Italy. Light cur…
A Correction for GALEX Spectroscopic UV Flux Distributions from Comparisons with CALSPEC and IUE
Bianchi, Luciana; Bohlin, Ralph C.
The CALSPEC database of absolute spectral energy distributions (SEDs) from the Hubble Space Telescope is based on pure hydrogen model atmosphere calculations for three unreddened white dwarf stars and represents the current UV flux calibration standard with a precision approaching 1% for well observed stars. Following our previous work to correct …
CCD Measurements of Double and Multiple Stars at ASV and NAO Rozhen in 2017 and 2018
Cvetković, Zorica; Pavlović, Rade; Boeva, Svetlana
We give the results of CCD observations for 789 double or multiple stars obtained during 2017 and 2018. These observations were carried out at both the Serbian Astronomical Station on the mountain of Vidojevica (ASV) and the Bulgarian National Astronomical Observatory at Rozhen (NAOR). They were performed using three telescopes, the 1.4 and 0.6 m …
Probing the Hill Sphere of (486958) 2014 MU69. II. Hubble Space Telescope Fine Guidance Sensors Observations during the 2018 August 4 Stellar Occultation
Stern, S. Alan; Spencer, John R.; Buie, Marc W. +6 more
We observed the 2018 August 4 stellar occultation by the Kuiper Belt object (486958) 2014 MU69, the first close flyby target of the extended New Horizons mission. Rather than capture a solid-body occultation by the KBO itself, our program aimed to constrain the opacity of rings, moons, or other debris in the nearby environment. We used …
Validating the C I 5052.17 Å/Mg II 4481 Å Equivalent Width Ratio as a Diagnostic for F-type Lambda Boo Stars
Cheng, Kwang-Ping; Tarbell, Erik S.; Giacinto, Anthony J. +5 more
The Lambda Boo-type stars are chemically peculiar stars with deficiencies of iron-peak elements but near-solar C, N, O, and S abundances. Since the prototype Lambda Boötis was first reported as peculiar, this group has been expanded from a small group of early A-type stars to a larger group of late B to early F-type dwarfs. Although a detailed abu…