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IRAS 09002-4732: A Laboratory for the Formation of Rich Stellar Clusters
Garmire, Gordon P.; Feigelson, Eric D.; Broos, Patrick S. +2 more
IRAS 09002-4732 is a poorly studied embedded cluster of stars in the Vela Molecular Ridge at a distance of 1.7 kpc. Deep observations with the Chandra X-ray Observatory, combined with existing optical and infrared surveys, produce a catalog of 441 probable pre-main-sequence members of the region. The stellar spatial distribution has two components…
Two Circumstellar Nebulae Discovered with the Wide-field Infrared Survey Explore and Their Massive Central Stars
Grebel, Eva K.; Castro, Norberto; Gvaramadze, Vasilii V. +1 more
We report the discovery of two mid-infrared nebulae in the northern hemisphere with the Wide-field Infrared Survey Explorer and the results of optical spectroscopy of their central stars, BD+60° 2668 (composed of two components, separated from each other by ≈3 arcsec) and ALS 19653, with the Calar Alto 3.5 m telescope and the Southern African Larg…
Observations of Red Giants with Suspected Massive Companions
Tokovinin, Andrei; Makarov, Valeri V.
Motivated by the existence of binary systems where a stellar-mass black hole is bound to a normal star, we selected four red giants with large radial velocity (RV) variation from the survey of Space Interferometry Mission (SIM) grid stars and monitored their RVs for several months. None turned out to contain a massive companion above 2.5 solar mas…
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 …