Search Publications
Precise Ages of Field Stars from White Dwarf Companions in Gaia DR2
Qiu, Dan; Tian, Hai-Jun; Liu, Gao-Chao +5 more
We analyze 4050 wide binary star systems involving a white dwarf (WD) and usually a main-sequence (MS) star, drawn from the large sample assembled by Tian et al. Using the modeling code BASE-9, we determine the system's ages, the WD progenitors' zero-age MS masses, the extinction values (AV), and the distance moduli. Discarding the case…
Exploring the Stellar Rotation of Early-type Stars in the LAMOST Medium-resolution Survey. I. Catalog
Deng, Licai; de Grijs, Richard; Liu, Chao +3 more
We derive stellar parameters and abundances ("stellar labels") of 40,034 late-B and A-type main-sequence stars extracted from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope Medium Resolution Survey (LAMOST-MRS). The primary selection of our early-type sample was obtained from LAMOST Data Release 7 based on spectral-line indices. We …
Surveying the Bright Stars by Optical Interferometry. III. A Magnitude-limited Multiplicity Survey of Classical Be Stars
Hutter, D. J.; Tycner, C.; Zavala, R. T. +3 more
We present the results of a multiplicity survey for a magnitude-limited sample of 31 classical Be stars conducted with the Navy Precision Optical Interferometer and the Mark III Stellar Interferometer. The interferometric observations were used to detect companions in 10 previously known binary systems. For two of these sources (66 Oph and β Cep) …
An ACA Survey of [C I] 3P1-3P0, CO J = 4 - 3, and Dust Continuum in Nearby U/LIRGs
Ho, Luis C.; Bolatto, Alberto D.; Tadaki, Ken-ichi +11 more
We present the results of surveying [C I] 3P1-3P0, 12CO J = 4 - 3, and 630 µm dust continuum emission for 36 nearby ultra/luminous infrared galaxies (U/LIRGs) using the Band 8 receiver mounted on the Atacama Compact Array of the Atacama Large Millimeter/submillimeter Array. We describe t…
Numerical Modeling of Latitudinal Gradients for Galactic Cosmic-Ray Protons during Solar Minima: Comparing with Ulysses Observations
Qin, Gang; Shen, Zhenning; Zuo, Pingbing +2 more
The latitudinal gradients of galactic cosmic-ray (GCR) protons measured by Ulysses during two successive minima provide a unique opportunity to study the modulation effects in polar regions of the heliosphere. In this work, a GCR modulation model based on numerically solving the Parker transport equation is used to study the latitudinal distributi…
Revisiting the Fundamental Parameters of 49 New Star Clusters in Gaia DR2
Li, Zhongmu; Chen, Jing; Deng, Yangyang
Reliable fundamental parameters of star clusters such as distance modulus, metallicity, age, extinction, and binary fraction are of key importance for astrophysical studies. Although a lot of new star clusters were identified from the data of, e.g., Gaia Data Release 2 (Gaia DR2), the fundamental parameters of many clusters were not determined rel…
Magnetohydrodynamic Modeling of the Solar Corona with an Effective Implicit Strategy
Shen, Fang; Feng, Xueshang; Xiang, Changqing +4 more
In this paper, we design an effective and robust model to solve the 3D single-fluid solar wind plasma magnetohydrodynamics (MHD) problem of low plasma β. This MHD model is formulated on a six-component composite grid system free of polar singularities. The computational domain ranges from the solar surface to the super-Alfvénic region. As common t…
WawHelioGlow: A Model of the Heliospheric Backscatter Glow. I. Model Definition
Bzowski, M.; Kubiak, M. A.; Kowalska-Leszczynska, I. +1 more
The helioglow is the fluorescence of interstellar atoms inside the heliosphere, where they are excited by the solar EUV emission. So far, the helioglow of interstellar H and He has been detected. The helioglow features a characteristic distribution in the sky, which can be used to derive the properties of both interstellar neutral (ISN) gas and th…
The Extinction and Distance of the MBM Molecular Clouds at High Galactic Latitude
Ren, Yi; Jiang, Biwei; Zhao, He +1 more
Based on the accurate color excess {E}_{{{\rm{G}}}_{\mathrm{BP}},{{\rm{G}}}_{\mathrm{RP}}}$ of more than 4 million stars and the {E}_{\mathrm{NUV},{{\rm{G}}}_{\mathrm{BP}}}$ of more than 1 million stars from Sun et al., the distance and extinction of the molecular clouds (MCs) in the Magnani-Blitz-Mundy catalog at ∣b∣ > 20° are studied in combi…
Quiet-Sun Mg II h and k Line Profiles Derived from IRIS Full-Sun Mosaics. I. Reference Profiles and Center-to-limb Variation
Heinzel, Petr; Gunár, Stanislav; Koza, Július +2 more
We derived high-precision reference profiles of the Mg II h and k lines that represent the quiet Sun during a minimum of the solar activity. To do so, we used the broad catalog of full-Sun mosaics obtained by the Interface Region Imaging Spectrograph (IRIS). To minimize the influence of the local variations due to the on-disk solar features and to…