Search Publications
Orbital parameters for an ELM white dwarf with a white dwarf companion: LAMOST J033847.06+413424.2
Huang, Xin; Chen, Xuefei; Li, Zhenwei +13 more
Double white dwarf systems are of great astrophysical importance in the field of gravitational wave and Type Ia supernova. While the binary fraction of CO core white dwarf is about a few per cents, the extremely low mass white dwarfs are all thought to be within binary systems. In this work, we report the orbital solution of a double degenerate sy…
The source of unusual coronal upflows with photospheric abundance in a solar active region
Barczynski, K.; Peter, H.; Zhukov, A. N. +21 more
Context. Upflows in the corona are of importance, as they may contribute to the solar wind. There has been considerable interest in upflows from active regions (ARs). The coronal upflows that are seen at the edges of active regions have coronal elemental composition and can contribute to the slow solar wind. The sources of the upflows have been ch…
Polycyclic aromatic hydrocarbon emission model in photodissociation regions - II. Application to the polycyclic aromatic hydrocarbon and fullerene emission in NGC 7023
Cami, Jan; Tielens, A. G. G. M.; Peeters, Els +1 more
We present a charge distribution-based emission model that calculates the infrared spectrum of fullerenes (C60). Analysis of the modelled spectrum of C60 in various charge states shows that the relative intensity of the features in the 5-10 µm versus 15-20 µm can be used to probe the C60 charge state in…
The Phase Response of a Rough Rectangular Facet for Radar Sounder Simulations of Both Coherent and Incoherent Scattering
Gerekos, C.; Haynes, M. S.; Schroeder, D. M. +1 more
With radar sounders, coherent backscattering simulations from global planetary digital elevation models (DEMs) typically display a deficit in diffuse clutter, which is mainly due to the implicit assumption that roughness at scales below the resolution of the DEM is absent. Indeed, while polynomial approximations of the phase evolution across the f…
A Search for Exoplanets around Northern Circumpolar Stars. IX. A Multi-Period Analysis of the M Giant HD 135438
Lee, Byeong-Cheol; Park, Myeong-Gu; Lim, Beomdu +4 more
It is difficult to distinguish the pure signal produced by an orbiting planetary companion around giant stars from other possible sources, such as stellar spots, pulsations, or certain activities. Since 2003, we have obtained radial (RV) data from evolved stars using the high-resolution, fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) …
Astrometry with PRAIA
Assafin, M.
PRAIA - Package for the Reduction of Astronomical Images Automatically - is a suite of astrometric and photometric tasks designed to cope with huge amounts of heterogeneous observations with fast processing, no human intervention, minimum parameterization and yet maximum possible accuracy and precision. It is the main tool used to analyse astronom…
The radial profile of dust grain size in the protoplanetary disc of DS Tau
Wang, Hongchi; Ma, Yuehui; Liu, Yao +2 more
How do dust grains in protoplanetary discs overcome rapid radial drift and grow from micron size particles to planets is not well understood. The key is to search for evidence of dust accumulation and growth as a function of radius in the disc. We investigate the radial profile of grain size in the DS Tau disc by fitting multiband ALMA observation…
Chemical Compositions Of Red Giant Stars in the Old Open Cluster NGC 7789
Pilachowski, Catherine A.; Afşar, Melike; Sneden, Christopher +1 more
We have gathered optical-region spectra, derived model atmosphere parameters, and computed elemental abundances for 15 red giant stars in the open cluster NGC 7789. We focus on the light element group CNOLi that provides clues to evolutionary changes associated with internal fusion events and chemical mixing. We confirm and extend an early report …
New SB1s with Spectroscopic Orbits from LAMOST-LRS
Wang, Xiaoli; Fu, Yanning; Yuan, Ye +2 more
The LAMOST Low-Resolution Spectroscopic (LAMOST-LRS) Survey provides radial velocities of 10 million stars. These observations can be used to identify new single-lined spectroscopic binaries (SB1s) with their preliminary spectroscopic orbits. First, we perform a statistical χ 2 test on a subsample of LAMOST-LRS stars with velocity obser…
Secular light curves of comets 60P/Tsuchinshan 2 and 62P/Tsuchinshan 1
Li, Juncen; Shi, Jianchun; Ma, Yuehua
The activity of Jupiter family comets, 60P/Tsuchinshan 2 and 62P/Tsuchinshan 1, is analysed by creating their Secular light curves (SLCs). We collected 850 observations in apparitions 1995, 2005, 2012, and 2018 for 60P/Tsuchinshan 2 and 471 observations in apparitions 1998, 2004, and 2017 for 62P/Tsuchinshan 1. We obtained the main activity parame…