Search Publications
Double-lined Spectroscopic Binaries from the LAMOST Low-resolution Survey
Ting, Yuan-Sen; Liu, Junhui; Zhang, Bo +1 more
We report on a data-driven spectral model that we have developed for the identification of double-lined spectroscopic binary stars (SB2s) in the Large Sky Area Multi-Object fiber Spectroscopic Telescope low-resolution survey (R ∼ 1800). Employing simultaneous fitting with both single-star and binary-star models, we detected over 4800 SB2 candidate…
A survey for variable young stars with small telescopes - VIII. Properties of 1687 Gaia selected members in 21 nearby clusters
Scholz, Aleks; Eislöffel, Jochen; Dvorak, Shawn +60 more
The Hunting Outbursting Young Stars (HOYS) project performs long-term, optical, multifilter, high cadence monitoring of 25 nearby young clusters and star-forming regions. Utilizing Gaia DR3 data, we have identified about 17 000 potential young stellar members in 45 coherent astrometric groups in these fields. Twenty one of them are clear young gro…
Is It Possible to Detect Coronal Mass Ejections on Solar-type Stars through Extreme-ultraviolet Spectral Observations?
Tian, Hui; Yang, Zihao; Xu, Yu +3 more
Stellar coronal mass ejections (CMEs) from host stars are an important factor that affects the habitability of exoplanets. Although their solar counterparts have been well observed for decades, it is still very difficult to find solid evidence of stellar CMEs. Using the spectral line profile asymmetry caused by the Doppler shift of erupting plasma…
Photometric determination of main-sequence binaries with Gaia
Wallace, A. L.
Since its launch in 2013, the Gaia space telescope has provided precise measurements of the positions and magnitudes of over 1 billion stars. This has enabled extensive searches for stellar and substellar companions through astrometric and radial velocity measurements. However, these surveys require a prior knowledge of any unresolved companion af…
AB Dor: Coronal Imaging and Activity Cycles
Pandey, J. C.; Singh, Gurpreet
Using long-term X-ray observations, we present short-term and long-term X-ray variability analysis of the ultrafast rotating active star AB Dor. Flaring events are common in X-ray observations of AB Dor and occupy a substantial portion of the total observation time, averaging at around 57% ± 23%. The flare-free X-ray light curves show rotational m…
First High-resolution Spectroscopy of X-Ray Absorption Lines in the Obscured State of NGC 5548
Gu, Liyi; Kriss, Gerard A.; Mehdipour, Missagh +5 more
Multiwavelength spectroscopy of NGC 5548 revealed remarkable changes due to the presence of an obscuring wind from the accretion disk. This broadened our understanding of obscuration and outflows in active galactic nuclei. Swift monitoring of NGC 5548 shows that over the last 10 yr, the obscuration has gradually declined. This provides a valuable …
An Infrared Census of R Coronae Borealis Stars II—Spectroscopic Classifications and Implications for the Rate of Low-mass White Dwarf Mergers
Soria, Roberto; Clayton, Geoffrey C.; De, Kishalay +18 more
We present results from a systematic infrared (IR) census of R Coronae Borealis (RCB) stars in the Milky Way, using data from the Palomar Gattini IR (PGIR) survey. RCB stars are dusty, erratic variable stars presumably formed from the merger of a He-core and a CO-core white dwarf (WD). PGIR is a 30 cm J-band telescope with a 25 deg2 cam…
Kinematics and Star Formation in the Hub–Filament System G6.55-0.1
Wyrowski, Friedrich; Güsten, Rolf; Ishwara-Chandra, C. H. +2 more
Hub–filament systems (HFSs) being the potential sites of formation of star clusters and high-mass stars, provide a testbed for the current theories that attempt to explain star formation globally. It is thus important to study a large number of HFSs using both intensity and velocity information to constrain these objects better observationally. He…
A Deep Redshift Survey of the Perseus Cluster (A426): Spatial Distribution and Kinematics of Galaxies
Park, Byeong-Gon; Hwang, Narae; Hwang, Ho Seong +3 more
We study the global kinematics of the Perseus galaxy cluster (A426) at redshift z = 0.017 using a large sample of galaxies from our new MMT/Hectospec spectroscopic observation for this cluster. The sample includes 1447 galaxies with measured redshifts within 60' from the cluster center (1148 from this MMT/Hectospec program and 299 from the literat…
New Catalog of Distances to Planetary Nebulae Based on Gaia Parallaxes and Statistical Distances
Peña, M.; Rodríguez, M.; Hernández-Juárez, D.
We have developed a method to determine the most reliable distances for a large group of planetary nebulae. For this purpose, we analyze the distances obtained from Gaia parallaxes and three determinations of statistical distances. The most reliable distance is derived for 2211 objects, and uncertainties for these distances are calculated in a hom…