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A Deep Study of an Intermediate-age Open Cluster SAI 35 (Juchert 20) Using Ground-based Imaging and Gaia EDR3 Astrometry
Bisht, D.; Rangwal, Geeta; Yadav, R. K. S. +4 more
We present a CCD UBVI photometric study of poorly studied intermediate-age open cluster SAI 35 (Juchert 20) for the first time. To accomplish this study, we also used LAMOST DR5, Two Micron All Sky Survey, and Gaia EDR3 databases. We identified 214 most probable cluster members with membership probability higher than 50%. The mean proper motion of…
Short-period Variability in the Globular Cluster NGC 419 and the SMC Field
Martínez-Vázquez, C. E.; Vivas, A. K.; Salinas, R.
Delta Scuti (δ Sct) stars have been extensively studied in our Galaxy but far less in extragalactic systems. Here we study the population of δ Sct variables in NGC 419, an intermediate-age globular cluster of the Small Magellanic Cloud (SMC), using g, r, and i Gemini-S/Gemini Multi-Object Spectrograph (GMOS) time-series observations. Our goal is t…
Chemical Compositions of Red Giant Stars from Habitable Zone Planet Finder Spectroscopy
Mahadevan, Suvrath; Terrien, Ryan; Lind, Karin +15 more
We have used the Habitable Zone Planet Finder (HPF) to gather high-resolution, high signal-to-noise near-infrared spectra of 13 field red horizontal branch (RHB) stars, one open cluster giant, and one very metal-poor halo red giant. The HPF spectra cover the 0.81-1.28 µm wavelength range of the zyJ bands, partially filling the gap between th…
Linearized Field Deblending: Point-spread Function Photometry for Impatient Astronomers
Luger, Rodrigo; Hedges, Christina; Barentsen, Geert +2 more
NASA's Kepler, K2, and TESS missions employ simple aperture photometry to derive time-series photometry, where an aperture is estimated for each star, and pixels containing each star are summed to create a single light curve. This method is simple, but in crowded fields, the derived time series can be highly contaminated. The alternate method of f…
New Positions of Triton Based on Gaia DR2 and New Image-processing Methods
Zhang, H. Y.; Yan, D.; Qiao, R. C. +2 more
The large time span and precise observational data of natural satellites is of great significance for updating their ephemerides and studying their dynamic characteristics. With the help of the new image-processing methods and the Gaia DR2 catalog, all CCD images of Triton taken with the 1.56 m telescope of Shanghai Astronomical Observatory during…
Hot Degenerates in the MCT Survey. III. A Sample of White Dwarf Stars in the Southern Hemisphere
Kepler, S. O.; Fontaine, G.; Bergeron, P. +7 more
We present optical spectra of 144 white dwarfs detected in the Montreal-Cambridge-Tololo colorimetric survey, including 120 DA, 12 DB, 4 DO, 1 DQ, and 7 DC stars. We also perform a model atmosphere analysis of all objects in our sample using the so-called spectroscopic technique, or the photometric technique in the case of DC white dwarfs. The mai…
Modeling Stellar Abundance Patterns Resulting from the Addition of Earth-like Planetary Material
Cowley, Charles R.; Bord, Donald J.; Yüce, Kutluay
We model the observed precision differential abundance patterns of three G-type dwarfs, assuming a mass of planetary or disk material was added to or subtracted from the atmosphere of the star. The two-parameter model is fit by linear regression. The stellar abundance patterns are corrected for Galactic chemical evolution (GCE). The differential a…
Searching For Transiting Planets Around Halo Stars. I. Sample Selection and Validation
Zinn, Joel C.; Johnson, Jennifer A.; Wang, Ji +3 more
By measuring the elemental abundances of a star, we can gain insight into the composition of its initial gas cloud-the formation site of the star and its planets. Planet formation requires metals, the availability of which is determined by the elemental abundance. In the case where metals are extremely deficient, planet formation can be stifled. T…
Quest for the Upcoming Periastron Passage of an Episodic Dust Maker and Particle-accelerating Colliding-wind Binary: WR 125
Pandey, J. C.; Pandey, S. B.; Sharma, Saurabh +4 more
We have carried out a long-term infrared and X-ray investigation of the colliding-wind binary WR 125 (WC7 + O9III). The source was monitored using AstroSat Soft X-ray Telescope and the Tata Institute of Fundamental Research Near Infrared Imaging Camera-II mounted at the back of 3.6 m Devasthal Optical Telescope. WR 125 appeared brighter in the nea…
Characterizing the X-Ray Emission of Intermediate-mass Pre-main-sequence Stars
Binder, Breanna A.; Townsley, Leisa K.; Broos, Patrick S. +2 more
We use X-ray and infrared observations to study the properties of three classes of young stars in the Carina Nebula: intermediate-mass (2-5 M⊙) pre-main-sequence stars (IMPS; i.e., intermediate-mass T Tauri stars), late-B and A stars on the zero-age main sequence (AB), and lower-mass T Tauri stars (TTS). We divide our sources among thes…