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A Photometric and Astrometric Study of the Open Clusters NGC 1664 and NGC 6939
Bilir, Selçuk; Yontan, Talar; Paunzen, Ernst +5 more
This study calculated astrophysical parameters, as well as kinematic and galactic orbital parameters, of the open clusters NGC 1664 and NGC 6939. The work is based on CCD ultraviolet, blue, and visual (UBV) and Gaia photometric and astrometric data from ground- and space-based observations. Considering Gaia Early Data Release 3 (EDR3) astrometric …
New CCD Astrometric Observations of Himalia Using Gaia DR2 in 2015-2021
Chen, Y.; Vienne, A.; Lin, F. R. +4 more
The long arc and high-quality astrometric measurements of outer irregular satellites are prerequisites for improving their orbital theories and increasing the precision of their ephemerides. In order to obtain good astrometric positions of Himalia, the largest irregular satellite of Jupiter, we have processed and reduced 911 ground-based CCD frame…
LkHα 225 (V1318 Cyg) South in Outburst
Rodriguez, Antonio C.; Hillenbrand, Lynne A.; Reipurth, Bo +5 more
Magakian et al. called attention to the current bright state of LkHα 225 South, a well-known highly embedded, intermediate-mass young stellar object that over the past two decades has brightened visually from >20 m to <13 m . We present recent optical photometric monitoring showing colorless, nonsinusoidal, periodic br…
TOI-1696 and TOI-2136: Constraining the Masses of Two Mini-Neptunes with the Habitable-Zone Planet Finder
Kobulnicky, Henry A.; Cochran, William D.; Endl, Michael +29 more
We present the validation of two planets orbiting M dwarfs, TOI-1696b and TOI-2136b. Both planets are mini-Neptunes orbiting nearby stars, making them promising prospects for atmospheric characterization with the James Webb Space Telescope (JWST). We validated the planetary nature of both candidates using high-contrast imaging, ground-based photom…
A Search for Predicted Astrometric Microlensing Events by Nearby Brown Dwarfs
Lu, Jessica R.; McGill, Peter; Leauthaud, Alexie +3 more
Gravitational microlensing has the potential to provide direct gravitational masses of single, free-floating brown dwarfs, independent of evolutionary and atmospheric models. The proper motions and parallaxes of nearby brown dwarfs can be used to predict close future alignments with distant background stars that cause a microlensing event. Targete…
Searching for Variable Stars in the Open Cluster NGC 2355 and Its Surrounding Region
Hu, Qingshun; Zhang, Yu; Qin, Mingfeng +4 more
We have investigated the variable stars in the field surrounding NGC 2355 based on the time-series photometric observation data. More than 3000 CCD frames were obtained in the V band spread over 13 nights with the Nanshan One-meter Wide-field Telescope. We have detected 88 variable stars, containing 72 new variable stars and 16 known variable star…
The Emission Spectrum of the Hot Jupiter WASP-79b from HST/WFC3
Mikal-Evans, Thomas; Sing, David K.; López-Morales, Mercedes +12 more
Here we present a thermal emission spectrum of WASP-79b, obtained via Hubble Space Telescope Wide Field Camera 3 G141 observations as part of the PanCET program. As we did not observe the ingress or egress of WASP-79b's secondary eclipse, we consider two scenarios: a fixed mid-eclipse time based on the expected occurrence time, and a mid-eclipse t…
CLusters in the UV as EngineS (CLUES). I. Survey Presentation and FUV Spectral Analysis of the Stellar Light
Hayes, Matthew; Chisholm, John; Östlin, Göran +18 more
The CLusters in the Uv as EngineS (CLUES) survey is a Cosmic Origins Spectrograph (COS) campaign aimed at acquiring the 1130-1770 Å rest-frame spectroscopy of very young (<20 Myr) and massive (>104 M ⊙) star clusters in galaxies that are part of the Hubble treasury program Legacy ExtraGalactic UV Survey. In this first p…
The Emptiness Inside: Finding Gaps, Valleys, and Lacunae with Geometric Data Analysis
Hogg, David W.; Peek, Joshua E. G.; Hunt, Jason A. S. +2 more
Discoveries of gaps in data have been important in astrophysics. For example, there are kinematic gaps opened by resonances in dynamical systems, or exoplanets of a certain radius that are empirically rare. A gap in a data set is a kind of anomaly, but in an unusual sense: instead of being a single outlier data point, situated far from other data …
A Close-in Puffy Neptune with Hidden Friends: The Enigma of TOI 620
Bieryla, Allyson; Latham, David W.; Quinn, Samuel N. +82 more
We present the validation of a transiting low-density exoplanet orbiting the M2.5 dwarf TOI 620 discovered by the NASA Transiting Exoplanet Survey Satellite (TESS) mission. We utilize photometric data from both TESS and ground-based follow-up observations to validate the ephemerides of the 5.09 day transiting signal and vet false-positive scenario…