Search Publications
Utilizing Photometry from Multiple Sources to Mitigate Stellar Variability in Precise Radial Velocities: A Case Study of Kepler-21
Wright, Jason T.; Logsdon, Sarah E.; Luque, Rafael +26 more
We present a new analysis of Kepler-21, the brightest (V = 8.5) Kepler system with a known transiting exoplanet, Kepler-21 b. Kepler-21 b is a radius valley planet (R = 1.6 ± 0.2R ⊕) with an Earth-like composition (8.38 ± 1.62 g cm–3), though its mass and radius fall in the regime of possible "water worlds." We utilize new Ke…
Variability in Protoplanetary Nebulae. X. Multiyear Periods as an Indicator of Potential Binaries
Lu, Wenxian; Hrivnak, Bruce J.; Henson, Gary +1 more
New observations are presented of four evolved objects that display long, multiyear variations in their light curves. These are interpreted as good evidence of their binary nature, with the modulation caused by the barycenter motion of the evolved star resulting in a periodic obscuration by a circumbinary disk. Although protoplanetary nebulae (PPN…
Flaring Activity for Low-mass Stars in the β Pictoris Moving Group
Schlieder, Joshua E.; Komacek, Thaddeus D.; Ealy, Jordan N. +1 more
Stellar flares from K and M dwarfs release panchromatic radiation characterized by a significantly higher brightness temperature (∼9–20 kK) than the star. The increased frequency of magnetic activity on young low-mass stars results in the energy released during flaring events becoming a notable contributor to the radiation environment. This study …
Measuring Fiber Positioning Accuracy and Throughput with Fiber Dithering for the Dark Energy Spectroscopic Instrument
Moustakas, J.; Brooks, D.; Doel, P. +48 more
Highly multiplexed, fiber-fed spectroscopy is enabling surveys of millions of stars and galaxies. The performance of these surveys depends on accurately positioning fibers in the focal plane to capture target light. We describe a technique to measure the positioning accuracy of fibers by dithering fibers slightly around their ideal locations. This…
Cluster Formation in a Filamentary Cloud: The Case of the Stellar Cluster NGC 2316
Sharma, Saurabh; Panwar, Neelam; Verma, Aayushi +7 more
We present a multiwavelength analysis of the star cluster NGC 2316 and its surroundings. We estimated the physical parameters of the NGC 2316 cluster, including its shape (elongated), size (R cluster = 0.4 pc), distance (1.3 ± 0.3 kpc), and minimum reddening (A V = 1.55 mag). We discovered two massive stars (B2.0V-B1.5V, ag…
Overview Results of JWST Observations of Star-forming Clusters in the Extreme Outer Galaxy
Kobayashi, Naoto; Koch, Patrick M.; Lau, Ryan M. +4 more
The extreme outer Galaxy (EOG), which we define as the region of the Milky Way with a galactocentric radius of more than 18 kpc, provides an excellent opportunity to study star formation in an environment significantly different from that in the solar neighborhood because of its lower metallicity and lower gas density. We carried out near- and mid…
Simultaneous Photometric and Spectroscopic Analysis of V505 Lacertae, a Photospherically and Chromospherically Active Contact Binary Star
Han, Cheongho; Hong, Kyeongsoo; Kim, Chun-Hwey +4 more
New BVR photometric and high-resolution spectroscopic observations of V505 Lac are presented with Transiting Exoplanet Survey Satellite (TESS) photometric data. The orbital period has experienced a secular decrease during the past 16 yr. A clear anticorrelation in the primary and secondary eclipse timing variation (PSETV) obtained from the TESS da…
Testing Cluster Membership of Planetary Nebulae with High-precision Proper Motions. I. HST Observations of JaFu 1 Near the Globular Cluster Palomar 6
Bond, Howard E.; Sahu, Kailash C.; Bellini, Andrea
If a planetary nebula (PN) is shown to be a member of a star cluster, we obtain important new constraints on the mass and chemical composition of the PN's progenitor star, which cannot be determined for PNe in the field. Cluster membership can be tested by requiring the projected separation between the PN and cluster to be within the tidal radius …
Far-ultraviolet to Far-infrared Spectral Energy Distribution Modeling of the Star Formation History across M31
Hopkins, Andrew M.; Leahy, Denis A.; Hansen, Jakob
Our neighboring galaxy M31 has been recently surveyed at the far- and near-ultraviolet (FUV and NUV) with the UVIT telescope on AstroSat, which provides unprecedented sensitivity to young stellar populations. Here the UVIT data are supplemented with optical data, near-infrared (IR) data (Spitzer), and mid- and far-IR data (Herschel). The observati…
Modeling Circumstellar Gas Emission around a White Dwarf Using CLOUDY
Weinberger, Alycia J.; Steele, Amy; Xu, Siyi +9 more
The chemical composition of an extrasolar planet is fundamental to its formation, evolution, and habitability. In this study, we explore a new way to measure the chemical composition of the building blocks of extrasolar planets by measuring the gas composition of the disrupted planetesimals around white dwarf stars. As a first attempt, we used the…