Search Publications
Searching for Active Low-mass Stars in the CMa Star-forming Region: Multi-band Photometry with T80S
Montmerle, T.; Galli, P. A. B.; Perottoni, H. D. +10 more
An exotic environment surrounds the young stellar groups associated with the Canis Major (CMa) OB1/R1 region, which probably was formed under feedback from at least three supernova events having occurred a few million years ago. We use astrometric data from the Gaia-DR2 to confirm the membership of the stars in CMa R1, based on proper motion and p…
Improvements to Pan-STARRS1 Astrometry Using Gaia
White, Richard L.; Shiao, Bernie; Lubow, Stephen H.
We use the Gaia DR2 catalog to improve the astrometric accuracy of about 1.7 billion objects in Pan-STARRS1 Data Release 2 (PS1 DR2). We also obtain proper motions for these PS1 objects. The cross-match between Gaia and PS1 reveals residuals that are correlated on a scale of about 1'. We apply a spatially adaptive correction algorithm for all PS1 …
Discovery of 22 GHz Water Masers in the Serpens South Region
Gong, Yan; Pillai, Thushara; Loinard, Laurent +5 more
Using the Karl G. Jansky Very Large Array (VLA), we have conducted a survey for 22 GHz, 61,6-52,3 H2O masers toward the Serpens South region. The masers were also observed with the Very Long Baseline Array following the VLA detections. We detect for the first time H2O masers in the Serpens South region t…
A CO-to-H2 Ratio of ≈10-5 toward the Herbig Ae Star HK Ori
France, Kevin; Johns-Krull, Christopher M.; Cauley, P. Wilson +1 more
Measurements of gas mass in protoplanetary gas disks form the basis for estimating the conditions of planet formation. Among the most important constraints derived from disk diagnostics are the abundances of gas-phase species critical for understanding disk chemistry. Toward this end, we present direct line-of-sight measurements of H2 a…
Variability in Protoplanetary Nebulae. VIII. A New Sample of Southern Hemisphere Objects
Lu, Wenxian; Hrivnak, Bruce J.; Henson, Gary +5 more
As part of our continuing study of light variability in protoplanetary nebulae (PPNe), we present the results from a long-term study of nine southern hemisphere objects. We have monitored their light variations over a nine-year interval from 2010 to 2018. These were supplemented by data from the ASAS-SN and ASAS-3 surveys, leading to combined ligh…
Joint Analysis of Multicolor Photometry: A New Approach to Constrain the Nature of Multiple-star Systems Hosting Exoplanet Candidates
Miyakawa, Kohei; Hirano, Teruyuki; Sato, Bun'ei +2 more
We present a new method to assess the properties of transiting planet candidates by multicolor photometry. By analyzing multicolor transit/eclipse light curves and apparent magnitudes of the target in parallel, this method attempts to identify the nature of the system and provide a quantitative constraint on the properties of unresolved companion(…
Globular Cluster Candidates in the Sagittarius Dwarf Galaxy
Piatti, Andrés E.
Recently, new Sagittarius (Sgr) dwarf-galaxy globular clusters were discovered, which opens the question of the actual size of the Sgr globular cluster population, and therefore on our understanding of the Sgr galaxy formation and accretion history of the Milky Way. Based on Gaia EDR3 and SDSS IV DR16 (APOGEE-2) data sets, we performed an analysis…
Multifilter Observations of the Complex Periodic Variations in the M-dwarf Star RIK 90
Koen, Chris
The star RIK 90 is a member of a group of recently discovered young T Tauri stars showing complex periodic modulations of their light output, which have been difficult to explain. As one of the brightest, and having a relatively short period, RIK 90 is of particular interest. Thirty-three hours of contemporaneous BVRCIC photo…
X-Rays in Cepheids: XMM-Newton Observations of η Aql
Mérand, Antoine; Drake, Jeremy J.; Guzik, Joyce A. +13 more
X-ray bursts have recently been discovered in the Cepheids δ Cep and β Dor modulated by the pulsation cycle. We have obtained an observation of the Cepheid η Aql with the XMM-Newton satellite at the phase of maximum radius; the phase at which there is a burst of X-rays in δ Cep. No X-rays were seen from the Cepheid η Aql at this phase, and the imp…
Functional Principal Component Analysis of Radio-Optical Reference Frame Tie
Makarov, Valeri V.
The Gaia optical reference frame is intrinsically undefined with respect to global orientation and spin, so it needs to be anchored in the radio-based International Celestial Reference Frame (ICRF) to provide a referenced and quasi-inertial celestial coordinate system. The link between the two fundamental frames is realized through two samples of …