Search Publications
Ephemerides of the Irregular Saturnian Satellites from Earth-based Astrometry and Cassini Imaging
Jacobson, Robert A.; Sheppard, Scott S.; Brozović, Marina +2 more
We report a new determination of the orbits of the irregular Saturnian satellites. We fit their numerically integrated orbits to a data set containing Earth-based observations and imaging data from the Cassini spacecraft. We include the statistics of the observation residuals, the satellites' orbital elements, and projected accuracies of the satel…
The η Aquilae System: Radial Velocities and Astrometry in Search of η Aql B
Cochran, William D.; Harrison, Thomas E.; Anderson, Richard I. +4 more
The classical Cepheid η Aql was not included in past Leavitt Law work because of a presumed complicating orbit due to a known B9.8V companion. To determine the orbit of η Aql B, we analyze a significant number of radial velocity (RV) measurements from eight sources. With these we establish the RV variation due to Cepheid pulsation, using a model w…
USNO Bright Star Catalog, Version 1
Harris, Hugh C.; Munn, Jeffrey A.; Subasavage, John P. +3 more
The USNO Bright Star Catalog (UBSC) is a new astrometric catalog of the 1423 brightest stars covering the entire sky, which is published online. It is nearly complete to V = 3 mag except for three stellar systems. A combined astrometric solution of the Hipparcos Intermediate Astrometry Data and two dedicated ground-based campaigns in 2013-2020 is …
Revisit of Open Clusters UPK 39, UPK 41, and PHOC 39: A New Binary Open Cluster Found
Zhao, Gang; Yang, Yong; Zhao, Jingkun +2 more
We investigate the three open clusters near the Aquila Rift cloud, named UPK 39 (c1 hereafter), UPK 41 (c2 hereafter) in Sim et al. (2019), and PHOC 39 (c3 hereafter) in Hunt & Reffert (2021). Using photometric passpands, reddening, and extinction from Gaia DR3, we construct the color-absolute-magnitude diagram. Using isochrone fits, their age…
OGLE-2016-BLG-1093Lb: A Sub-Jupiter-mass Spitzer Planet Located in the Galactic Bulge
Han, Cheongho; Udalski, Andrzej; Lee, Chung-Uk +62 more
OGLE-2016-BLG-1093 is a planetary microlensing event that is part of the statistical Spitzer microlens parallax sample. The precise measurement of the microlens parallax effect for this event, combined with the measurement of finite-source effects, leads to a direct measurement of the lens masses and system distance, M host =0.38-0.57 M…
Catalog of Wide Binary, Trinary and Quaternary Candidates from the Gaia Data Release 2 (Region ∣b∣ > 25°)
Zavada, Petr; Píška, Karel
The occurrence of multiple stars, dominantly binaries, is studied using the Gaia-ESA DR2 catalog. We apply the optimized statistical method that we previously developed for the analysis of 2D patterns. The field of stars is divided into a mosaic of small pieces that represent a statistical set for analysis. Specifically, data input is represented …
Multiwavelength Mitigation of Stellar Activity in Astrometric Planet Detection
Solanki, Sami K.; Macintosh, Bruce; Krivova, Natalie +4 more
Astrometry has long been a promising technique for exoplanet detection. At the theoretical limits, astrometry would allow for the detection of smaller planets than previously seen by current exoplanet search methods, but stellar activity may make these theoretical limits unreachable. Astrometric jitter of a Sun-like star due to magnetic activity i…
KK 242, A Faint Companion to the Isolated Scd Galaxy NGC 6503
Cannon, John M.; Anand, Gagandeep S.; Tully, R. Brent +4 more
Using Hubble Space Telescope imaging of the resolved stellar population of KK 242 = NGC 6503-d1 =PGC 4689184, we measure the distance to the galaxy to be 6.46 ± 0.32 Mpc and find that KK 242 is a satellite of the low-mass spiral galaxy NGC 6503 located on the edge of the Local Void. Observations with the Karl G. Jansky Very Large Array show signs …
Visual Orbits of Spectroscopic Binaries with the CHARA Array. IV. HD 61859, HD 89822, HD 109510, and HD 191692
Gies, Douglas R.; Lester, Kathryn V.; Monnier, John D. +18 more
We present the visual orbits of four spectroscopic binary stars, HD 61859, HD 89822, HD 109510, and HD 191692, using long baseline interferometry with the CHARA Array. We also obtained new radial velocities from echelle spectra using the APO 3.5 m, CTIO 1.5 m, and Fairborn Observatory 2.0 m telescopes. By combining the astrometric and spectroscopi…
Accurate Ground-based Astrometry of Naked-eye Stars: The United States Naval Observatory Bright-star Astrometric Database
Harris, Hugh C.; Munn, Jeffrey A.; Subasavage, John P. +1 more
We present the United States Naval Observatory (USNO) Bright-star Astrometric Database (UBAD), a current-epoch high-accuracy astrometric catalog. The catalog consists of 364 bright northern hemisphere stars, including all but five such stars with either V < 3.5 or with I < 3.2 and V < 6, as well as a large fraction of slightly fainter sta…