Search Publications
The Family of V1311 Ori: a Young Sextuple System or a Minicluster?
Tokovinin, Andrei
A compact bound group of four active M-type dwarfs containing V1311 Ori is identified in the Gaia catalog of nearby stars. Located at a distance of 39 pc, it is likely related to the β Pictoris and 32 Ori moving groups by kinematics, isochronal age, and other indicators of youth (Hα emission, presence of lithium, and fast rotation). The brightest …
Around the Spindle Galaxy: The Dark Halo Mass of NGC 3115
Karachentsev, I. D.; Anand, G. S.; Makarova, L. N. +1 more
We report observations of five dwarf galaxies in the vicinity of the luminous S0 galaxy NGC 3115 performed with the Advanced Camera for Surveys on the Hubble Space Telescope. Their distances determined via the Tip of the Red Giant Branch are: 10.05 Mpc (UGCA 193), 9.95 Mpc (KKSG 17), 10.13 Mpc (2MASX-J0957-0915), 10.42 Mpc (2dFGRS-TGN218Z179), and…
Detection of Na and K in the Atmosphere of the Hot Jupiter HAT-P-1b with P200/DBSP
Wang, Hongchi; van Boekel, Roy; Chen, Guo +1 more
We present a new optical transmission spectrum of the hot Jupiter HAT-P-1b based on two transits observed with the Double Spectrograph (DBSP) on the Palomar 200-inch (P200) telescope. The DBSP transmission spectrum, covering a wavelength range from 3250 to 10007 Å, is consistent with that observed with the Hubble Space Telescope (HST), but the for…
A Comprehensive Study of Five Intermediate-age Pismis (2, 3, 7, 12, 15) Clusters Using Photometric and Astrometric Data from Gaia EDR3
Bisht, D.; Rangwal, Geeta; Yadav, R. K. S. +5 more
Open clusters are groups of stars that form simultaneously; hence, these are excellent probes to test theories of star formation, stellar evolution, and dynamics in the Milky Way disk. We carry out a detailed photometric and kinematic study of five poorly studied intermediate-age open clusters, Pismis 2 (Pi 2), Pismis 3 (Pi 3), Pismis 7 (Pi 7), Pi…
K2-79b and K2-222b: Mass Measurements of Two Small Exoplanets with Periods beyond 10 days that Overlap with Periodic Magnetic Activity Signals
Vanderburg, Andrew; López-Morales, Mercedes; Bieryla, Allyson +28 more
We present mass and radius measurements of K2-79b and K2-222b, two transiting exoplanets orbiting active G-type stars observed with HARPS-N and K2. Their respective 10.99 day and 15.39 day orbital periods fall near periods of signals induced by stellar magnetic activity. The two signals might therefore interfere and lead to an inaccurate estimate …
Confirmation of the Long-period Planet Orbiting Gliese 411 and the Detection of a New Planet Candidate
Rosenthal, Lee J.; Howard, Andrew W.; Petigura, Erik A. +4 more
We perform a detailed characterization of the planetary system orbiting the bright, nearby M dwarf Gliese 411 using radial velocities gathered by APF, HIRES, SOPHIE, and CARMENES. We confirm the presence of a signal with a period near 2900 days that has been disputed as either a planet or a long-period stellar magnetic cycle. An analysis of activi…
The µ Arae Planetary System: Radial Velocities and Astrometry
McArthur, B. E.; Benedict, G. F.; Nelan, E. P. +4 more
With Hubble Space Telescope Fine Guidance Sensor astrometry and published and previously unpublished radial velocity measures, we explore the exoplanetary system µ Arae. Our modeling of the radial velocities results in improved orbital elements for the four previously known components. Our astrometry contains no evidence for any known compan…
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…