Search Publications
Detection and characterization of stellar magnetic activity with Gaia
Lanzafame, Alessandro; Distefano, Elisa
The Gaia Data Release 2 (DR2) supplied a catalog of 147,644 late-type stars for which the analysis of the G-band photometric time series allowed the detection of the rotation period and an estimate of the magnetic activity level. The Gaia DR3 will be based on photometric time series spanning a longer time interval and will allow the detection and …
Global parameters of the W UMa stars FI Lyn, UV Lyn, and NSVS 781878
Popov, Velimir A.; Kjurkchieva, Diana P.; Marchev, Dragomir V. +1 more
Photometric and spectral observations of the W UMa binaries FI Lyn, UV Lyn, and NSVS 781878 with periods of around 9.5–10 hr were carried out in order to determine their global parameters by simultaneous light curve and radial velocity curve solutions. We found that the three targets have shallow‑contact configurations with close in mass and radiu…
Composite Spectra, Paper XXIII: HD 69479/80, a 90‑day binary with a cool‑giant primary
Griffin, R. Elizabeth; Griffin, Roger F.
HD 69479/80 is a composite‑spectrum binary whose components are a late‑G giant and an early‑A dwarf. The orbit has a period of only 91 days (which seems short for a system containing a cool giant with a radius of ∼13 solar radii), and a very small, but probably significantly non‑zero, eccentricity. We separated the component spectra by a procedure…
The HD 217107 planetary system: Twenty years of radial velocity measurements
Kane, Stephen R.; Horner, Jonathan; Eastman, Jason D. +13 more
The hot Jupiter HD 217107 b was one of the first exoplanets detected using the radial velocity (RV) method, originally reported in the literature in 1999. Today, precise RV measurements of this system span more than 20 years, and there is clear evidence of a longer-period companion, HD 217107 c. Interestingly, both the short-period planet (Pb…
Latitude observations of the last century to obtain accurate independent latitude stations (INDLS) catalog of µδ for 682 Hipparcos stars and comparison with Gaia DR2
Damljanović, Goran
The independent latitude stations (INDLS) catalog of proper motion in declination µδ for 682 bright Hipparcos (HIP) stars is presented. It is obtained in the Hipparcos reference frame, and only the Hipparcos mean position at epoch 1991.25 is used for INDLS data to calculate independent µδ (the HIP µδ values are not included in th…
On the binary orbit of Henry Draper one ( HD 1)
Strassmeier, Klaus G.; Weber, Michael
We present our final orbit for the late type spectroscopic binary Henry Draper one (HD 1). area total of 553 spectra from 13 years of observations are used with our robotic STELLA facility and its high resolution echelle spectrograph SES. Its long term radial velocity stability is ≈50 m s-1. A single radial velocity of HD 1 reached an r…
MACHO 311.37557.169: A VY Scl star
Brown, Michael J. I.; Schwope, Axel D.; Traulsen, Iris +1 more
Optical surveys, such as the MACHO project, often uncover variable stars whose classification requires follow‑up observations by other instruments. We performed X‑ray spectroscopy and photometry of the unusual variable star MACHO 311.37557.169 with XMM‑Newton in April 2018, supplemented by archival X‑ray and optical spectrographic data. The star h…
Some notes concerning open clusters and GAIA DR2 data
Loktin, Alexander Vasilievich; Popova, Maria Erikovna
Issues in applying the Gaia DR2 data to determine the main parameters of open star clusters and the use of a formal, two color diagram for the initial selection of cluster members are discussed. The possibility of using the catalog estimates of interstellar absorption is considered. It has been shown that these estimates correlate with the E(B - V…
Follow‑up imaging observations of comet 2I/Borisov
Mugrauer, Markus; Schlagenhauf, Saskia; Bischoff, Richard +3 more
Follow‑up imaging observations of the first detected interstellar comet 2I/Borisov are presented, which were carried out with the Schmidt‑Teleskop‑Kamera at the University Observatory Jena in 11 observing epochs in October and November 2019. The orbital solution of the comet, derived from the obtained astrometric measurements, confirms its highly …
Editor's note
Schartel, Norbert