Search Publications
ARCHI: pipeline for light curve extraction of CHEOPS background stars
Guterman, P.; Hoyer, S.; Sousa, Sérgio G. +6 more
High precision time-series photometry from space is being used for a number of scientific cases. In this context, the recently launched CHaracterizing ExOPlanet Satellite (CHEOPS) (ESA) mission promises to bring 20 ppm precision over an exposure time of 6 h, when targeting nearby bright stars, having in mind the detailed characterization of exopla…
Evaluating `twin' parallaxes for binary stars
Jofré, P.; Samadi-Ghadim, A.
Employing Gaia DR2 stellar parallaxes, we tried to first evaluate how `twin parallaxes' are compared with Gaia parallaxes. In the meantime, we checked how different is the performance of twin/Gaia parallaxes for binary stars than for single stars. Our study on a sample of Gaia DR2-RAVE DR5 stars shows that for 70% of them, the twin parallaxes agre…
Results of Astrometric Observations of Distant Satellites of Jupiter with the New Telescope of the Caucasian Mountain Observatory, Sternberg Astronomical Institute, Moscow State University
Emelyanov, N. V.; Safonov, B. S.; Vozyakova, O. V. +1 more
Replenishment of the database of observations of distant satellites of planets is always useful, since the accuracy of the motion models and ephemeris depends not only on the accuracy of observations. Accuracy improves with increasing observation time. Therefore, observations made even with the same accuracy are in demand. Astrometric observations…
Photometry and spectroscopy of massive stars observed during K2 Campaign 8
Eidam, Jéssica M.; Andrade, Laerte; Emilio, Marcelo +4 more
We report in this paper spectroscopic and photometric analysis of eight massive stars observed during Campaign 8 of the Kepler/K2 mission from 2016 January to March. Spectroscopic data were obtained on these stars at OPD/LNA, Brazil, and their stellar parameters determined using SME. Periodic analyses of the light curves were performed through CLE…
Supersolar metallicity in G0-G3 main-sequence stars with V < 15. II. An extension of the sample
Bertone, E.; López-Valdivia, R.; Chávez, M. +1 more
We present the spectroscopic analysis at intermediate resolution of a new sample of 146 Sun-like stars (of spectral types G0-G3 and luminosity class V), which complements the data set of 233 targets previously investigated. Aimed at identifying objects with supersolar metallicity, we conducted observations at the Observatorio Astrofísico Guillermo…
The preliminary orbit of the new massive binary HD 93249
Gamen, R.; Barbá, R.; Morrell, N. I. +1 more
The OWN Survey is a high-resolution spectroscopic monitoring of Southern O and WN-type stars, whose multiplicity status is unknown. This project started more than ten years ago and it has discovered an important number of new binaries and other multiple systems. In this context, we present the first spectroscopic orbit of HD~93249, the brightest m…
Embedded clusters: upgrading visual and infrared photometric analysis with Gaia DR2 and ASteCA
Perren, G. I.; Vázquez, R. A.; Giorgi, E. E. +3 more
Embedded clusters are groups of stars which have not dispersed yet the residual of the parental cloud where they were born, thus getting precise distances and properties ofthese groups is an essential task. We present results for five embedded clusters: [DBS2003]5, [DBS2003]60, [DBS2003]98, [DBS2003]116 and [DBS2003]117, obtained from a combinatio…
V725 Sagittarii: Unique, Important, Neglected
Percy, J. R.
During the last century, V725 Sgr gradually changed from a 12-day Cepheid to an 85-day yellow semiregular giant. This paper presents wavelet analysis of AAVSO visual observations from 1982 to 2020, and Fourier analysis of ASAS-SN observations from 2016 to 2018. The results confirm that the previously-identified pulsation period has increased from …
Two close binaries across the hydrogen-burning limit in the Praesepe open cluster
Rebolo, R.; del Burgo, C.; Alvarez, C. +7 more
We present Keck I/OSIRIS and Keck II/NIRC2 adaptive optics imaging of two member candidates of the Praesepe stellar cluster (d = 186.18 ± 0.11 pc; 590-790 Myr), UGCS J08451066+2148171 (L1.5 ± 0.5) and UGCS J08301935+2003293 (no spectroscopic classification). We resolved UGCS J08451066+2148171 into a binary system in the near-infrared, with a K-ban…
The Reclassification of NSV 1586 from a Suspected Cepheid Star to a UG Class System
Hills, K.; Brincat, S. M.; Galdies, C. +1 more
On 2018 August 9, a contribution to the VSNET mailing list suggested that due to certain photometric attributes, NSV 1586 could possibly belong to the Dwarf Nova (DN) class. Hence, the initial classification of this star as a Cepheid variable star was put into question. This prompted the authors to investigate NSV 1586 in detail. The data obtained…