Search Publications
Evolution of brightness and magnetic features of young solar-type stars - II. The young F8 star HIP 71933
Hébrard, E. M.; Hughes, J. E.; Marsden, S. C. +4 more
The early, active history of our Sun is still not fully understood. Observations of the magnetic fields on active young solar-type stars allow us an insight into the early evolution of our Sun. Here we present Doppler and Zeeman-Doppler images of the young late-F star HIP 71933 (HD 129181) at multiple epochs to add to the growing data about the ev…
A multiwavelength study of the IRAS 23139+5939 (G111.256-0.770) star-forming site and its relation to Sh2-157
Tapia, Mauricio; Persi, Paolo
The far-infrared source IRAS 23139+5939 (G111.25-0.77) is a well-studied massive star-forming region at the centre of a dense molecular clump. It is associated with a low-luminosity and variable methanol maser, a number of water maser clusters, and several compact H II regions. We present new sub-arcsec-resolution broad- and narrow-band near- and …
Search of nearby resolved neutron stars among optical sources
Bihain, Gabriel
Neutron stars are identified as pulsars, X-ray binary components, central objects of supernovae remnants, or isolated thermally emitting sources and at distances beyond 120 pc. A population extrapolation suggests 103 objects within that boundary. Potentially, neutron stars could continuously emit gravitational waves at sensitivity reach…
TFAW survey II: six newly validated planets and 13 planet candidates from K2
Tokovinin, A.; Dyachenko, V.; del Ser, D. +7 more
Searching for Earth-sized planets in data from Kepler's extended mission (K2) is a niche that still remains to be fully exploited. The TFAW survey is an ongoing project that aims to re-analyse all light curves in K2 C1-C8 and C12-C18 campaigns with a wavelet-based detrending and denoising method, and the period search algorithm TLS to search for n…
Probing the nature of the X-ray source IGR J16327-4940 with Chandra
Sidoli, L.; Esposito, P.; Postnov, K. +3 more
We report on the results of a Chandra observation of the source IGR J16327-4940, suggested to be a high-mass X-ray binary hosting a luminous blue variable star (LBV). The source field was imaged by ACIS-I in 2023 to search for X-ray emission from the LBV star and eventually confirm this association. No X-ray emission is detected from the LBV star,…
Probing quasar viewing angle with the variability structure function
Tang, Ji-Jia; Wolf, Christian; Tonry, John +3 more
Given the anisotropic emission from quasar accretion discs, their viewing angle affects estimates of the quasar luminosity, black hole mass, and Eddington ratio. Discs appear overluminous when viewed pole-on and underluminous when viewed at high inclination. In radio-quiet quasars, the viewing angle is usually unknown, although spectroscopic indic…
A CCD search for variable stars in the open cluster NGC 6611
Leiton, R.; Kołaczkowski, Z.; Kalari, V. M. +3 more
We present the results of the UBVIC variability survey in the young open cluster NGC 6611 based on observations obtained during 34 nights spanning one year. In total, we found 95 variable stars. Most of these stars are classified as periodic and irregular pre-main sequence (PMS) stars. The analysis of the JHKS 2MASS photometr…
A photoelectric study of the eclipsing binary EG Serpentis
Thurman, Glenn M.
A ubvy photoelectric study of the early A-type, detached eclipsing binary EG Serpentis (EG Ser) has been undertaken at Mount Laguna Observatory. Simultaneous observation on two telescopes has been employed for the first time at the observatory. Approximately 2000 standardized differential magnitudes are presented along with standardized colours an…
The odd bunch: chrono-chemo-dynamics of sixteen unusual stars from Kepler
Monty, Stephanie; Stello, Dennis; Casagrande, Luca +4 more
In this study we combine asteroseismic, spectroscopic, and kinematic information to perform a detailed analysis of a sample of 16 stars from the Kepler field. Our selection focuses on stars that appear to contradict Galactic chemical evolution models: young and α-rich, old and metal-rich, as well as other targets with unclear classification in pas…
T Tauri stars in the SuperWASP and NSVS surveys II. Spectral modelling
Munari, U.; Smalley, B.; Kundra, E. +9 more
We present results from long-term spectroscopic monitoring of 21 T-Tauri stars located in the Taurus-Auriga star-forming region (SFR). We combine medium and high-dispersion Echelle spectroscopy obtained at the Stará Lesná, Skalnaté Pleso (both in Slovakia), and Tautenburg (Germany) observatories with low-resolution flux-calibrated spectra from Asi…