Search Publications
Rieger-type periodicity in the total irradiance of the Sun as a star during solar cycles 23-24
Reiners, A.; Lanza, A. F.; Oliver, R. +4 more
Context. Total solar irradiance allows for the use of the Sun as a star for studying observations of stellar light curves from recent space missions.
Aims: We aim to study how the mid-range periodicity observed in solar activity indices influences the total solar irradiance.
Methods: We studied periodic variations of total solar irradian…
New Positions of Triton Based on Gaia DR2 and New Image-processing Methods
Zhang, H. Y.; Yan, D.; Qiao, R. C. +2 more
The large time span and precise observational data of natural satellites is of great significance for updating their ephemerides and studying their dynamic characteristics. With the help of the new image-processing methods and the Gaia DR2 catalog, all CCD images of Triton taken with the 1.56 m telescope of Shanghai Astronomical Observatory during…
Broadband X-ray spectra and timing of the accreting millisecond pulsar Swift J1756.9-2508 during its 2018 and 2019 outbursts
Huang, Y.; Tsygankov, S. S.; Bozzo, E. +8 more
The accreting millisecond X-ray pulsar Swift J1756.9-2508 launched into an outburst in April 2018 and June 2019 - 8.7 years after the previous period of activity. We investigated the temporal, timing, and spectral properties of these two outbursts using data from NICER, XMM-Newton, NuSTAR, INTEGRAL, Swift, and Insight-HXMT. The two outbursts exhib…
Effect of orbital trapping by bar resonances in the local U-V velocity field
Fernández-Trincado, José G.; Moreno, Edmundo; Chaves-Velasquez, Leonardo +2 more
The effects in the local U-V velocity field due to orbital trapping by bar resonances have been studied computing 15 resonant families in a non-axisymmetric Galactic potential, considering the bar's angular velocity between 35 and 57.5 ${\rm \, km\, s^{-1}{kpc}^{-1}}$. Only cases in the low, 37.5, 40 ${\rm \, km\, s^{-1}{kpc}^{-1}}$, and high, 55,…
A universal relationship between stellar masses and binding energies of galaxies
Chen, Yanmei; Mao, Shude; Shi, Yong +3 more
In this study, we demonstrate that stellar masses of galaxies (Mstar) are universally correlated through a double power-law function with the product of the dynamical velocities (Ve) and sizes to one-fourth power ($R_{\rm e}^{0.25}$) of galaxies, both measured at the effective radii. The product $V_{\rm e}R_{\rm e}^{0.25}$ re…
Miec: A Bayesian hierarchical model for the analysis of nearby young open clusters
Miret-Roig, N.; Bouy, H.; Sarro, L. M. +4 more
Context. The analysis of luminosity and mass distributions of young stellar clusters is essential to understanding the star-formation process. However, the gas and dust left over by this process extinct the light of the newborn stars and can severely bias both the census of cluster members and itsss luminosity distribution.
Aims: We aim to de…
Hot Degenerates in the MCT Survey. III. A Sample of White Dwarf Stars in the Southern Hemisphere
Kepler, S. O.; Fontaine, G.; Bergeron, P. +7 more
We present optical spectra of 144 white dwarfs detected in the Montreal-Cambridge-Tololo colorimetric survey, including 120 DA, 12 DB, 4 DO, 1 DQ, and 7 DC stars. We also perform a model atmosphere analysis of all objects in our sample using the so-called spectroscopic technique, or the photometric technique in the case of DC white dwarfs. The mai…
TESS and HARPS reveal two sub-Neptunes around TOI 1062
Bouchy, F.; Fridlund, M.; Helled, R. +48 more
The Transiting Exoplanet Survey Satellite (TESS) mission was designed to perform an all-sky search of planets around bright and nearby stars. Here we report the discovery of two sub-Neptunes orbiting around TOI 1062 (TIC 299799658), a V = 10.25 G9V star observed in the TESS Sectors 1, 13, 27, and 28. We use precise radial velocity observations fro…
Long-term measurements of the erosion and accretion of dust deposits on comet 67P/Churyumov-Gerasimenko with the OSIRIS instrument
Sierks, H.; Fulle, M.; Güttler, C. +10 more
We monitor the seasonal erosion and accretion of dust deposits in the Imhotep, Hatmehit, and Ma'at regions of comet 67P/Churyumov-Gerasimenko with OSIRIS Narrow Angle Camera images. The vertical accuracy of such measurements is 0.2 m and the spatial scale of the images we used is lower than 0.60 m pixel-1. We calculate the height of 21 …
Precursory Signs of Large Forbush Decreases
Mavromichalaki, H.; Belov, A.; Eroshenko, E. +4 more
The study of space-weather effects and more specifically Forbush decreases of the cosmic-ray intensity depends on space and ground measurements. Very often Forbush decreases and geomagnetic storms are accompanied by pre-increases and/or pre-decreases manifested in cosmic-ray behavior, known as precursory signs. These cosmic-ray intensity variation…