Search Publications
Chemical diversity among A-B stars with low rotational velocities: non-LTE abundance analysis
Ryabchikova, T.; Sitnova, T.; Mashonkina, L. +2 more
We present accurate element abundance patterns based on the non-local thermodynamic equilibrium (non-LTE, NLTE) line formation for 14 chemical elements from He to Nd for a sample of nine A9 to B3-type stars with well-determined atmospheric parameters and low rotational velocities. We constructed new model atom of Zr II-III and updated model atoms …
Characterizing low-contrast Galactic open clusters with Gaia Data Release 2
Corradi, W. J. B.; Santos, J. F. C.; Angelo, M. S.
In this study, we characterized 16 objects previously classified as faint or low-contrast Galactic open clusters (OCs). We employed parameters associated with the dynamical evolution of the OCs: the core (rc), tidal (rt) and half-mass (rhm) radii, age and crossing time (tcr). Relations among these parame…
A full characterization of the supermassive black hole in IRAS-=09149-6206
Harrison, F. A.; Stern, D.; Fabian, A. C. +11 more
We present new broad-band X-ray observations of the type-I Seyfert galaxy IRAS 09149-6206, taken in 2018 with XMM-Newton, NuSTAR, and Swift. The source is highly complex, showing a classic 'warm' X-ray absorber, additional absorption from highly ionized iron, strong relativistic reflection from the innermost accretion disc and further reprocessing…
The effects of dwarf galaxies on the orbital evolution of galactic globular clusters
Bovy, Jo; Webb, Jeremy J.; Garrow, Turner
We investigate the effect that dwarf galaxies have on the orbits, tidal histories, and assumed formation environment of Milky Way globular clusters. We determine the orbits of the Milky Way's 150 globular clusters in a gravitational potential both with and without dwarf galaxies. We find that the presence of a small number of satellite galaxies ca…
The stellar variability noise floor for transiting exoplanet photometry with PLATO
Hawley, Suzanne L.; Agol, Eric; Morris, Brett M. +2 more
One of the main science motivations for the ESA PLAnetary Transit and Oscillations (PLATO) mission is to measure exoplanet transit radii with 3 per cent precision. In addition to flares and starspots, stellar oscillations and granulation will enforce fundamental noise floors for transiting exoplanet radius measurements. We simulate light curves of…
Mode identification in three pulsating hot subdwarfs observed with TESS satellite
Heber, U.; Irrgang, A.; Raddi, R. +12 more
We report on the detection of pulsations of three pulsating subdwarf B stars observed by the Transiting Exoplanet Survey Satellite (TESS) satellite and our results of mode identification in these stars based on an asymptotic period relation. SB 459 (TIC 067584818), SB 815 (TIC 169285097), and PG 0342 + 026 (TIC 457168745) have been monitored durin…
Physical conditions in the diffuse interstellar medium of local and high-redshift galaxies: measurements based on the excitation of H2 rotational and C I fine-structure levels
Balashev, S. A.; Klimenko, V. V.
We present the results of an analysis of the physical conditions (number density, intensity of UV field, kinetic temperature) in the cold H2-bearing interstellar medium of local and high-redshift galaxies. Our measurements are based on the fit to the observed population of H2 rotational levels and C I fine-structure levels wi…
Constraining the depth of the winds on Uranus and Neptune via Ohmic dissipation
Helled, Ravit; Soyuer, Deniz; Soubiran, François
Determining the depth of atmospheric winds in the outer planets of the Solar system is a key topic in planetary science. We provide constraints on these depths in Uranus and Neptune via the total induced Ohmic dissipation, due to the interaction of the zonal flows and the planetary magnetic fields. An upper bound can be placed on the induced dissi…
A period-dependent spatial scatter of Galactic black hole transients
Maccarone, T. J.; Charles, P. A.; Gandhi, P. +4 more
There remain significant uncertainties in the origin and evolution of black holes in binary systems, in particular regarding their birth sites and the influence of natal kicks. These are long-standing issues, but their debate has been reinvigorated in the era of gravitational wave detections and the improving precision of astrometric measurements.…
The Magellan/PFS Exoplanet Search: a 55-d period dense Neptune transiting the bright (V = 8.6) star HD 95338
Butler, R. Paul; Kane, Stephen R.; Crane, Jeffrey D. +14 more
We report the detection of a transiting, dense Neptune planet candidate orbiting the bright (V = 8.6) K0.5V star HD 95338. Detection of the 55-d periodic signal comes from the analysis of precision radial velocities from the Planet Finder Spectrograph on the Magellan II Telescope. Follow-up observations with HARPS also confirm the presence of the …