Search Publications
Jeans modelling of the Milky Way's nuclear stellar disc
Mastrobuono-Battisti, Alessandra; Neumayer, Nadine; Klessen, Ralf S. +4 more
The nuclear stellar disc (NSD) is a flattened stellar structure that dominates the gravitational potential of the Milky Way at Galactocentric radii $30 \lesssim R \lesssim 300\, {\rm pc}$ . In this paper, we construct axisymmetric Jeans dynamical models of the NSD based on previous photometric studies and we fit them to line-of-sight kinematic dat…
Properties of flares and CMEs on EV Lac: possible erupting filament
Guenther, E. W.; Muheki, Priscilla; Mutabazi, T. +1 more
Flares and coronal mass ejections (CMEs) are very powerful events in which energetic radiation and particles are ejected within a short time. These events thus can strongly affect planets that orbit these stars. This is particularly relevant for planets of M-stars, because these stars stay active for a long time during their evolution and yet pote…
The compact triply eclipsing triple star TIC 209409435 discovered with TESS
Huang, X.; Mitnyan, T.; Pál, A. +9 more
We report the discovery in TESS Sectors 3 and 4 of a compact triply eclipsing triple star system. TIC 209409435 is a previously unknown eclipsing binary with a period of 5.717 d, and the presence of a third star in an outer eccentric orbit of 121.872-d period was found from two sets of third-body eclipses and from eclipse timing variations. The la…
Discovery of a hot ultramassive rapidly rotating DBA white dwarf
Postnov, K. A.; Blinnikov, S. I.; Dodin, A. V. +6 more
We report the discovery of a nearby massive white dwarf with He-H atmosphere. The white dwarf is located at a distance of 74.5 ± 0.9-=pc. Its radius, mass, effective temperature, H/He ratio, and age are R = 2500 ± 100-=km, M = 1.33 ± 0.01-= $\rm M_{\odot }$ , Teff = 31-=200 ± 1200-=K, H/He ∼ 0.1, and 330 ± 40-=Myr, respectively. The obs…
Detailed chemical compositions of planet-hosting stars - I. Exploration of possible planet signatures
Spina, L.; Yong, D.; Asplund, M. +5 more
We present a line-by-line differential analysis of a sample of 16 planet-hosting stars and 68 comparison stars using high-resolution, high signal-to-noise ratio spectra gathered using Keck. We obtained accurate stellar parameters and high-precision relative chemical abundances with average uncertainties in Teff, log g, [Fe/H], and [X/H]…
A census of coronal mass ejections on solar-like stars
Lammer, H.; Guenther, E. W.; Kriskovics, L. +8 more
Coronal mass ejections (CMEs) may have major importance for planetary and stellar evolution. Stellar CME parameters, such as mass and velocity, have yet not been determined statistically. So far only a handful of stellar CMEs has been detected mainly on dMe stars using spectroscopic observations. We therefore aim for a statistical determination of…
On the black hole content and initial mass function of 47 Tuc
Balbinot, E.; Hénault-Brunet, V.; Gieles, M. +3 more
The globular cluster (GC) 47 Tuc has recently been proposed to host an intermediate-mass black hole (IMBH) or a population of stellar mass black holes (BHs). To shed light on its dark content, we present an application of self-consistent multimass models with a varying mass function and content of stellar remnants, which we fit to various observat…
Strong chemical tagging with APOGEE: 21 candidate star clusters that have dissolved across the Milky Way disc
Cohen, Roger E.; Bovy, Jo; Brownstein, Joel R. +12 more
Chemically tagging groups of stars born in the same birth cluster is a major goal of spectroscopic surveys. To investigate the feasibility of such strong chemical tagging, we perform a blind chemical tagging experiment on abundances measured from APOGEE survey spectra. We apply a density-based clustering algorithm to the 8D chemical space defined …
Thermal stability of winds driven by radiation pressure in super-Eddington accretion discs
Mehdipour, M.; Ness, J. -U.; Guainazzi, M. +7 more
Ultraluminous X-ray sources (ULXs) are mainly powered by accretion in neutron stars or stellar-mass black holes. Accreting at rates exceeding the Eddington limit by factors of a few up to hundreds, radiation pressure is expected to inflate the accretion disc, and drive fast winds that have in fact been observed at significant fractions of the spee…
Asymmetric surface brightness structure of caustic crossing arc in SDSS J1226+2152: a case for dark matter substructure
Miralda-Escudé, Jordi; Rigby, Jane R.; Bayliss, Matthew +6 more
We study the highly magnified arc SGAS J122651.3+215220 caused by a star-forming galaxy at zs = 2.93 crossing the lensing caustic cast by the galaxy cluster SDSS J1226+2152 (zl = 0.43), using Hubble Space Telescope observations. We report in the arc several asymmetric surface brightness features whose angular separations are …