Search Publications
KKH 22, the first dwarf spheroidal satellite of IC 342
Anand, Gagandeep S.; Shaya, Edward J.; Karachentsev, Igor D. +4 more
Aims: We present observations with the Advanced Camera for Surveys on the Hubble Space Telescope of the nearby dwarf spheroidal galaxy KKH 22 = LEDA 2807114 in the vicinity of the massive spiral galaxy IC 342.
Methods: We derived its distance of 3.12 ± 0.19 Mpc using the tip of red giant branch (TRGB) method. We also used the 6 m BTA spe…
Migration jumps of planets in transition discs
Rometsch, Thomas; Rodenkirch, Peter J.; Kley, Wilhelm +1 more
Context. Transition discs form a special class of protoplanetary discs that are characterised by a deficiency of disc material close to the star. In a subgroup, inner holes in these discs can stretch out to a few tens of au while there is still mass accretion onto the central star observed at the same time.
Aims: We analyse the proposition th…
Predicting frequency changes of global-scale solar Rossby modes due to solar cycle changes in internal rotation
Birch, A. C.; Gizon, L.; Fournier, D. +1 more
Context. Large-scale equatorial Rossby modes have been observed on the Sun over the last two solar cycles.
Aims: We investigate the impact of the time-varying zonal flows on the frequencies of Rossby modes.
Methods: A first-order perturbation theory approach is used to obtain an expression for the expected shift in the mode frequencies d…
Unexpected late-time temperature increase observed in the two neutron star crust-cooling sources XTE J1701-462 and EXO 0748-676
Degenaar, N.; Wijnands, R.; Homan, J. +4 more
Transient low-mass X-ray binaries (LMXBs) that host neutron stars (NSs) provide excellent laboratories for probing the dense matter physics present in NS crusts. During accretion outbursts in LMXBs, exothermic reactions may heat the NS crust, disrupting the crust-core equilibrium. When the outburst ceases, the crust cools to restore thermal equili…
Binary star sequence in the outskirts of the disrupting Galactic open cluster UBC 274
Piatti, Andrés E.
We report the identification of a numerous binary star population in the recently discovered ∼3 Gyr old open cluster UBC 274. It becomes visible when the cluster color-magnitude diagram is corrected by differential reddening and spans mass ratio (q) values from 0.5 up to 1.0. Its stellar density radial profile and cumulative distribution as a func…
The highly inflated giant planet WASP-174b
Henning, Th.; Southworth, J.; Chen, G. +18 more
Context. The transiting exoplanetary system WASP-174 was reported to be composed by a main-sequence F star (V = 11.8 mag) and a giant planet, WASP-174b (orbital period Porb = 4.23 days). However only an upper limit was placed on the planet mass (<1.3 MJup), and a highly uncertain planetary radius (0.7-1.7 RJup) …
Understanding the rotational variability of K2 targets. HgMn star KIC 250152017 and blue horizontal branch star KIC 249660366
Fossati, L.; Skarka, M.; Krtička, J. +6 more
Context. Ultraprecise space photometry enables us to reveal light variability even in stars that were previously deemed constant. A large group of such stars show variations that may be rotationally modulated. This type of light variability is of special interest because it provides precise estimates of rotational rates.
Aims: We aim to under…
A new multiwavelength census of blazars
Villata, M.; De Zotti, G.; Carnerero, M. I. +3 more
Context. Blazars are the rarest and most powerful active galactic nuclei. They play a crucial and expanding role in the multifrequency and multimessenger astrophysics of today. Dominating the high-energy extragalactic sky, they have been recently associated with high-energy astrophysical neutrinos and they may be among the accelerators of the ultr…
Mapping the working of environmental effects in A963
Hwang, Ho Seong; Finoguenov, Alexis; Ziegler, Bodo +5 more
Aims: We qualitatively assess and map the relative contribution of pre-processing and cluster related processes to the build-up of
Methods: We use Voronoi binning of positions of cluster members on the plane …
Very fast variations of SiO maser emission in evolved stars
Alcolea, J.; Bujarrabal, V.; de Vicente, P. +3 more
Context. Stars on the asymptotic giant branch (AGB) are long-period variables that present strong flux variations at almost all wavelengths, including the SiO maser lines. The periods of these variations are of 300-500 days in Mira-type stars and somewhat shorter in semi-regular variables. The variability of the SiO lines on short timescales has b…