Search Publications
Evolution of the relation between the mass accretion rate and the stellar and disk mass from brown dwarfs to stars
Bayo, A.; Testi, L.; Alcalá, J. M. +7 more
The time evolution of the dependence of the mass accretion rate with the stellar mass and the disk mass represents a fundamental way to understand the evolution of protoplanetary disks and the formation of planets. In this work, we present observations with X-shooter of 26 Class II very low-mass stars (< 0.2 M⊙) and brown dwarfs in t…
Scylla. II. The Spatially Resolved Star Formation History of the Large Magellanic Cloud Reveals an Inverted Radial Age Gradient
McQuinn, Kristen B. W.; Dolphin, Andrew E.; Murray, Claire E. +11 more
The proximity of the Magellanic Clouds provides the opportunity to study interacting dwarf galaxies near a massive host, and spatial trends in their stellar population properties in particular, with a unique level of detail. The Scylla pure parallel program has obtained deep (80% complete to >1 mag below the ancient main-sequence turnoff), homo…
Fast supermassive black hole growth in the SPT2349–56 protocluster at z = 4.3
Ivison, R. J.; Lehmer, B. D.; Brandt, W. N. +7 more
Context. Large-scale environment is one of the main physical drivers of galaxy evolution. The densest regions at high redshifts (i.e. z > 2 protoclusters) are gas-rich regions characterised by high star formation activity. The same physical properties that enhance star formation in protoclusters are also thought to boost the growth of supermass…
Host Stars and How Their Compositions Influence Exoplanets
Youngblood, Allison; Hinkel, Natalie R.; Soares-Furtado, Melinda
It has become a common practice within the exoplanet field to say that "to know the star is to know the planet." The properties of the host star have a strong, direct influence on the interior and surface conditions of the orbiting planet and oftentimes measurements of planetary properties are made relative to the star's properties. Not only are o…
AT2018fyk: Candidate Tidal Disruption Event by a (Super)Massive Black Hole Binary
Wevers, T.; Li, D.; Kara, E. +8 more
The tidal disruption event (TDE) AT2018fyk has unusual X-ray, UV, and optical light curves that decay over the first ∼600 days, rebrighten, and decay again around 1200 days. We explain this behavior as a one-off TDE associated with a massive black hole (BH) binary. The sharp drop-offs from t ‑5/3 power laws at around 600 days naturally …
Reflection physics in X-ray-emitting symbiotic stars
Toalá, Jesús A.
X-ray-emitting symbiotic stars exhibit a variety of spectral shapes classified as α, β, γ, δ, and β/δ types, which have been attributed to different phenomena such as thermonuclear burning on the surface of the white dwarf component, shocks between winds and jets with the red giant companion's extended atmosphere, the presence of heavily extinguis…
Evidence of apsidal motion and a possible co-moving companion star detected in the WASP-19 system
Rauer, H.; Gandolfi, D.; Csizmadia, Sz. +5 more
Context. Love numbers measure the reaction of a celestial body to perturbing forces, such as the centrifugal force caused by rotation, or tidal forces resulting from the interaction with a companion body. These parameters are related to the interior density profile. The non-point mass nature of the host star and a planet orbiting around each other…
Chemical Diagnostics to Unveil Environments Enriched by First Stars
Cupani, Guido; D'Odorico, Valentina; Becker, George D. +2 more
Unveiling the chemical fingerprints of the first (Population III, hereafter Pop III) stars is crucial for indirectly studying their properties and probing their massive nature. In particular, very massive Pop III stars explode as energetic pair-instability supernovae (PISNe), allowing their chemical products to escape in the diffuse medium around …
Planetary perturbers: flaring star-planet interactions in Kepler and TESS
Ilin, Ekaterina; Alvarado-Gómez, Julián D.; Poppenhäger, Katja +2 more
In many star-planet systems discovered so far, the innermost planet orbits within only a few stellar radii. In these systems, planets could become in situ probes of the extended stellar magnetic field. Because they disturb the field as they move, they are expected to trigger flares in the corona. Potential differences to the energies and morpholog…
Transient fading X-ray emission detected during the optical rise of a tidal disruption event
Liu, Z.; Merloni, A.; Rau, A. +9 more
We report on the SRG/eROSITA detection of ultra-soft ($kT=47^{+5}_{-5}$ eV) X-ray emission (LX =$2.5^{+0.6}_{-0.5} \times 10^{43}$ erg s-1) from the tidal disruption event (TDE) candidate AT 2022dsb ~14 d before peak optical brightness. As the optical luminosity increases after the eROSITA detection, then the 0.2-2 keV observ…