Search Publications
Tidally perturbed oblique pulsations in the hierarchical triple system V1031 Orionis
Lee, Jae Woo
We present Transiting Exoplanet Survey Satellite (TESS) photometry of the triple star system V1031 Ori (AB)C, which exhibits short-period oscillations superimposed on an eclipsing light curve.The high-quality data were analyzed in detail and combined with the published spectroscopic measurements to obtain the fundamental stellar parameters of the …
Constraining stellar rotation and planetary atmospheric evolution of a dozen systems hosting sub-Neptunes and super-Earths
Fossati, L.; Kubyshkina, D.; Bonfanti, A. +1 more
Context. Planetary atmospheric evolution modelling is a prime tool for understanding the observed exoplanet population and constraining formation and migration mechanisms, but it can also be used to study the evolution of the activity level of planet hosts.
Aims: We constrain the planetary atmospheric mass fraction at the time of the dispersa…
The rare X-ray flaring activity of the ultraluminous X-ray source NGC 4559 X7
Salvaterra, R.; Wolter, A.; Pintore, Fabio +9 more
Ultraluminous X-ray sources are considered amongst the most extremely accreting objects in the local Universe. The recent discoveries of pulsating neutron stars in ULXs strengthened the scenario of highly super-Eddington accretion mechanisms on stellar mass compact objects. In this work, we present the first long-term light curve of the source NGC…
Ultracool dwarfs in deep extragalactic surveys using the virtual observatory: ALHAMBRA and COSMOS
Béjar, V. J. S.; Martín, E. L.; Huélamo, N. +8 more
Ultracool dwarfs (UCDs) encompass a wide variety of compact stellar-like objects with spectra classified as late-M, L, T, and Y. Most of them have been discovered using wide-field imaging surveys. The Virtual Observatory (VO) has proven to be of great utility to efficiently exploit these astronomical resources. We aim to validate a VO methodology …
Mysterious, variable, and extremely hot: White dwarfs showing ultra-high excitation lines. I. Photometric variability
Pelisoli, Ingrid; Reindl, Nicole; Schaffenroth, Veronika +3 more
Context. About 10% of all stars exhibit absorption lines of ultra-highly excited (UHE) metals (e.g., O VIII) in their optical spectra when entering the white dwarf cooling sequence. This is something that has never been observed in any other astrophysical object, and poses a decades-long mystery in our understanding of the late stages of stellar e…
Contemporaneous Multiwavelength and Precovery Observations of the Active Centaur P/2019 LD2 (ATLAS)
Woodney, Laura M.; Volk, Kathryn; Kareta, Theodore +10 more
The Gateway Centaur and Jupiter co-orbital P/2019 LD2 (ATLAS) provides the first opportunity to observe the migration of a solar system small body from a Centaur orbit to a Jupiter Family Comet (JFC) four decades from now. The Gateway transition region is beyond where water ice can power cometary activity, and coma production there is as poorly un…
Detecting Biosignatures in the Atmospheres of Gas Dwarf Planets with the James Webb Space Telescope
Kendrew, Sarah; Hu, Renyu; Valenti, Jeff +5 more
Exoplanets with radii between those of Earth and Neptune have stronger surface gravity than Earth, and can retain a sizable hydrogen-dominated atmosphere. In contrast to gas giant planets, we call these planets gas dwarf planets. The James Webb Space Telescope (JWST) will offer unprecedented insight into these planets. Here, we investigate the det…
Stellar Spins in the Pleiades, Praesepe, and M35 Open Clusters
Schlaufman, Kevin C.; Healy, Brian F.; McCullough, P. R.
We analyze spectroscopic and photometric data to determine the projected inclinations of stars in three open clusters: the Pleiades, Praesepe, and M35. We determine the $\sin i$ values of 42, 35, and 67 stars in each cluster, respectively, and from their distributions we find that isotropic spins and moderate alignment are both consistent with the…
Balmer continuum enhancement detected in a mini flare observed with IRIS
Heinzel, Petr; Schmieder, Brigitte; Joshi, Reetika +3 more
Context. Optical and near-UV continuum emissions in flares contribute substantially to the flare energy budget. Two mechanisms play an important role for continuum emission in flares: hydrogen recombination after sudden ionization at chromospheric layers, and transportation of the energy radiatively from the chromosphere to lower layers in the atm…
The Consistency of Chemical Clocks among Coeval Stars
Jofré, Paula; Chanamé, Julio; Casamiquela, Laia +1 more
The abundance ratios of some chemical species have been found to correlate with stellar age, leading to the possibility of using stellar atmospheric abundances as stellar age indicators. These chemical clocks have already been calibrated with solar twins and open clusters, but it remains to be seen whether they can be effective at identifying coev…