During the last decades, growing evidence about the presence of planetary material around white dwarfs has been established. The features of heavy elements in the spectra of a large fraction (25-50%) of these objects needs a frequent accretion of material orbiting close to the white dwarf. Additionally, at least 4% of these objects are known to host dusty disks. The space mission K2, that re-uses the Kepler instrument after a failure of two of its four gyroscopes, recently detected transiting material around WD1145+017, with periods in the 4.5-5h range, and a depth variability with scales of a few days. This is attributed to the presence of disintegrating planetesimals, due to the high temperatures close to the white dwarf. The K2 data suffer from a poor sampling to study this object (30 min), and they lack chromatic information. In this work, we used the IAC80 telescope to predict deep transits that were observed a few hours later with OSIRIS at GTC. The close to 1-min sampling, and the information in four visible bands, allowed for the first detection, with an unprecedented precision, of the color of the transiting material. The lack of depth changes in the different bands (gray transits) served to set constraints to the minimal particle sizes of the transiting material, which have to be 0.5 microns or larger for the most common minerals.
Advertised on
References
It may interest you
-
Stellar ages are key to several fields of astrophysics such as exoplanet research, galactic-archeology, and of course stellar physics. Obtaining the ages of stars is however not straightforward and requires stellar modeling. The most widely used technique only requires stellar colors or temperature and surface gravity, but the uncertainties are quite large. This technique is most efficient for stars belonging to clusters, as they were born from the same molecular cloud and share the same ages. In the last decades, based on the study of stellar acoustic waves, asteroseismology became the mostAdvertised on
-
The amount and complexity of data delivered by modern galaxy surveys has been steadily increasing over the past years. New facilities will soon provide imaging and spectra of hundreds of millions of galaxies. Extracting coherent scientific information from these large and multi-modal data sets remains an open issue for the community and data-driven approaches such as deep learning have rapidly emerged as a potentially powerful solution to some long lasting challenges. This enthusiasm is reflected in an unprecedented exponential growth of publications using neural networks, which have goneAdvertised on
-
Dark matter is an invisible substance that makes up more than eighty percent of the matter content of the universe. We know of its existence due to its gravitational influence, being a key ingredient to understand everything from the large-scale evolution of the universe to the formation of galaxies like the Milky Way, of which we are part of . However, very little is known about its nature, which constitutes one of the greatest unsolved problems in contemporary physics. The fuzzy dark matter model has recently been studied as a promising candidate. In this model , it is postulated that darkAdvertised on