Xu, S.; Rappaport, S.; van Lieshout, R.; Vanderburg, A.; Gary, B.; Hallakoun, N.; Ivanov, V. D.; Wyatt, M. C.; DeVore, J.; Bayliss, D.; Bento, J.; Bieryla, A.; Cameron, A.; Cann, J. M.; Croll, B.; Collins, K. A.; Dalba, P. A.; Debes, J.; Doyle, D.; Dufour, P.; Ely, J.; Espinoza, N.; Joner, M. D.; Jura, M.; Kaye, T.; McClain, J. L.; Muirhead, P.; Palle, E.; Panka, P. A.; Provencal, J.; Randall, S.; Rodriguez, J. E.; Scarborough, J.; Sefako, R.; Shporer, A.; Strickland, W.; Zhou, G.; Zuckerman, B.
Monthly Notices of the Royal Astronomical Society, Volume 474, Issue 4, p.4795-4809
White dwarf WD 1145+017 is orbited by several clouds of dust, possibly
emanating from actively disintegrating bodies. These dust clouds reveal
themselves through deep, broad, and evolving transits in the star's
light curve. Here, we report two epochs of multiwavelength photometric
observations of WD 1145+017, including several filters in the optical,
Ks and 4.5 μm bands in 2016 and 2017. The observed transit
depths are different at these wavelengths. However, after correcting for
excess dust emission at Ks and 4.5 μm, we find the transit
depths for the white dwarf itself are the same at all wavelengths, at
least to within the observational uncertainties of ˜5-10 per cent.
From this surprising result, and under the assumption of low optical
depth dust clouds, we conclude that there is a deficit of small
particles (with radii s ≲ 1.5 μm) in the transiting material. We
propose a model wherein only large particles can survive the high
equilibrium temperature environment corresponding to 4.5 h orbital
periods around WD 1145+017, while small particles sublimate rapidly. In
addition, we evaluate dust models that are permitted by our measurements
of infrared emission.
Exoplanets and Astrobiology
The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable