5 research outputs found
Glancing through the debris disk: Photometric analysis of DE Boo with CHEOPS
DE Boo is a unique system, with an edge-on view through the debris disk around the star. The disk, which is analogous to the Kuiper belt in the Solar System, was reported to extend from 74 to 84 AU from the central star. The high photometric precision of the Characterising Exoplanet Satellite (CHEOPS) provided an exceptional opportunity to observe small variations in the light curve due to transiting material in the disk. This is a unique chance to investigate processes in the debris disk. Photometric observations of DE Boo of a total of four days were carried out with CHEOPS. Photometric variations due to spots on the stellar surface were subtracted from the light curves by applying a two-spot model and a fourth-order polynomial. The photometric observations were accompanied by spectroscopic measurements with the 1m RCC telescope at Piszk\'estet\H{o} and with the SOPHIE spectrograph in order to refine the astrophysical parameters of DE Boo. We present a detailed analysis of the photometric observation of DE Boo. We report the presence of nonperiodic transient features in the residual light curves with a transit duration of 0.3-0.8 days. We calculated the maximum distance of the material responsible for these variations to be 2.47 AU from the central star, much closer than most of the mass of the debris disk. Furthermore, we report the first observation of flaring events in this system. We interpreted the transient features as the result of scattering in an inner debris disk around DE Boo. The processes responsible for these variations were investigated in the context of interactions between planetesimals in the system
Photometry and performance of SPECULOOS-South
SPECULOOS-South, an observatory composed of four independent 1m robotic
telescopes, located at ESO Paranal, Chile, started scientific operation in
January 2019. This Southern Hemisphere facility operates as part of SPECULOOS,
an international network of 1m-class telescopes surveying for transiting
terrestrial planets around the nearest and brightest ultra-cool dwarfs. To
automatically and efficiently process the observations of SPECULOOS-South, and
to deal with the specialised photometric requirements of ultra-cool dwarf
targets, we present our automatic pipeline. This pipeline includes an algorithm
for automated differential photometry and an extensive correction technique for
the effects of telluric water vapour, using ground measurements of the
precipitable water vapour. Observing very red targets in the near-infrared can
result in photometric systematics in the differential lightcurves, related to
the temporally-varying, wavelength-dependent opacity of the Earth's atmosphere.
These systematics are sufficient to affect the daily quality of the
lightcurves, the longer time-scale variability study of our targets and even
mimic transit-like signals. Here we present the implementation and impact of
our water vapour correction method. Using the 179 nights and 98 targets
observed in the I+z' filter by SPECULOOS-South since January 2019, we show the
impressive photometric performance of the facility (with a median precision of
~1.5 mmag for 30-min binning of the raw, non-detrended lightcurves) and assess
its detection potential. We compare simultaneous observations with
SPECULOOS-South and TESS, to show that we readily achieve high-precision,
space-level photometry for bright, ultra-cool dwarfs, highlighting
SPECULOOS-South as the first facility of its kind
Fundamental Physics with Brown Dwarfs: The Mass-Radius Relation
To be published in the Decadal Survey on Astronomy and Astrophysics (Astro2020)The lowest-mass stars, brown dwarfs and giant exoplanets span a minimum in the mass-radius relationship that probes the fundamental physics of extreme states of matter, magnetism, and fusion. This White Paper outlines scientific opportunities and the necessary resources for modeling and measuring the mass-radius relationship in this regime
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π Earth: A 3.14 day Earth-sized Planet from K2's Kitchen Served Warm by the SPECULOOS Team
π Earth: A 3.14 day Earth-sized Planet from K2's Kitchen Served Warm by the SPECULOOS Team
We report on the discovery of a transiting Earth-sized (0.95)
planet around an M3.5 dwarf star at 57pc, K2-315b. The planet has a period
of 3.14 days, i.e. , with an instellation of
7.45S. The detection was made using publicly available data from
's Campaign 15. We observed three additional transits with
SPECULOOS Southern and Northern Observatories, and a stellar spectrum from
Keck/HIRES, which allowed us to validate the planetary nature of the signal.
The confirmed planet is well suited for comparative terrestrial exoplanetology.
While exoplanets transiting ultracool dwarfs present the best opportunity for
atmospheric studies of terrestrial exoplanets with the , those orbiting mid-M dwarfs within 100pc such as K2-315b
will become increasingly accessible with the next generation of observatories