TOI-3235 b: a transiting giant planet around an M4 dwarf star

We present the discovery of TOI-3235 b, a short-period Jupiter orbiting an M-dwarf with a stellar mass close to the critical mass at which stars transition from partially to fully convective. TOI-3235 b was first identified as a candidate from TESS photometry, and confirmed with radial velocities from ESPRESSO, and ground-based photometry from HATSouth, MEarth-South, TRAPPIST-South, LCOGT, and ExTrA. We find that the planet has a mass of $\mathrm{0.665\pm0.025\,M_J}$ and a radius of $\mathrm{1.017\pm0.044\,R_J}$. It orbits close to its host star, with an orbital period of $\mathrm{2.5926\,d}$, but has an equilibrium temperature of $\mathrm{\approx 604 \, K}$, well below the expected threshold for radius inflation of hot Jupiters. The host star has a mass of $\mathrm{0.3939\pm0.0030\,M_\odot}$, a radius of $\mathrm{0.3697\pm0.0018\,R_\odot}$, an effective temperature of $\mathrm{3389 \, K}$, and a J-band magnitude of $\mathrm{11.706\pm0.025}$. Current planet formation models do not predict the existence of gas giants such as TOI-3235 b around such low-mass stars. With a high transmission spectroscopy metric, TOI-3235 b is one of the best-suited giants orbiting M-dwarfs for atmospheric characterization.Comment: 15 pages, 4 figures. Accepted for publication in APJ

The First Post-Kepler Brightness Dips of KIC 8462852

We present a photometric detection of the first brightness dips of the unique variable star KIC 8462852 since the end of the Kepler space mission in 2013 May. Our regular photometric surveillance started in October 2015, and a sequence of dipping began in 2017 May continuing on through the end of 2017, when the star was no longer visible from Earth. We distinguish four main 1-2.5% dips, named "Elsie," "Celeste," "Skara Brae," and "Angkor", which persist on timescales from several days to weeks. Our main results so far are: (i) there are no apparent changes of the stellar spectrum or polarization during the dips; (ii) the multiband photometry of the dips shows differential reddening favoring non-grey extinction. Therefore, our data are inconsistent with dip models that invoke optically thick material, but rather they are in-line with predictions for an occulter consisting primarily of ordinary dust, where much of the material must be optically thin with a size scale <<1um, and may also be consistent with models invoking variations intrinsic to the stellar photosphere. Notably, our data do not place constraints on the color of the longer-term "secular" dimming, which may be caused by independent processes, or probe different regimes of a single process

Segi praktis ilmu telinga - hidung - tenggorokan/ Moore-Gillon

vi, 156 hal.; ill.; 21,5 cm

Segi praktis ilmu telinga - hidung - tenggorokan/ Moore-Gillon

vi, 156 hal.; ill.; 21,5 cm

Dynamic Model of a Three-Phase Full-Bridge Inverter-Fed Switched Reluctance Motor for Optimization Purposes

A Permeance Netvvork Analysis (PNA) of the dynamic behavior of a three phase Switched Reluctance Motor fed from a full-bridge inverter is presented. The non-linear effects due to global and local saturation are taken into consideration as well as the mutual coupling between phases. All permeances in the magnetic circuit are analytically computed in order to reduce the overall computation time in view of a future integration with an optimization process. The switching technique is also integrated within the PNA model. A validation of the obtained results is provided using finite element analysis and experimental measurements

Life condition monitoring on smart power devices using a sequence of current and charge-based capacitance measurements

The precise life condition monitoring on smart power devices is important for smart power circuit design. To perform such a monitoring, a technique based on charge-based capacitance measurement has been developed, by which all DC, AC measurements and stress are implemented in sequence on a device. Measurement, stress and re-measurement are repeated on a logarithmic time sequence, and key parameters for the life condition monitoring are extracted from the measured curves. The degradation of the key parameters is characterized as a measure for the life condition monitoring. The technique is accurate, flexible and with lower cost