For decades ever since the early detection in the 1990s of the emission spectral features of crystalline silicates in oxygen-rich evolved stars, there is a long-standing debate on whether the crystallinity of the silicate dust correlates with the stellar mass-loss rate. To investigate the relation between the silicate crystallinities and the mass-loss rates of evolved stars, we carry out a detailed analysis of 28 nearby oxygen-rich stars. We derive the mass-loss rates of these sources by modelling their spectral energy distributions from the optical to the far-infrared. Unlike previous studies in which the silicate crystallinity was often measured in terms of the crystalline-to-amorphous silicate mass ratio, we characterize the silicate crystallinities of these sources with the flux ratios of the emission features of crystalline silicates to that of amorphous silicates. This does not require the knowledge of the silicate dust temperatures, which are the major source of uncertainties in estimating the crystalline-to-amorphous silicate mass ratio. With a Pearson correlation coefficient of ~-0.24, we find that the silicate crystallinities and the mass-loss rates of these sources are not correlated. This supports the earlier findings that the dust shells of low mass-loss rate stars can contain a significant fraction of crystalline silicates without showing the characteristic features in their emission spectra.
SimDAL Data Access service for AMES-cond evolutionary tracks
Short Name:
AMES-cond tck
Date:
14 Mar 2019 08:14:12
Publisher:
SVO CAB
Description:
SimDAL data access service for AMES-cond evolutionary tracks. Dust in equilibrium with gas phase, with dust opacities ignored, (only GNS1993 available) valid for Teff smaller than 1400 K
SimDAL Data Access service for AMES-cond isochrones
Short Name:
AMES-cond iso
Date:
14 Mar 2019 08:14:12
Publisher:
SVO CAB
Description:
SimDAL data access service for AMES-cond isochrones. Dust in equilibrium with gas phase, with dust opacities ignored, (only GNS1993 available) valid for Teff smaller than 1400 K
SimDAL Data Access service for AMES-dusty evolutionary tracks
Short Name:
AMES-dusty tck
Date:
14 Mar 2019 08:14:12
Publisher:
SVO CAB
Description:
SimDAL data access service for AMES-dusty evolutionary tracks. Dust in equilibrium with gas phase, (only GNS1993 available) valid for Near-IR studies with Teff larger than 1700 K
SimDAL Data Access service for AMES-dusty isochrones
Short Name:
AMES-dusty iso
Date:
14 Mar 2019 08:14:12
Publisher:
SVO CAB
Description:
SimDAL data access service for AMES-dusty isochrones. Dust in equilibrium with gas phase, (only GNS1993 available) valid for Near-IR studies with Teff larger than 1700 K
SimDAL Search service for AMES-cond isochrones and evolutionary tracks
Short Name:
AMES-cond iso
Date:
14 Mar 2019 08:14:12
Publisher:
SVO CAB
Description:
SimDAL search service for AMES-cond isochrones and evolutionary tracks. Dust in equilibrium with gas phase, with dust opacities ignored, (only GNS1993 available) valid for Teff smaller than 1400 K
SimDAL Search service for AMES-dusty isochrones and evolutionary tracks
Short Name:
AMES-dusty iso
Date:
14 Mar 2019 08:14:12
Publisher:
SVO CAB
Description:
SimDAL search service for AMES-dusty isochrones and evolutionary tracks. Dust in equilibrium with gas phase, (only GNS1993 available) valid for Near-IR studies with Teff larger than 1700 K
The Transiting Exoplanet Survey Satellite (TESS) has a goal of detecting small planets orbiting stars bright enough for mass determination via ground-based radial velocity observations. Here, we present estimates of how many exoplanets the TESS mission will detect, the physical properties of the detected planets, and the properties of the stars that those planets orbit. This work uses stars drawn from the TESS Input Catalog (TIC) Candidate Target List and revises yields from prior studies that were based on Galactic models. We modeled the TESS observing strategy to select approximately 200000 stars at 2-minute cadence, while the remaining stars are observed at 30-minute cadence in full-frame image data. We placed zero or more planets in orbit around each star, with physical properties following measured exoplanet occurrence rates, and used the TESS noise model to predict the derived properties of the detected exoplanets. In the TESS 2-minute cadence mode we estimate that TESS will find 1250+/-70 exoplanets (90% confidence), including 250 smaller than 2R_{Earth}_. Furthermore, we predict that an additional 3100 planets will be found in full-frame image data orbiting bright dwarf stars and more than 10000 around fainter stars. We predict that TESS will find 500 planets orbiting M dwarfs, but the majority of planets will orbit stars larger than the Sun. Our simulated sample of planets contains hundreds of small planets amenable to radial velocity follow-up, potentially more than tripling the number of planets smaller than 4R_{Earth}_ with mass measurements. This sample of simulated planets is available for use in planning follow-up observations and analyses.
We present the results of a study of synergies between space telescopes (HST, CHEOPS, TESS, JWST, PLATO) in the photometric characterization of the atmospheres of Hot Jupiters. We analyze a set of planetary systems hosting a Hot Jupiter for which an atmospheric template is available in literature. For each system, we simulate the transit light curves observed by different instruments, convolving the incoming spectrum with the corresponding instrumental throughput. For each instrument, we thus measure the expected transit depth and estimate the associated uncertainty. Finally, we compare the transit depths as seen by the selected instruments and we quantify the effect of the planetary atmosphere on multi-band transit photometry.
The intrinsic uncertainty (due to statistical effects) affecting the integrated colours and mass-to-light ratios as a function of the cluster's integrated visual magnitude (M_V^tot^_) is studied. We investigate the case of metal-poor, single-burst stellar populations with age from a few million years to a likely upper value for the Galactic globular cluster ages. Monte Carlo techniques are used for randomly generating stars distributed according to the cluster's mass function. Integrated colours and mass-to-light ratios in different photometric bands are presented as a function of age for different assumptions on the cluster total V magnitude and they are checked for good agreement with the observational values of low-metallicity Galactic clusters.