- ID:
- ivo://CDS.VizieR/J/MNRAS/461/3296
- Title:
- Long-term core-collapse supernova simulations
- Short Name:
- J/MNRAS/461/3296
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The next Galactic supernova is expected to bring great opportunities for the direct detection of gravitational waves (GW), full flavour neutrinos, and multiwavelength photons. To maximize the science return from such a rare event, it is essential to have established classes of possible situations and preparations for appropriate observations. To this end, we use a long-term numerical simulation of the core-collapse supernova (CCSN) of a 17M_{sun}_ red supergiant progenitor to self-consistently model the multimessenger signals expected in GW, neutrino, and electromagnetic messengers. This supernova model takes into account the formation and evolution of a protoneutron star, neutrino-matter interaction, and neutrino transport, all within a two-dimensional shock hydrodynamics simulation. With this, we separately discuss three situations: (i) a CCSN at the Galactic Center, (ii) an extremely nearby CCSN within hundreds of parsecs, and (iii) a CCSN in nearby galaxies within several Mpc. These distance regimes necessitate different strategies for synergistic observations. In a Galactic CCSN, neutrinos provide strategic timing and pointing information. We explore how these in turn deliver an improvement in the sensitivity of GW analyses and help to guarantee observations of early electromagnetic signals. To facilitate the detection of multimessenger signals of CCSNe in extremely nearby and extragalactic distances, we compile a list of nearby red supergiant candidates and a list of nearby galaxies with their expected CCSN rates. By exploring the sequential multimessenger signals of a nearby CCSN, we discuss preparations for maximizing successful studies of such an unprecedented stirring event.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/548/A90
- Title:
- Looking for the rainbow on exoplanets
- Short Name:
- J/A+A/548/A90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Looking for the primary rainbow in starlight that is reflected by exoplanets appears to be a promising method to search for liquid water clouds in exoplanetary atmospheres. Ice water clouds, that consist of water crystals instead of water droplets, could potentially mask the rainbow feature in the planetary signal by covering liquid water clouds. Here, we investigate the strength of the rainbow feature for exoplanets that have liquid and icy water clouds in their atmosphere, and calculate the rainbow feature for a realistic cloud coverage of Earth. We calculate flux and polarization signals of starlight that is reflected by horizontally and vertically inhomogeneous Earth-like exoplanets, covered by patchy clouds consisting of liquid water droplets or water ice crystals. The planetary surfaces are black.
- ID:
- ivo://CDS.VizieR/J/A+A/587/A48
- Title:
- Lowell Photometric Database asteroid models
- Short Name:
- J/A+A/587/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Information about shapes and spin states of individual asteroids is important for the study of the whole asteroid population. For asteroids from the main belt, most of the shape models available now have been reconstructed from disk-integrated photometry by the lightcurve inversion method. We want to significantly enlarge the current sample (~350) of available asteroid models. We use the lightcurve inversion method to derive new shape models and spin states of asteroids from the sparse-in-time photometry compiled in the Lowell Photometric Database. To speed up the time-consuming process of scanning the period parameter space through the use of convex shape models, we use the distributed computing project Asteroids@home, running on the Berkeley Open Infrastructure for Network Computing (BOINC) platform. This way, the period-search interval is divided into hundreds of smaller intervals. These intervals are scanned separately by different volunteers and then joined together. We also use an alternative, faster, approach when searching the best-fit period by using a model of triaxial ellipsoid. By this, we can independently confirm periods found with convex models and also find rotation periods for some of those asteroids for which the convex-model approach gives too many solutions.
- ID:
- ivo://CDS.VizieR/J/A+A/617/A57
- Title:
- Lowell Photometric Database asteroid models. II.
- Short Name:
- J/A+A/617/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Information about the spin state of asteroids is important for our understanding of the dynamical processes affecting them. However, spin properties of asteroids are known for only a small fraction of the whole population. To enlarge the sample of asteroids with a known rotation state and basic shape properties, we combined sparse-in-time photometry from the Lowell Observatory Database with flux measurements from NASA's WISE satellite. We applied the light curve inversion method to the combined data. The thermal infrared data from WISE were treated as reflected light because the shapes of thermal and visual light curves are similar enough for our purposes. While sparse data cover a wide range of geometries over many years, WISE data typically cover an interval of tens of hours, which is comparable to the typical rotation period of asteroids. The search for best-fitting models was done in the framework of the Asteroids@home distributed computing project. By processing the data for almost 75000 asteroids, we derived unique shape models for about 900 of them. Some of them were already available in the DAMIT database and served us as a consistency check of our approach. In total, we derived new models for 662 asteroids, which significantly increased the total number of asteroids for which their rotation state and shape are known. For another 789 asteroids, we were able to determine their sidereal rotation period and estimate the ecliptic latitude of the spin axis direction. We studied the distribution of spins in the asteroid population. Apart from updating the statistics for the dependence of the distribution on asteroid size, we revealed a significant discrepancy between the number of prograde and retrograde rotators for asteroids smaller than about 10km. Combining optical photometry with thermal infrared light curves is an efficient approach to obtaining new physical models of asteroids. The amount of asteroid photometry is continuously growing and joint inversion of data from different surveys could lead to thousands of new models in the near future.
- ID:
- ivo://CDS.VizieR/J/A+A/547/A96
- Title:
- Low-mass He-core white dwarfs seismic properties
- Short Name:
- J/A+A/547/A96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present detailed tabulations of stellar models and pulsational properties for low-mass He-core white dwarf stars, for different stellar masses and effective temperatures. Pulsation periods were computed for g- and p-modes with harmonic degree l=1. The stellar mass ranges from 0.17M_{sun} to 0.45M_{sun}, while the effective temperature ranges from 13000 to 8000K. The pulsation periods are listed in files named ava_m.mmm_g.tgz and ava_m.mmm_p.tgz, for g- and p-modes, respectively, were m.mmm denotes the stellar mass in solar mass units. These files contain a sequence of tables (avannn_m.mmm_g.out and avannn_m.mmm_p.out) corresponding to models with decreasing effective temperature, where nnn correspond to the number of file, starting with nnn=001. In each avannn_m.mmm_g.out and avannn_m.mmm_p.out files, the following quantities are listed: harmonic degree (l), radial order (k), Period, period spacing (DP), kinetic energy (log(Ek)) and first order rotation splitting coefficient (C_kl). The stellar parameters characterizing each model are listed at the top of the table as a header: stellar mass in solar units (M_*/M_{sun}), luminosity in solar units (L_*/L_{sun}), effective temperature in Kelvin (Teff[K]), hydrogen mass in units of the stellar mass (log(M_H/M_*)), age in millions of years (Time [10^6^yr]), and asymptotic period spacing in seconds (DPa [s], for g-modes only). The chemical profiles and critical frequencies are listed in the files par_m.mmm.tgz, which contain a sequence of tables corresponding to models with decreasing effective temperature (parnnn_m.mmm.out). Stellar parameters of each model are listed as a header: stellar mass in solar units (M_*/M_{sun}), effective temperature in Kelvin (Teff[K]), luminosity in solar units (L_*/L_{sun}) and hydrogen mass in units of stellar mass (log(M_H/M_*)). Below the header, the following quantities are listed: normalized radial coordinate (r/R_*), the outer mass fraction coordinate (-log q, with q=1-M_r/M_*), the squared Brunt-Vaisala (N^2^) and Lamb (L^2^) frequencies, the Ledoux term (B Ledoux), and the abundances by mass of hydrogen (H1), helium (He4), carbon (C12) and oxygen (O16).
- ID:
- ivo://CDS.VizieR/J/A+A/595/A35
- Title:
- Low-mass helium white dwarfs evolutionary models
- Short Name:
- J/A+A/595/A35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large number of extremely low-mass helium white dwarfs (ELM WDs) have been discovered in recent years. The majority of them are found in close binary systems suggesting they are formed either through a common-envelope phase or via stable mass transfer in a low-mass X-ray binary (LMXB) or a cataclysmic variable (CV) system. Here, we investigate the formation of these objects through the LMXB channel with emphasis on the proto-WD evolution in environments with different metallicities. We study for the first time the combined ects of rotational mixing and element diffusion (e.g. gravitational settling, thermal and chemical diffusion) on the evolution of proto-WDs and on the cooling properties of the resulting WDs. We present state-of-the-art binary stellar evolution models computed with MESA for metallicities of Z=0.02, 0.01, 0.001 and 0.0002, producing WDs with masses between ~0.16-0.45M_{sun}_. Our results confirm that element diffusion plays a significant role in the evolution of proto-WDs that experience hydrogen shell flashes. The occurrence of these flashes produces a clear dichotomy in the cooling timescales of ELM WDs, which has important consequences e.g. for the age determination of binary millisecond pulsars. In addition, we confirm that the threshold mass at which this dichotomy occurs depends on metallicity. Rotational mixing is found to counteract the effect of gravitational settling in the surface layers of young, bloated ELM proto-WDs and therefore plays a key role in determining their surface chemical abundances, i.e. the observed presence of metals in their atmospheres. We predict that these proto-WDs have helium-rich envelopes through a significant part of their lifetime. This is of great importance as helium is a crucial ingredient in the driving of the {kappa}-mechanism suggested for the newly observed ELM proto-WD pulsators. However, we find that the number of hydrogen shell flashes and, as a result, the hydrogen envelope mass at the beginning of the cooling track, are not influenced significantly by rotational mixing. In addition to being dependent on proto-WD mass and metallicity, the hydrogen envelope mass of the newly formed proto-WDs depends on whether or not the donor star experiences a temporary contraction when the H-burning shell crosses the hydrogen discontinuity left behind by the convective envelope. The hydrogen envelope at detachment, although small compared to the total mass of the WD, contains enough angular momentum such that the spin frequency of the resulting WD on the cooling track is well above the orbital frequency.
347. Low-mass stars
- ID:
- ivo://CDS.VizieR/J/A+A/285/473
- Title:
- Low-mass stars
- Short Name:
- J/A+A/285/473
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/337/403
- Title:
- Low-mass stars evolutionary models
- Short Name:
- J/A+A/337/403
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Physical properties and absolute magnitudes of low-mass stars for different initial metallicity [M/H], helium mass fraction Y and mixing length parameter Lmix: mass (in solar mass), age (in Gyrs) effective temperature (in K), log of gravity (in cgs) and absolute magnitudes. The VRI magnitudes are in the Johnson-Cousins system and the JHK magnitudes in the CIT system. Note that the bolometric magnitude corresponds to M_bol(Sun)=4.64. The lowest mass corresponds to the hydrogen-burning limit.
- ID:
- ivo://CDS.VizieR/J/A+AS/141/371
- Title:
- Low-mass stars evolutionary tracks & isochrones
- Short Name:
- J/A+AS/141/371
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- These files contain a large database of stellar models that are suitable to modelling star clusters and galaxies by means of population synthesis. They are based on a large grid of stellar evolutionary tracks for the initial chemical compositions [Z=0.0004, Y=0.23], [Z=0.001, Y=0.23], [Z=0.004, Y=0.24], [Z=0.008, Y=0.25], [Z=0.019, Y=0.273] (solar composition), and [Z=0.03, Y=0.30]. Tracks are computed with updated opacities and equation of state, and a moderate amount of convective overshoot. The range of initial masses goes from 0.15M_{sun}_ to 7M_{sun}_, and the evolutionary phases extend from the zero age main sequence (ZAMS) till either the thermally pulsing AGB regime or carbon ignition. We also present an additional set of models with solar composition, computed using the classical Schwarzschild's criterion for convective boundaries. From all these models, we derive: (1) Tables with the main quantities that characterize the stellar structure along the evolutionary tracks; (2) tables of surface chemical composition after the first and second dredge-up events; (3) extended theoretical isochrones in the Johnson-Cousins UBVRIJHK broad-band photometric system, together with summary tables; (4) integrated colours of single-burst stellar populations.
- ID:
- ivo://CDS.VizieR/J/A+A/631/A77
- Title:
- Low-mass stellar models and isochrones
- Short Name:
- J/A+A/631/A77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an extended grid of state-of-the art stellar models for low-mass stars including updated physics (nuclear reaction rates, surface boundary condition, mass-loss rate, angular momentum transport, rotation-induced mixing, and torque prescriptions). We evaluate the impact of wind braking, realistic atmospheric treatment, rotation, and rotation-induced mixing on the structural and rotational evolution from the pre-main sequence (PMS) to the turn-off. Using the STAREVOL code, we provide an updated PMS grid. We computed stellar models for seven different metallicities, from [Fe/H]=-1dex to [Fe/H]=+0.3dex with a solar composition corresponding to Z=0.0134. The initial stellar mass ranges from 0.2 to 1.5M_{sun}_ with extra grid refinement around one solar mass. We also provide rotating models for three different initial rotation rates (slow, median, and fast) with prescriptions for the wind braking and disc-coupling timescale calibrated on observed properties of young open clusters. The rotational mixing includes the most recent description of the turbulence anisotropy in stably stratified regions. The overall behaviour of our models at solar metallicity, and their constitutive physics, are validated through a detailed comparison with a variety of distributed evolutionary tracks. The main differences arise from the choice of surface boundary conditions and initial solar composition. The models including rotation with our prescription for angular momentum extraction and self-consistent formalism for angular momentum transport are able to reproduce the rotation period distribution observed in young open clusters over a wide range of mass values. These models are publicly available and can be used to analyse data coming from present and forthcoming asteroseismic and spectroscopic surveys such as Gaia, TESS, and PLATO.The overall behaviour of our models at solar metallicity, and their constitutive physics, are validated through a detailed comparison with a variety of distributed evolutionary tracks. The main differences arise from the choice of surface boundary conditions and initial solar composition. The models including rotation with our prescription for angular momentum extraction and self-consistent formalism for angular momentum transport are able to reproduce the rotation period distribution observed in young open clusters over a wide range of mass values. These models are publicly available and can be used to analyse data coming from present and forthcoming asteroseismic and spectroscopic surveys such as Gaia, TESS, and PLATO.
