Time-resolved photometry of the young dipper RX~J1604.3-2130A:Unveiling the structure and mass transport through the innermost disk

Context. RX J1604.3-2130A is a young, dipper-type, variable star in the Upper Scorpius association, suspected to have an inclined inner disk, with respect to its face-on outer disk. Aims. We aim to study the eclipses to constrain the inner disk properties. Methods. We used time-resolved photometry from the Rapid Eye Mount telescope and Kepler 2 data to study the multi-wavelength variability, and archival optical and infrared data to track accretion, rotation, and changes in disk structure. Results. The observations reveal details of the structure and matter transport through the inner disk. The eclipses show 5 d quasi-periodicity, with the phase drifting in time and some periods showing increased/decreased eclipse depth and frequency. Dips are consistent with extinction by slightly processed dust grains in an inclined, irregularly-shaped inner disk locked to the star through two relatively stable accretion structures. The grains are located near the dust sublimation radius (similar to 0.06 au) at the corotation radius, and can explain the shadows observed in the outer disk. The total mass (gas and dust) required to produce the eclipses and shadows is a few % of a Ceres mass. Such an amount of mass is accreted/replenished by accretion in days to weeks, which explains the variability from period to period. Spitzer and WISE infrared variability reveal variations in the dust content in the innermost disk on a timescale of a few years, which is consistent with small imbalances (compared to the stellar accretion rate) in the matter transport from the outer to the inner disk. A decrease in the accretion rate is observed at the times of less eclipsing variability and low mid-IR fluxes, confirming this picture. The v sin i = 16 km s(-1) confirms that the star cannot be aligned with the outer disk, but is likely close to equator-on and to be aligned with the inner disk. This anomalous orientation is a challenge for standard theories of protoplanetary disk formation.Science & Technology Facilities Council (STFC): ST/S000399/1. ESO fellowship. European Union (EU): 823 823. German Research Foundation (DFG): FOR 2634/1 TE 1024/1-1. French National Research Agency (ANR): ANR-16-CE31-0013. Alexander von Humboldt Foundation. European Research Council (ERC): 678 194. European Research Council (ERC): 742 095. National Aeronautics & Space Administration (NASA). National Science Foundation (NSF). National Aeronautics & Space Administration (NASA): NNG05GF22G. National Science Foundation (NSF): AST-0909182, AST-1 313 422

The Effect Of Regional Original Revenue, General Allocation Funds, And Special Allocation Funds On Economic Growth In The North Sulawesi Province

The authority received by local governments from the regional autonomy system in order to collect and distribute funds independently as well as decide on development interests. Regional autonomy seeks to equalize growth/development in accordance with regional interests in order to increase regional development based on the capabilities of each region.The purpose behind this study is to analyze the effects of Regional Original Revenue (PAD), General Allocation Fund (DAU), and Special Allocation Fund (DAK) on economic growth in North Sulawesi Province. This study uses a collection of period series information for some time, 2002-2021 to be precise. Multiple linear regression analysis method was used in this research. The results of the research findings show that: 1) PAD has no substantial influence on economic growth in North Sulawesi Province; 2) DAU has a positive but insignificant impact on economic growth in North Sulawesi Province; 3) DAK has a negative effect on economic growth in North Sulawesi Province; 4) Meanwhile, simultaneously PAD, DAU and DAK have a positive and substantial effect on economic growth in North Sulawesi Province. In addition to the effort to increase the value of regional income indicators, improving the quality of human resources (HR) as managers of indicators in sustainable regional autonomy policies is one of the important efforts for the implementation of regional autonomy to support regional economic growth

MBM 12: young protoplanetary discs at high galactic latitude

(abridged) We present Spitzer infrared observations to constrain disc and dust evolution in young T Tauri stars in MBM 12, a star-forming cloud at high latitude with an age of 2 Myr and a distance of 275 pc. The region contains 12 T Tauri systems, with primary spectral types between K3 and M6; 5 are weak-line and the rest classical T Tauri stars. We first use MIPS and literature photometry to compile spectral energy distributions for each of the 12 members in MBM 12, and derive their IR excesses. The IRS spectra are analysed with the newly developed two-layer temperature distribution (TLTD) spectral decomposition method. For the 7 T Tauri stars with a detected IR excess, we analyse their solid-state features to derive dust properties such as mass-averaged grain size, composition and crystallinity. We find a spatial gradient in the forsterite to enstatite range, with more enstatite present in the warmer regions. The fact that we see a radial dependence of the dust properties indicates that radial mixing is not very efficient in the discs of these young T Tauri stars. The SED analysis shows that the discs in MBM 12, in general, undergo rapid inner disc clearing, while the binary sources have faster discevolution. The dust grains seem to evolve independently from the stellar properties, but are mildly related to disc properties such as flaring and accretion rates.Comment: 14 pages, accepted by Astronomy and Astrophysic

Geometry of phase separation

We study the domain geometry during spinodal decomposition of a 50:50 binary mixture in two dimensions. Extending arguments developed to treat non-conserved coarsening, we obtain approximate analytic results for the distribution of domain areas and perimeters during the dynamics. The main approximation is to regard the interfaces separating domains as moving independently. While this is true in the non-conserved case, it is not in the conserved one. Our results can therefore be considered as a first-order approximation for the distributions. In contrast to the celebrated Lifshitz-Slyozov-Wagner distribution of structures of the minority phase in the limit of very small concentration, the distribution of domain areas in the 50:50 case does not have a cut-off. Large structures (areas or perimeters) retain the morphology of a percolative or critical initial condition, for quenches from high temperatures or the critical point respectively. The corresponding distributions are described by a $c A^{-\tau}$ tail, where $c$ and $\tau$ are exactly known. With increasing time, small structures tend to have a spherical shape with a smooth surface before evaporating by diffusion. In this regime the number density of domains with area $A$ scales as $A^{1/2}$, as in the Lifshitz-Slyozov-Wagner theory. The threshold between the small and large regimes is determined by the characteristic area, ${\rm A} \sim [\lambda(T) t]^{2/3}$. Finally, we study the relation between perimeters and areas and the distribution of boundary lengths, finding results that are consistent with the ones summarized above. We test our predictions with Monte Carlo simulations of the 2d Ising Model.Comment: 10 pages, 8 figure

A network of filaments detected by Herschel in the Serpens core : a laboratory to test simulations of low-mass star formation

V.R. was partly supported by the DLR grant number 50 OR 1109 and by the Bayerische Gleichstellungsförderung (BGF). This research was partly supported by the Priority Programme 1573 “Physics of the Interstellar Medium” of the German Science Foundation (DFG), the DFG cluster of excellence “Origin and Structure of the Universe” and by the Italian Ministero dell’Istruzione, Università e Ricerca through the grant Progetti Premiali 2012 -iALMA (CUP C52I13000140001). C.E. is partly supported by Spanish Grants AYA 2011-26202 and AYA 2014-55840-P.Context. Filaments represent a key structure during the early stages of the star formation process. Simulations show that filamentary structures commonly formed before and during the formation of cores. Aims. The Serpens core is an ideal laboratory for testing the state of the art of simulations of turbulent giant molecular clouds. Methods. We used Herschel observations of the Serpens core to compute temperatureand column density maps of the region. We selected the early stages of are cent simulation of star-formation, before stellar feedback was initiated, with similar total mass and physical size as the Serpens core. We also derived temperature and column density maps from the simulations. The observed distribution of column densities of the filaments was analyzed, first including and then masking the cores. The same analysis was performed on the simulations as well. Results. A radial network of filaments was detected in the Serpens core. The analyzed simulation shows a striking morphological resemblance to the observed structures. The column density distribution of simulated filaments without cores shows only a log-normal distribution, while the observed filaments show a power-law tail. The power-law tail becomes evident in the simulation if the focus is only the column density distribution of the cores. In contrast, the observed cores show a flat distribution. Conclusions. Even though the simulated and observed filaments are subjectively similar-looking, we find that they behave in very different ways. The simulated filaments are turbulence-dominated regions; the observed filaments are instead self-gravitating structures that will probably fragment into cores.Publisher PDFPeer reviewe

Accretion through the inner hole of transitional disks: What happens to the dust?

We study the effect of radiation pressure on the dust in the inner rim of transitional disks with large inner holes. In particular, we evaluate whether radiation pressure can be responsible for keeping the inner holes dust-free, while allowing gas accretion to proceed. This has been proposed in a paper by Chiang and Murray-Clay (2007, Nature Physics 3, p. 604) who explain the formation of these holes as an inside-out evacuation due to X- ray-triggered accretion of the innermost layer of the disk rim outside of the hole. We show that radiation pressure is clearly incapable of stopping dust from flowing into the hole because of dust pile-up and optical depth effects, and also because of viscous mixing. Other mechanisms need to be found to explain the persistence of the opacity hole in the presence of accretion, and we speculate on possible solutions.Comment: 6 pages, 3 figures, Accepted for publication by Astronomy and Astrophysic