Dust Structure Nearby G229-03

The Sky View Virtual Observatory was used for the systematic search of dust structures within the far-infrared loop G229-03. The source (object) responsible for the formation of the cavity of interest was detected by the Set of Identifications, Measurements, and Bibliography for Astronomical Data (SIMBAD) database. The total mass of the loop was 8.50031 × 1029 kg which is about 0.425 times the mass of the Sun at a distance of 1300 pc. The size of the cavity was 3.67° × 3.6°, whereas its core size was 0.531° × 0.255° located at R.A. (J2000) = 7h10m0.8s and Dec.(J2000) =15h55m30s. The minimum and maximum temperatures were between 20.24 ± 1.16 K and 18.63 ± 1.96 K respectively. In the core region, the average temperature was 19.53 K, approximately equal to Gaussian center 19.267 K with an offset temperature of 0.4 K showing that the core region of the cavity is dynamically stable. The Far-infrared loop was found to be located within a 1° radius around the high-velocity cloud HVC oriented by 45° to the plane of the sky. The inclination angle of the core of the loop was greater than 60° whereas the inclination angle for the larger structure was 13.71°. The Gaussian distribution of temperature was well fitted with the center of 19.267 K which shows that the cavity was in thermal equilibrium and the outer region with offset temperature of about 35 K suggesting that the loop was dynamically unstable possibly due to high-velocity cloud

Optimizing the structure of a dust concentration measuring device

The particle movement speed in the pipe of an existing dust measuring device is too small, and the detection in the center area of the pipe is not sufficiently sensitive. According to the intake mode of the cyclone separator, here a new side inlet pipeline is designed that is oriented from the incident mode of the straight pipe. An experimental model was established in Gambit2.4, and the numerical simulation was performed in Fluent6.3. Different dust particle diameters were simulated, and velocity cloud and pressure cloud diagrams of the middle position of the device pipe were obtained. Compared with the velocity data of the straight tube and the side tube, the velocity value of the particle passing through the side tube was better than that of the straight tube. This improved the velocity of the particles and also reduced the settling of the particles. The probability of friction collision of the dust particles in the tube increased, meaning that their induced charge also increased. MATLAB was used to calculate the electrostatic induction, revealing that the charge of the particles in the improved device increased significantly. Therefore, the improved device can effectively improve the measurement accuracy of dust at low concentrations, and for small particle sizes.

Young stars raining through the galactic halo: the nature and orbit of price-whelan 1

ABSTRACT We present radial velocities for five member stars of the recently discovered young (age ≃ 100−150 Myr) stellar system Price-Whelan 1 (PW 1), which is located far away in the Galactic Halo (D≃ 29 kpc, Z≃ 15 kpc), and that is probably associated with the leading arm (LA) of the Magellanic Stream. We measure the systemic radial velocity of PW 1, Vr = 275 ± 10 km s−1, significantly larger than the velocity of the LA gas in the same direction. We re-discuss the main properties and the origin of this system in the light of these new observations, computing the orbit of the system and comparing its velocity with that of the H i in its surroundings. We show that the bulk of the gas at the velocity of the stars is more than 10 deg (5 kpc) away from PW 1 and the velocity difference between the gas and the stars becomes larger as gas closer to the stars is considered. We discuss the possibilities that (1) the parent gas cloud was dissolved by the interaction with the Galactic gas, and (2) that the parent cloud is the high-velocity cloud (HVC) 287.5+22.5 + 240, lagging behind the stellar system by ≃ 25 km s−1 and ≃10 deg ≃ 5 kpc. This HVC, which is part of the LA, has metallicity similar to PW 1, displays a strong magnetic field that should help to stabilize the cloud against ram pressure, and shows traces of molecular hydrogen. We also show that the system is constituted of three distinct pieces that do not differ only by position in the sky but also by stellar content.