相关论文: Dusty Cometary Globules in W5

The zodiacal cloud is a thick circumsolar disk of small debris particles produced by asteroid collisions and comets. Here, we present a zodiacal cloud model based on the orbital properties and lifetimes of comets and asteroids, and on the…

Molecular clouds at very high latitudes ($b > 60^o$) away from the Galactic plane are considered rare and not conventional sites of star formation. Contrary to this, the recent discovery of high latitude embedded Clusters can possibly…

We have used the Keck I telescope to image at 11.7 microns and 17.9 microns the dust emission around zeta Lep, a main sequence A-type star at 21.5 pc from the Sun with an infrared excess. The excess is at most marginally resolved at 17.9…

A dense-enough gas-accumulation evolves, over a few Myr of intensifying star formation, to an embedded cluster. If it contains a sufficient amount of mass, O stars form and explosively expel the remaining gas, whereas poorer clusters reduce…

In a multi-wavelength survey of $13$ quasars at $5.8\lesssim z\lesssim6.5$, that were pre-selected to be potentially young, we find five objects with extremely small proximity zone sizes that may imply UV-luminous quasar lifetimes of…

In recent years, the number of white dwarfs (WDs) showing infrared (IR) excesses, attributed to circumstellar dust disks, has grown significantly. Gaseous disks have also been detected in some WDs with dust. We obtained optical spectra with…

We present the discovery of a spatially unresolved source of sub-millimeter continuum emission ($\lambda=855$ $\mu$m) associated with a young planet, PDS 70 c, recently detected in H$\alpha$ emission around the 5 Myr old T Tauri star PDS…

Starless dense cores eventually collapse dynamically, which forms protostars inside them, and the physical properties of the cores determine the nature of the forming protostars. We report ALMA observations of dust continuum emission and…

Young stars are surrounded by copious amounts of circumstellar material. Its composition, in particular its gas-to-dust ratio, is an important parameter. However, measuring this ratio is challenging, because gas mass estimates are often…

We present high spatial resolution Submillimeter Array observations and supplementary single-dish photometry of the molecular gas and dust around IRAS 04158+2805, a young source with spectral type M5-M6 in the Taurus star-forming region. A…

(Abridged) The c2d Spitzer Legacy project obtained images and photometry with both IRAC and MIPS instruments for five large, nearby molecular clouds. This paper combines information drawn from studies of individual clouds into a combined…

The formation timescale and final architecture of exoplanetary systems are closely related to the properties of the molecular disks from which they form. Observations of the spatial distribution and lifetime of the molecular gas at…

Stars form in regions of the galaxy that are denser and cooler than the mean interstellar medium. These regions are called Giant Molecular Clouds. At the beginning of their life, up to $10^5-10^6$ years, stars accrete matter from their rich…

It is speculated that some weakly active comets may be transitional objects between active and dormant comets. These objects are at a unique stage of the evolution of cometary nuclei, as they are still identifiable as active comets, in…

We conducted radio observations searching for OH 18-cm maser emission from a sample of 169 unclassified MIPSGAL compact Galactic bubbles. These sources are thought to be the circumstellar envelopes of different kinds of evolved stars. Our…

Using recently acquired HST NIR observations (J, Pa$\beta$ and H bands) of the nearby galaxy NGC1313, we investigate the timescales required by a young star cluster to emerge from its natal cloud. We search for extincted star clusters,…

Large dust reservoirs (up to $\sim 10^8 \, \mathrm{M_\odot}$) have been detected in galaxies out to redshift $z \sim 8$, when the age of the universe was only about 600 Myr. Generating significant amounts of dust within such a short…

Dusty discs detected around main-sequence stars are thought to be signs of planetesimal belts in which the dust distribution is shaped by collisional and dynamical processes, including interactions with gas if present. The debris disc…

Using wide-field photometric data from the Sloan Digital Sky Survey (SDSS) we recently showed that the Galactic globular cluster Palomar 5 is in the process of being tidally disrupted. Its tidal tails were initially detected in a 2.5 degree…

Multi-wavelength images from the Hubble Space Telescope covering the wavelength range 0.27-1.6 $\mu$m show that the central area of the nearby dwarf galaxy NGC4449 contains several tens of compact sources that are emitting in the hydrogen…