相关论文: NGC 6994 - clearly not a physical stellar ensemble

Star clusters represent the most common 'mode' of star formation. They are found in all types of environments, cascading down from galaxy groups and merging pairs through starbursts to normal galaxies and dwarves and even isolated regions…

We consider the possibility of cluster membership for 13 planetary nebulae that are located in close proximity to open clusters lying in their lines of sight. The short lifetimes and low sample size of intermediate-mass planetary nebulae…

The characteristics of ionized and HI gas in the peculiar star/cluster complex in NGC 6946, obtained with the 6-m telescope (BTA) SAO RAS, the Gemini North telescope, and the Westerbork Synthesis Radio Telescope (WSRT), are presented. The…

We use available multifilter Hubble Space Telescope (HST) WFPC2 imaging of five (M81, M83, NGC 6946, M101, and M51) low inclination, nearby spiral galaxies to study ancient star cluster populations. M81 globular clusters (GC) have an…

We search for hints to the origin and nature of compact stellar systems in the magnitude range of ultracompact dwarf galaxies in deep wide-field imaging data of the Fornax cluster core. We visually investigate a large sample of 355…

As Be stars are restricted to luminosity classes III-V, but early B-type stars are believed to evolve into supergiants, it is to be expected that the Be phenomenon disappears at some point in the evolution of a moderately massive star,…

We have analyzed OGLE-III photometry for stars in the SMC cluster NGC 299. Two eclipsing binaries and one intrinsic variable (most likely a Be star) are identified. Unlike other young SMC clusters, no low-amplitude pulsating variables are…

We have obtained deep photometry of NGC 1199 (in the compact group HCG 22) and NGC 6868 (in the Telescopium loose group) with the Keck II and the VLT-I telescopes. Both galaxies are the optically brightest galaxy of their groups. NGC 1199…

Since first noticed by Shapley in 1939, a faint object coincident with the Fornax dwarf spheroidal has long been discussed as a possible sixth globular cluster system. However, debate has continued over whether this overdensity is a…

We report on a UV-oriented imaging survey in the fields of the old, metal-rich open clusters, NGC 6791, NGC 6819 and NGC 7142. These three clusters represent both very near and ideal stellar aggregates to match the distinctive properties of…

We present results of our survey for planetary transits in the field of NGC 6940. We think nearly all of our observed stars are field stars. We have obtained high precision (3-10 millimags at the bright end) photometric observations of…

Compact relativistic stars allow us to study the nature of matter under extreme conditions, probing regions of parameter space that are otherwise inaccessible. Nuclear theory in this regime is not well constrained: one key issue is whether…

We are conducting a large program to classify newly discovered Milky Way star cluster candidates from the list of Froebrich, Scholz & Raftery (2007). Here we present deep NIR follow-up observations from ESO/NTT of 14 star cluster…

We present results of the search for variable stars in the field of young open cluster NGC 581. Based on 19 nights of observations, 6 new variable stars were discovered. Two of them turned out to be eclipsing binary systems. Another two…

NGC 2419 is a massive outer halo Galactic globular cluster whose stars have previously been shown to have somewhat peculiar abundance patterns. We have observed seven luminous giants that are members of NGC 2419 with Keck/HIRES at…

Radial velocities of 94 galaxies brighter than about V_tot = 20 mag in the direction of the central Fornax cluster have been measured. Except for 8 Fornax members, all galaxies lie in the background. Among the 8 members, there are 5…

Some extragalactic SNRs are more than two orders of magnitude more luminous than the young Galactic SNR Cas A. These SNRs are called super-luminous or ultra-luminous SNRs. Their high luminosities can be caused by chance superpositions of…

The relatively nearby spiral galaxy NGC~6946 is one of the most actively star forming galaxies in the local Universe. Ten supernovae (SNe) have been observed since 1917, and hence NGC6946 surely contains a large number of supernova remnants…

We reexamine the surface composition of strange stars. Strange quark stars are hypothetical compact stars which could exist if strange quark matter was absolutely stable. It is widely accepted that they are characterized by an enormous…

We report the discovery of 19 variable stars and two blue-stragglers in the field of the open cluster NGC6866. Three of the variable stars we classify as delta Sct, two, as gamma Dor, four, as WUMa, two, as ellipsoidal variables, and one,…