scholarly journals A multifrequency study of the active star-forming complex NGC 6357 - I. Interstellar structures linked to the open cluster Pis 24

2011 ◽  
Vol 415 (3) ◽  
pp. 2844-2858 ◽  
Author(s):  
C. E. Cappa ◽  
R. Barbá ◽  
N. U. Duronea ◽  
J. Vasquez ◽  
E. M. Arnal ◽  
...  
Keyword(s):  
Open Cluster ◽  
Active Star ◽  
Star Forming

scholarly journals SEJONG OPEN CLUSTER SURVEY (SOS) - V. THE ACTIVE STAR FORMING REGION SH 2-255 - 257

2015 ◽  
Vol 48 (6) ◽  
pp. 343-355 ◽  
Author(s):  
BEOMDU LIM ◽  
HWANKYUNG SUNG ◽  
HYEONOH HUR ◽  
BYEONG-CHEOL LEE ◽  
MICHAEL S. BESSELL ◽  
...  
Keyword(s):  
Open Cluster ◽  
Active Star ◽  
Star Forming ◽  
Cluster Survey

scholarly journals Small Galactic Nebulae

1987 ◽  
Vol 115 ◽  
pp. 191-192
Author(s):  
Yervant Terzian ◽  
Kenneth C. Turner
Keyword(s):  
High Resolution ◽  
Planetary Nebula ◽  
Physical Parameters ◽  
H Ii Regions ◽  
Radio Observations ◽  
Cluster Emission ◽  
Active Star ◽  
Star Forming ◽  
Cometary Nebula ◽  
Significant Flux

We have performed high resolution VLA radio observations for several small H II regions, including the cluster emission nebulae S258, S255, S257, and S256. The region (PP56) between S255 and S257 at λ2 cm reveals significant flux structure close to OH, H2O and infrared emitting sources as shown in Figure 1. The flux densities and positions are indicated in Table 1. Observations of the cometary nebula PP59 (S269) also reveal similar characteristics as shown in Figure 2. These regions are considered to be active star-forming clouds. The cometary nebula PP40 was also observed and we note that its physical parameters are very similar to those of a typical planetary nebula.

scholarly journals A multifrequency study of the active star forming region NGC 6357

2006 ◽  
Vol 2 (S237) ◽  
pp. 400-400
Author(s):  
C. E. Cappa ◽  
R. H. Barbá ◽  
M. Arnal ◽  
N. Duronea ◽  
E. Fernández Lajús ◽  
...  
Keyword(s):  
Angular Resolution ◽  
Massive Stars ◽  
Radio Continuum ◽  
Large Array ◽  
Schmidt Telescope ◽  
Ionized Gas ◽  
Very Large Array ◽  
Active Star ◽  
Star Forming ◽  
Spiral Arm

To investigate the interaction of the massive stars with the gas and dust in the active star forming region NGC 6357, located in the Sagittarius spiral arm at a distance of 1.7-2.6 kpc (Massey et al. 2001), we analyzed the distribution of the neutral and ionized gas, and that of the dust, based on Hα, [OIII] and [SII] images obtained with the Curtis-Schmidt telescope at CTIO, radio continuum observations at 1.465 MHz obtained with the Very Large Array (NRAO) in the DnC configuration (synthesized beam = 38″), Hi data from the Parkes survey (angular resolution = 15′), CO(1-0) observations obtained with the Nanten radiotelescope at Las Campanas Observatory (angular resolution = 2.7′), and IR images in the four MSX bands (angular resolution = 18.3″).

scholarly journals Structure and Mass Function of Open Cluster NGC 6910

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Harmeen Kaur ◽  
Saurabh Sharma ◽  
Alok K. Durgapal
Keyword(s):  
Molecular Clouds ◽  
Luminosity Function ◽  
Open Cluster ◽  
Mass Function ◽  
Open Clusters ◽  
Initial Mass Function ◽  
Wide Field ◽  
Evolutionary Models ◽  
Star Forming ◽  
Initial Results

NGC 6910 is located in a Cygnus X region, which is a ∼10◦ complex of actively star forming molecular clouds and young clusters, located at a distance of about 1.7 kpc (Reipurth & Schneider 2008). Open clusters possess many favorable characteristics for initial mass function (IMF) studies. The observed mass function of a star cluster can in principle be determined from the observed luminosity function (LF) using theoretical stellar evolutionary models. Here, we are presenting our initial results related to structure parameters, extinction, distance and mass function of open cluster NGC 6910 based on the deep and wide field mosaic images taken from 1.0m Sampurnand telescope of ARIES, India.

scholarly journals Structure and Mass Function of Open Cluster NGC 6910

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Harmeen Kaur ◽  
Saurabh Sharma ◽  
Alok K. Durgapal
Keyword(s):  
Molecular Clouds ◽  
Luminosity Function ◽  
Open Cluster ◽  
Mass Function ◽  
Open Clusters ◽  
Initial Mass Function ◽  
Wide Field ◽  
Evolutionary Models ◽  
Star Forming ◽  
Initial Results

NGC 6910 is located in a Cygnus X region, which is a ∼10◦ complex of actively star forming molecular clouds and young clusters, located at a distance of about 1.7 kpc (Reipurth & Schneider 2008). Open clusters possess many favorable characteristics for initial mass function (IMF) studies. The observed mass function of a star cluster can in principle be determined from the observed luminosity function (LF) using theoretical stellar evolutionary models. Here, we are presenting our initial results related to structure parameters, extinction, distance and mass function of open cluster NGC 6910 based on the deep and wide field mosaic images taken from 1.0m Sampurnand telescope of ARIES, India

scholarly journals Radial velocity confirmation of K2-100b: a young, highly irradiated, and low-density transiting hot Neptune

2019 ◽  
Vol 490 (1) ◽  
pp. 698-708 ◽  
Author(s):  
O Barragán ◽  
S Aigrain ◽  
D Kubyshkina ◽  
D Gandolfi ◽  
J Livingston ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Detailed Analysis ◽  
Mass Measurement ◽  
Open Cluster ◽  
Low Density ◽  
Active Star ◽  
Process Framework ◽  
Young Open Cluster ◽  
High Level ◽  
Validation Tests

ABSTRACT We present a detailed analysis of HARPS-N radial velocity observations of K2-100, a young and active star in the Praesepe cluster, which hosts a transiting planet with a period of 1.7 d. We model the activity-induced radial velocity variations of the host star with a multidimensional Gaussian Process framework and detect a planetary signal of 10.6 ± 3.0 ${\rm m\, s^{-1}}$, which matches the transit ephemeris, and translates to a planet mass of 21.8 ± 6.2 M⊕. We perform a suite of validation tests to confirm that our detected signal is genuine. This is the first mass measurement for a transiting planet in a young open cluster. The relatively low density of the planet, $2.04 _{ - 0.61 } ^ { + 0.66 }$ ${\rm g\, cm^{-3}}$, implies that K2-100b retains a significant volatile envelope. We estimate that the planet is losing its atmosphere at a rate of $10^{11}\!-\!10^{12}\, {\rm g\, s^{-1}}$ due to the high level of radiation it receives from its host star.

Diffuse star-forming galaxies: thermal emission in radio continuum at 1.4 GHz

2018 ◽  
pp. 21-23
Author(s):  
S. Parnovsky ◽  
I. Izotova
Keyword(s):  
Star Formation ◽  
Radio Emission ◽  
Emission Line ◽  
Equivalent Width ◽  
Colour Index ◽  
Thermal Component ◽  
Active Star ◽  
Star Forming ◽  
Active Star Formation ◽  
Thermal Radio Emission

We determine the fraction of thermal radio emission in the total flux at the frequency of 1.4 GHz in 30 diffuse star-forming galaxies using the approach described in the paper by Parnovsky and Izotova (Astronomische Nachrichten, 2015 Vol.336, Issue 3, p.276). We use the sample of diffuse galaxies with active star formation selected from the Data Release 12 (DR12) of the Sloan Digital Sky Survey (SDSS). The SDSS spectroscopic data for diffuse galaxies were supplemented by radio data from the FIRST and NVSS catalogues. From the fluxes in the Hβ emission line corrected for extinction and aperture we estimate the fluxes of thermal component of the radio emission at the 1.4 GHz using the result of the paper by J. Caplan and L. Deharveng (Astron. Astrophys. 1986, V. 155, P.297) and compare them with total fluxes from the FIRST and NVSS. In the sample of diffuse galaxies with active star formation, the distribution of the fraction of thermal radio emission A is similar to the lognormal one with the median value of 6 %. This is less than the median value which was derived earlier by Parnovsky and Izotova for a sample of compact star-forming galaxies, but both distributions of A are similar. We study the dependence of A on the W equivalent width of the Hβ emission line and on the I colour index g-r. The fraction of thermal component increases with increasing of the equivalent width of the Hβ emission line if a colour index is constant or an increasing of the colour index at a fixed equivalent width W.

scholarly journals Dust cleansing of star-forming gas

2018 ◽  
Vol 616 ◽  
pp. A91 ◽  
Author(s):  
Bengt Gustafsson
Keyword(s):  
Small Groups ◽  
Open Cluster ◽  
Momentum Conservation ◽  
Giant Molecular Clouds ◽  
Early Type ◽  
Star Forming ◽  
Neutral Gas ◽  
H Ii Region ◽  
Early Type Stars ◽  
The Rich

Aims. We explore the possibility that solar chemical composition, as well as the similar composition of the rich open cluster M 67, have been affected by dust cleansing of the presolar or precluster cloud due to the radiative forces from bright early-type stars in its neighbourhood. Methods. We estimate possible cleansing effects using semi-analytical methods, which are essentially based on momentum conservation. Results. Our calculations indicate that the amounts of cleansed neutral gas are limited to a relatively thin shell surrounding the H II region around the early-type stars. Conclusions. It seems possible that the proposed mechanism acting in individual giant molecular clouds may produce significant abundance effects for masses corresponding to single stars or small groups of stars. The effects of cleansing are, however, severely constrained by the thinness of the cleansed shell of gas and by turbulence in the cloud. This is why the mechanism can hardly be important in cleansing masses corresponding to rich clusters, such as the mass of the original M 67.

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