- ID:
- ivo://CDS.VizieR/J/AJ/129/856
- Title:
- Herbig Ae/Be stars in nearby OB associations
- Short Name:
- J/AJ/129/856
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a study of the early-type stars in nearby OB associations spanning an age range of ~3-16Myr, with the aim of determining the fraction of stars that belong to the Herbig Ae/Be class. We studied the B, A, and F stars in the nearby (<=500pc) OB associations Upper Scorpius, Perseus OB2, Lacerta OB1, and Orion OB1, with membership determined from Hipparcos (Cat. <I/239>) data. We also included in our study the early-type stars in the Trumpler 37 cluster, part of the Cep OB2 association. We obtained spectra for 440 Hipparcos stars in these associations, from which we determined accurate spectral types, visual extinctions, effective temperatures, luminosities and masses, using Hipparcos photometry.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/453/976
- Title:
- Herbig Ae/Be X-shooter observations
- Short Name:
- J/MNRAS/453/976
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Herbig Ae/Be stars (HAeBes) span a key mass range that links low- and high-mass stars, and thus provide an ideal window from which to explore their formation. This paper presents Very Large Telescope/X-shooter spectra of 91 HAeBes, the largest spectroscopic study of HAeBe accretion to date. A homogeneous approach to determining stellar parameters is undertaken for the majority of the sample. Measurements of the ultraviolet are modelled within the context of magnetospheric accretion, allowing a direct determination of mass accretion rates. Multiple correlations are observed across the sample between accretion and stellar properties: the youngest and often most massive stars are the strongest accretors, and there is an almost 1:1 relationship between the accretion luminosity and stellar luminosity. Despite these overall trends of increased accretion rates in HAeBes when compared to classical T Tauri stars, we also find noticeable differences in correlations when considering the Herbig Ae and Herbig Be subsets. This, combined with the difficulty in applying a magnetospheric accretion model to some of the Herbig Be stars, could suggest that another form of accretion may be occurring within Herbig Be mass range.
- ID:
- ivo://nasa.heasarc/hbc
- Title:
- Herbig&BellCatalogofOrionPop.Emission-LineStars
- Short Name:
- HBC
- Date:
- 11 Oct 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table contains the Third Catalog of Emission-Line Stars of the Orion Population (Herbig and Bell (1988)) which lists 735 pre-main sequence stars, members of the Orion Population, that have been observed with slit spectrographs or at equivalent resolution. It is intended to replace the Second Catalog of Herbig and Rao (1972). It gives accurate coordinates (many determined especially for this Catalog); light ranges for known variables; UBVRI data near maximum light; references to ultraviolet, X-ray, and radio observations, and to light curves; value of v sin i and the radial velocity when known; spectral type; equivalent width of the H-alpha emission line; references to spectral reproductions or scans and spectroscopic studies and to identification charts; and a classification (as a T Tau star, FU Ori object, etc.). This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/A+A/475/281
- Title:
- Herbig-Haro flows in B335
- Short Name:
- J/A+A/475/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aim is to study the Herbig-Haro flows in the nearby dark globule B335, to find new HH objects and H2 knots, make a proper motion map of the flow activity and investigate physical properties through shock models.
- ID:
- ivo://CDS.VizieR/J/A+A/658/A5
- Title:
- Hercules A LOFAR and JVLA images
- Short Name:
- J/A+A/658/A5
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The prominent radio source Hercules A features complex structures in its radio lobes. Despite being one of the most comprehensively studied sources in the radio sky, the origin of the ring structures in the Hercules A radio lobes remains an open question. We present the first sub-arcsecond angular resolution images at low frequencies (<300MHZ) of Hercules A, made with the International LOFAR Telescope. With the addition of data from the Karl G. Jansky Very Large Array, we map the structure of the lobes from 144MHz to 7GHz. We explore the origin of the rings within the lobes of Hercules A, and test whether their properties are best described by a shock model where shock waves are produced by the jet propagating in the radio lobe, or an inner-lobe model in which the rings are formed by decelerated jetted plasma. From spectral index mapping, our large frequency coverage reveals that the curvature of the different ring spectra increases with distance away from the central active galactic nucleus. We demonstrate that the spectral shape of the rings is consistent with synchrotron aging, which speaks in favor of an inner-lobe model, where the rings are formed from the deposition of material from past periods of intermittent core activity.
- ID:
- ivo://CDS.VizieR/IV/26
- Title:
- Hercules Messier 13 (M13) photometry
- Short Name:
- IV/26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ludendorff's catalog of the M13 globular cluster results from observations made with the 32.5cm refractor of Potsdam Observatory, one on 17 July 1900 (plate A), and the second on June 1902 (plate B). Each plate was measured twice, in opposite position, to remove the possible errors. The catalog contains accurate positions on both plates, photographic magnitudes, and comparison with the previous results from Scheiner (1892). Number 1119 to 1127 where seen only in one position on plate A, and in two positions on plate B. Number 1128 to 1136 where seen only on plate A, and are not in Scheiner catalog.
- ID:
- ivo://CDS.VizieR/J/MNRAS/460/1356
- Title:
- Hercules stream K giants analysis
- Short Name:
- J/MNRAS/460/1356
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An abundance analysis is reported of 58-K giants identified by Famaey et al. (2005, J/A+A/430/165) as highly probable members of the Hercules stream selected from stars north of the celestial equator in the Hipparcos catalogue. The giants have compositions spanning the interval [Fe/H] from -0.17 to +0.42 with a mean value of +0.15 and relative elemental abundances [El/Fe] representative of the Galactic thin disc. Selection effects may have biased the selection from the Hipparcos catalogue against the selection of metal-poor stars. Our reconsideration of the recent extensive survey by Bensby et al. of FG dwarfs, including metal-poor stars, provides a [Fe/H] distribution for the Hercules stream, which is similar to that from the 58 giants. It appears that the stream is dominated by metal-rich stars from the thin disc. We discuss suggestions in the literature that the stream includes metal-poor stars from the thick disc.
- ID:
- ivo://CDS.VizieR/J/AJ/115/6
- Title:
- Hercules supercluster kinematics
- Short Name:
- J/AJ/115/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Hercules supercluster consists of the Abell clusters A2147, A2151, and A2152. Previous studies of the kinematics have been confounded by the difficulty of correctly assigning galaxies to the individual clusters, which are not well separated. Our study has a total of 468 available velocities for galaxies in the region, 175 of them new. There are 414 galaxies in the supercluster, about 3 times the number used in the previous supercluster study. We verify the existence of the three individual clusters and compute their individual dynamical parameters. We investigate several techniques for assigning galaxy membership to clusters in this crowded field. We use the Kaye's mixture model (Ashman, Bird, & Zepf, 1994AJ....108.2348A) algorithm to separate the galaxies into clusters; we find that A2152 has a higher mean velocity than previous studies have reported. A2147 and A2152 also have lower velocity dispersions: 821^+68^_-55_ and 715^+81^_-61_km/s, respectively. The assignment of galaxies to either A2152 or A2147 requires velocity and position information. We study the kinematics of the supercluster using the two-body formalism of Beers, Geller, & Huchra (1982ApJ...257...23B) and conclude that A2147 and A2151 are probably bound to each other and that the supercluster as a whole may also be bound. The mass of the supercluster, if bound, is (7.6+/-2.0)x10^15^h^-1^M_{sun}_; with the supercluster luminosity, (1.4+/-0.2)x10^13^h^-2^L_{sun}_, this yields {OMEGA}=0.34+/-0.1.
- ID:
- ivo://CDS.VizieR/J/A+A/439/129
- Title:
- HERES II. Spectroscopic analysis
- Short Name:
- J/A+A/439/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of analysis of "snapshot" spectra of 253 metal-poor halo stars -3.8<=[Fe/H]<=-1.5 obtained in the HERES survey. The snapshot spectra have been obtained with VLT/UVES and have typically S/N~54 per pixel (ranging from 17 to 308), R~20000, lambda=3760-4980{AA}. This sample represents the major part of the complete HERES sample of 373 stars; however, the CH strong content of the sample is not dealt with here.
- ID:
- ivo://CDS.VizieR/J/A+A/528/A92
- Title:
- HERES VI. Galactic chemical evolution of Si and C
- Short Name:
- J/A+A/528/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To obtain detailed silicon abundances of metal-poor stars, we aim to explore the correlation between the abundance ratios and the stellar parameters and the chemical enrichment of the interstellar medium (ISM). We determined the silicon abundances of 253 metal-poor stars in the metallicity range -4<[Fe/H]<-1.5, based on non-local thermodynamic equilibrium (NLTE) line formation calculations of neutral silicon and high-resolution spectra obtained with VLT-UT2/UVES.