- ID:
- ivo://CDS.VizieR/III/205
- Title:
- H-alpha Stars in Northern Milky Way
- Short Name:
- III/205
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The catalogue contains 4174 stars in the Northern Milky Way, in the range 32{deg}<l<214{deg}, -10{deg}<b<+10{deg}, having the H line in emission. The HBH list (main list, Schmidt camera Hamburg-Bergedorf, red plates taken in the years 1964-70) contains 1979 objects partly identical with those in other lists of H emission-line stars given in the literature up till 1994. Non-stellar objects (e.g. HII regions, planetary nebulae) have not been included in this catalogue except for those objects containing central stars which have the H line in emission, and also for some doubtful cases.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/624/A33
- Title:
- HD 100453 AB system ALMA images
- Short Name:
- J/A+A/624/A33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The complex system HD 100453 AB with a ring-like circumprimary disk and two spiral arms, one of which is pointing to the secondary, is a good laboratory in which to test spiral formation theories. We aim to resolve the dust and gas distribution in the disk around HD 100453 A and to quantify the interaction of HD 100453 B with the circumprimary disk. Using ALMA band 6 dust continuum and CO isotopologue observations we have studied the HD 100453 AB system with a spatial resolution of 0.09"x0.17" at 234GHz. We used smoothed particle hydrodynamics (SPH) simulations and orbital fitting to investigate the tidal influence of the companion on the disk. We resolve the continuum emission around HD 100453 A into a disk between 0.22" and 0.40" with an inclination of 29.5{deg} and a position angle of 151.0{deg}, an unresolved inner disk, and excess mm emission cospatial with the northern spiral arm which was previously detected using scattered light observations. We also detect CO emission from 7au (well within the disk cavity) out to 1.10", overlapping with HD 100453 B at least in projection. The outer CO disk position angle (PA) and inclination dier by up to 10{deg} from the values found for the inner CO disk and the dust continuum emission, which we interpret as due to gravitational interaction with HD 100453 B. Both the spatial extent of the CO disk and the detection of mm emission at the same location as the northern spiral arm are in disagreement with the previously proposed near co-planar orbit of HD 100453 B. We conclude that HD 100453 B has an orbit that is significantly misaligned with the circumprimary disk. Because it is unclear whether such an orbit can explain the observed system geometry we highlight an alternative scenario that explains all detected disk features where another, (yet) undetected, low mass close companion within the disk cavity, shepherds a misaligned inner disk whose slowly precessing shadows excite the spiral arms.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A94
- Title:
- HD141569A system ALMA and NOEMA data cubes
- Short Name:
- J/A+A/635/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of gas-rich debris discs is fundamental to characterising the transition between protoplanetary discs and debris discs. Aims. We determine the physical parameters of the brightest gas-rich debris disc orbiting HD 141569A. We analyse images from the NOrthern Extended Millimeter Array (NOEMA) and the Atacama Large Millimeter/submillimeter Array (ALMA) in ^12^CO, ^13^CO J=2-1, and ^13^CO J=1-0 transitions. We incorporate ALMA archival data of the ^12^CO J=3-2 transition and present continuum maps at 0.87mm, 1.3mm, and 2.8mm. We use simple parametric laws with the Diskfit code and MCMC exploration to characterise the gas disc parameters and report a first attempt to characterise its chemical content with IRAM-30m. The continuum emission is equally shared between a compact (<50au) and a smooth, extended dust component (~350 au). Large millimetre grains seem to dominate the inner regions, while the dust spectral index is marginally larger in the outer region. The ^12^CO is optically thick, while ^13^CO is optically thin with tau_13CO_~0.15 (C^18^O is not detected). The ^13^CO surface density is constrained to be one order of magnitude smaller than around younger Herbig Ae stars, and we derive a gas mass M_12CO_=10^-1^M_{sun}_. We confirm the presence of a small CO cavity (R_CO_=17+/-3au), and find a possibly larger radius for the optically thin ^13^CO J=2-1 transition (35+/-5au). We show that the observed CO brightness asymmetry is coincident with the complex ring structures discovered with VLT/SPHERE in the inner 90au. The ^12^CO temperature T_0_(100au)~30K is lower than expected for a Herbig~A0 star, and could be indicative of subthermal excitation. With the largest amount of dust and gas among hybrid discs, HD141569A shows coincident characteristics of both protoplanetary discs (central regions), and debris discs at large distance. Together with its morphological characteristics and young age, it appears to be a good candidate to witness the transient phase of gas dissipation, with an apparently large gas-to-dust ratio (G/D>100) favouring a faster evolution of dust grains.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A95
- Title:
- HD160305 images with SPHERE
- Short Name:
- J/A+A/626/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Direct imaging of debris disks gives important information about their nature, their global morphology and allows to identify specific structures possibly in connection with the presence of gravitational perturbers. It is the most straightforward technique to observe planetary systems as a whole. We present the first resolved images of the debris disk around the young F-type star HD 160305, detected in scattered light using the VLT/SPHERE instrument in the near infrared. We used a post-processing method based on Angular Differential Imaging and synthetic images of debris disks produced with a disk modeling code (GRaTer) to constrain the main characteristics of the disk around HD160305. All of the point sources in the field of the IRDIS camera were analyzed with an astrometric tool to determine whether they are bound objects or background stars. We detect a very inclined (~82{deg}) ring-like debris disk located at a stellocentric distance of about 86au (deprojected width ~27au). The disk displays a brightness asymmetry between the two sides of the major axis, as can be expected from scattering properties of dust grains. We derive an anisotropic scattering factor g>0.5. A second right-left asymmetry is also observed with respect to the minor axis. We measure a surface brightness ratio of 0.73+/-0.18 between the bright and the faint sides. Because of the low signal-to-noise ratio (S/N) of the images we cannot easily discriminate between several possible explanations for this left-right asymmetry, such as perturbations by an unseen planet, the aftermath of the breakup of a massive planetesimal, or the pericenter glow effect due to an eccentric ring. Two epochs of observations allow us to reject the companionship hypothesis for the 15 point sources present in the field.
- ID:
- ivo://CDS.VizieR/J/A+A/648/A110
- Title:
- HD142527 SPHERE polarimetric images
- Short Name:
- J/A+A/648/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-precision photometry and polarimetry based on visual and near-infrared imaging data for the protoplanetary disk surrounding the Herbig Ae/Be star HD 142527, with a strong focus on determining the light scattering parameters of the dust located at the surface of the large outer disk. We re-reduced existing polarimetric differential imaging data of HD 142527 in the VBB (735nm) and H-band (1625nm) from the ZIMPOL and IRDIS subinstruments of SPHERE at the VLT. With polarimetry and photometry based on reference star differential imaging (RDI), we were able to measure the linearly polarized intensity and the total intensity of the light scattered by the circumstellar disk with high precision. We used simple Monte Carlo simulations of multiple light scattering by the disk surface to derive constraints for three scattering parameters of the dust: the maximum polarization of the scattered light Pmax, the asymmetry parameter g, and the single-scattering albedo {omega}. We measure a reflected total intensity of 51.4+/-1.5mJy and 206+/-12mJy and a polarized intensity of 11.3+/-0.3mJy and 55.1+/-3.3mJy in the VBB and H-band, respectively. We also find in the visual range a degree of polarization that varies between 28% on the far side of the disk and 17% on the near side. In the H-band, the degree of polarization is consistently higher by about a factor of 1.2. The disk also shows a red color for the scattered light intensity and the polarized intensity, which are about twice as high in the near-infrared when compared to the visual. We determine with model calculations the scattering properties of the dust particles and find evidence for strong forward scattering (g {prop.to} 0.5-0.75), relatively low single-scattering albedo ({omega} {prop.to} 0.2-0.5), and high maximum polarization (Pmax {prop.to} 0.5-0.75) at the surface on the far side of the disk for both observed wavelengths. The optical parameters indicate the presence of large aggregate dust particles, which are necessary to explain the high maximum polarization, the strong forward-scattering nature of the dust, and the observed red disk color.
- ID:
- ivo://CDS.VizieR/J/MNRAS/493/234
- Title:
- Herbig Ae/Be accretion rates & mechanisms
- Short Name:
- J/MNRAS/493/234
- Date:
- 02 Feb 2022 07:28:24
- Publisher:
- CDS
- Description:
- This work presents a spectroscopic study of 163 Herbig Ae/Be stars. Amongst these, we present new data for 30 objects. Stellar parameters such as temperature, reddening, mass, luminosity, and age are homogeneously determined. Mass accretion rates are determined from H{alpha} emission line measurements. Our data is complemented with the X-Shooter sample from previous studies and we update results using Gaia DR2 parallaxes giving a total of 78 objects with homogeneously determined stellar parameters and mass accretion rates. In addition, mass accretion rates of an additional 85 HAeBes are determined. We confirm previous findings that the mass accretion rate increases as a function of stellar mass, and the existence of a different slope for lower and higher mass stars, respectively. The mass where the slope changes is determined to be 3.98^+1.37_-0.94M_{sun}_. We discuss this break in the context of different modes of disc accretion for low- and high-mass stars. Because of their similarities with T Tauri stars, we identify the accretion mechanism for the late-type Herbig stars with the Magnetospheric Accretion. The possibilities for the earlier-type stars are still open, we suggest the Boundary Layer accretion model may be a viable alternative. Finally, we investigated the mass accretion-age relationship. Even using the superior Gaia based data, it proved hard to select a large enough sub-sample to remove the mass dependence in this relationship. Yet, it would appear that the mass accretion does decline with age as expected from basic theoretical considerations.
- ID:
- ivo://CDS.VizieR/J/AJ/118/1043
- Title:
- Herbig Ae/Be stars catalog
- Short Name:
- J/AJ/118/1043
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVR photometric monitoring of Herbig Ae/Be stars and some related objects has been carried out at Maidanak Observatory in Uzbekistan since 1983. More than 71,000 observations of about 230 stars have been obtained and are made available for anonymous ftp. Virtually all Herbig Ae/Be stars observed are irregular variables (called "UXors" after UX Ori), but there is a wide range of amplitudes from barely detectable to more than 4mag in V. Our data confirm the results of previous studies, which indicate that large-amplitude variability is confined to stars with spectral types later than B8. The distribution of variability ranges is quite similar to what is seen in classical T Tauri stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/300/779
- Title:
- High-latitude H-alpha emission stars
- Short Name:
- J/ApJ/300/779
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Approximately 1300 5.2x5.2deg^2^ red-sensitive objective prism plates have been searched for H{alpha}-emission stars in order to complete the search of the entire sky. The survey here reported represents 59% of the whole sky, defined by the region north of declination -25{deg} and mostly further than 10{deg} from the Galactic plane; the omitted portions had already been surveyed, in part at Warner and Swasey, in part elsewhere. Two hundred and six stars have been newly found, mostly of unknown spectral type. The stars' latitude distribution suggest that they are mainly moderately high luminosity disk population stars. There are new finds especially in Orion and the Taurus dark clouds (limiting mag ~13).
- ID:
- ivo://CDS.VizieR/J/AJ/112/1188
- Title:
- HK survey emission-line candidates
- Short Name:
- J/AJ/112/1188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a list of 218 additional candidate emission-line objects discovered with the northern and southern HK interference-filter/ objective-prism survey of Beers and collaborators. The objects have apparent magnitudes in the range 10<=B<=16, several magnitudes fainter than obtained with previous prism surveys of similar resolution. Of the new candidates, 73 have been previously identified. The total list of HK-survey emission-line candidates now numbers 376 objects, 104 of which were noted by previous surveys.
- ID:
- ivo://CDS.VizieR/J/AJ/108/268
- Title:
- HK survey emission-line candidates positions
- Short Name:
- J/AJ/108/268
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents a list of 158 candidate emission-line objects detected with the northern HK interference-filter/objective-prism survey obtained with the Burrell Schmidt telescope. The objects have magnitudes in the range 11=<B=<15.5, several magnitudes fainter than obtained with prism surveys of similar resolution. (The HK filter restricts the passband to the region around the H and K lines of Ca II)
