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71. Objective-prism survey of em. objects in M31
ID:
ivo://CDS.VizieR/J/A+AS/102/251
Title:
Objective-prism survey of em. objects in M31
Short Name:
J/A+AS/102/251
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using GRENS plates taken at the Canada-France-Hawaii telescope, we have searched almost the whole extent of M31 for small-diameter objects with strong emission lines. Most are planetary nebulae candidates, but there are also many Wolf-Rayet star candidates and small HII regions or compact parts of large HII regions. A catalogue is presented with a cross-identification with previous catalogues. Many new planetary nebulae and Wolf-Rayet candidates are found. Their distribution is compared with those of other tracers in M31. In particular the distribution of planetary nebulae candidates is compared with that of the integrated blue light and we confirm the result obtained by Jacoby ( 1980ApJS...42....1J) and Ciardullo et al. (1989ApJ...339...53C): the number of planetary nebulae per unit total luminosity is a constant throughout the disk of M31. The Wolf- Rayet star candidates are concentrated in the well-known ring of star formation; their total number is estimated as 300 within the limit of detection of the deepest existing surveys, but this may still be an underestimate of the true number.
72. ONC binary and triple stars
ID:
ivo://CDS.VizieR/J/A+A/627/A57
Title:
ONC binary and triple stars
Short Name:
J/A+A/627/A57
Date:
21 Oct 2021
Publisher:
CDS
Description:
Recently published high-quality OmegaCAM photometry of the 3x3deg around the Orion Nebula Cluster (ONC) in r, and i filters revealed three well-separated pre-main sequences in the color-magnitude diagram (CMD). The objects belonging to the individual sequences are concentrated toward the center of the ONC. The authors concluded that there are two competitive scenarios: a population of unresolved binaries and triples with an exotic mass ratio distribution, or three stellar populations with different ages (~=1Myr age differences). We use Gaia DR2 in combination with the photometric OmegaCAM catalog to test and confirm the presence of the putative three stellar populations. We also study multiple stellar systems in the ONC for the first time using Gaia DR2. We selected ONC members based on parallaxes and proper motions and take advantage from OmegaCAM photometry that performs better than Gaia DR2 photometry in crowded regions. We identify two clearly separated sequences with a third suggested by the data. We used Pisa stellar isochrones to estimate ages of the stellar populations with absolute magnitudes computed using Gaia parallaxes on a star by star basis. (1) We confirm that the second and third sequence members are more centrally concentrated toward the center of the ONC. In addition we find an indication that the parallax and proper motion distributions are different among the members of the stellar sequences. The age difference among stellar populations is estimated to be 1-2Myr. (2) We use Gaia proper motions and other measures to identify and remove as many unresolved multiple system candidates as possible. Nevertheless we are still able to recover two well-separated sequences with evidence for the third one, supporting the existence of the three stellar populations. (3) Due to having ONC members with negligible fore- or background contamination we were able to identify a substantial number of wide binary objects (separation between 1000 and 3000 au) and with relative proper motions of the binary components consistent with zero. This challenges previously inferred values that suggested no wide binary stars exist in the ONC. Our inferred wide-binary fraction is ~=5%. We confirm the three populations correspond to three separated episodes of star formation. Based on this result, we conclude that star formation is not happening in a single burst in this region. In addition we identify 5% of wide-binary stars in the ONC that were thought not to be present.
73. OpenNGC
ID:
ivo://org.gavo.dc/openngc/q/data
Title:
OpenNGC
Short Name:
openngc.data
Date:
27 Dec 2024 08:31:01
Publisher:
The GAVO DC team
Description:
The OpenNGC object list with the main metadata
74. OpenNGC
ID:
ivo://org.gavo.dc/openngc/q/web
Title:
OpenNGC
Short Name:
openNGC
Date:
27 Dec 2024 08:31:01
Publisher:
The GAVO DC team
Description:
OpenNGC is a database containing positions and main data of NGC (New General Catalogue) and IC (Index Catalogue) objects. It has been built by merging data from NED, HyperLEDA, SIMBAD, and several databases available at HEASARC. In this VO publication, we have changed most of the column names, mostly to make them work as ADQL column names without resorting to delimited identifiers. The mapping should be obvious.
75. ORICAT Catalog of Stars in Orion Great Nebula
ID:
ivo://CDS.VizieR/J/AZh/88/143
Title:
ORICAT Catalog of Stars in Orion Great Nebula
Short Name:
J/AZh/88/143
Date:
21 Oct 2021
Publisher:
CDS
Description:
Six Tautenburg 2-m Schmidt telescope plates have been used to derive proper motions for 12740 stars down to Blim=18.5 in the region centered at RA=83.45grad, Dec=-5.20grad of the Great Nebula in Orion. Each plate covers a 3x3 grad region of sky, with a scale of 51.4"/mm. The largest difference between the epochs is 36 years. The photographic plates were scanned using Tautenburg Observatory plate scanner. The accuracy of the scans was 0.5micron, and the scale was 1000pixels/mm. The rectangular coordinates x, y and instrumental magnitudes were then determined using a dedicated software. To convert the scanned positions to the equatorial coordinates we adopt reference stars from the ACT catalog. Mean errors of position determinations are 3-4mas. The components of the proper motions and their rms uncertainties were obtained via linear least-squares fit to individual rectangular coordinates as a function of the observing epoch with no less than three epochs for every proper motion. The mean measurement uncertainty is 3.5mas/yr in magnitude interval 15-19 and 5.0mas/yr outside this interval. The photometry has been taken from Walker (1969) for B-magnitudes, and from USNO-A2.0 for R-magnitudes. Mean errors for photometry are 0.03mag in B and 0.25mag in R. The ORICAT is supplemented with the data of Parenago (1954) (stars with numbers greater 17000), and includes 13 577 stars in total. ACKNOWLEDGMENTS. We thank E. Schilbach, N.V. Kharchenko, and R.D. Scholz for numerous discussions of the results, and J. Brunzendorf and H. Meusinger for help in organizing the work at Jena Observatory.
76. Parameters of OB stars & their bow shock nebulae
ID:
ivo://CDS.VizieR/J/AJ/158/73
Title:
Parameters of OB stars & their bow shock nebulae
Short Name:
J/AJ/158/73
Date:
21 Oct 2021
Publisher:
CDS
Description:
Second only to initial mass, the rate of wind-driven mass loss determines the final mass of a massive star and the nature of its remnant. Motivated by the need to reconcile observational values and theory, we use a recently vetted technique to analyze the mass-loss rates in a sample of OB stars that generate bow shock nebulae. We measure peculiar velocities from new Gaia parallax and proper motion data and their spectral types from new optical and infrared spectroscopy. For our sample of 70 central stars in morphologically selected bow shock nebulae, 67 are OB stars. The median peculiar velocity is 11 km/s, significantly smaller than classical "runaway star" velocities. Mass-loss rates for these O and early B stars agree with recently lowered theoretical predictions, ranging from ~10^-7^ M_{sun}_/yr for mid-O dwarfs to 10^-9^ M_{sun}_/yr for late O dwarfs - a factor of about 2.7 lower than the often-used Vink et al. (2000A&A...362..295V, 2001A&A...369..574V) formulation. Our results provide the first observational mass-loss rates for B0-B3 dwarfs and giants - 10^-9^ to 10^-8^ M_{sun}_/yr. We find evidence for an increase in the mass-loss rates below a critical effective temperature, consistent with predictions of the bistability phenomenon in the range T_eff_=19000-27000 K. The sample exhibits a correlation between modified wind momentum and luminosity, consistent in slope but lower by 0.43 dex in magnitude compared to canonical wind-luminosity relations. We identify a small subset of objects deviating most significantly from theoretical expectations as probable radiation-driven bow wave nebulae by virtue of their low stellar-to-nebular luminosity ratios. For these, the inferred mass-loss rates must be regarded as upper limits.
77. Parenago Catalog of Stars in Orion Nebula
ID:
ivo://CDS.VizieR/II/171
Title:
Parenago Catalog of Stars in Orion Nebula
Short Name:
II/171
Date:
21 Oct 2021
Publisher:
CDS
Description:
The present catalogue is a machine-readable version of the catalogue of stars in the area of the Orion nebula, published by P.P. Parenago (1954). The sky area between 5h 24m and 5h 36m in right ascension (1900.0) and between -4 and -7 degrees in declination (1900.0), containing the Orion nebula, has been investigated in that work. Ten of variable stars in original Parenago (1954) catalogue had CSV numbers (Kukarkin et al., 1951) but since that time all of them were confirmed as variables and included in GCVS (Kholopov et al., 1985a&b, 1987). We superseded CSV-numbers by GCVS-names in the machine-readable version for the following stars: ------------------------------------------------ Number in CSV-number GCVS-name the catalogue ------------------------------------------------ 1605 606 V372 ORI 1613 607 V373 ORI 1635 608 V374 ORI 1713 609 V375 ORI 1748 610 V387 ORI 1762 100569 V376 ORI 1974 617 V377 ORI 2183 625 V388 ORI 2393 630 V380 ORI 2478 634 V381 ORI ------------------------------------------------
78. Positions & proper motions of radio stars
ID:
ivo://CDS.VizieR/J/A+A/312/1031
Title:
Positions & proper motions of radio stars
Short Name:
J/A+A/312/1031
Date:
21 Oct 2021
Publisher:
CDS
Description:
The optical positions of 63 extragalactic nebulae measured in the frame defined by the annual series of Carlsberg Meridian Catalogues Nos 1-8 are compared with their VLBI radio positions in the International Celestial Reference Frame. The differences between these radio and optical positions are interpreted as showing the global distortion of the Carlsberg optical frame, which is linked to that of the FK5. North of the equator the Carlsberg optical frame is within 0.05" of the ICRF; but south of the equator it deviates by 0.07" in right ascension and 0.10" in declination. The general form of the deviations follow those of the FK5, which are revealed in a recent comparison of FK5 with a preliminary version of the Hipparcos catalogue (H30).
79. Post-AGB evolution
ID:
ivo://CDS.VizieR/J/ApJS/92/125
Title:
Post-AGB evolution
Short Name:
J/ApJS/92/125
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper, we present the results for the post-AGB phases of stellar evolutionary sequences, complete from the main-sequence phase, through the AGB phase, and on into the planetary nebula and white dwarf regimes. Mass loss has been included using an empirical formalism derived from observed mass-loss rates of planetary nebula nuclei available in the literature and from radiation-pressure-driven stellar wind theory. Models are calculated for initial masses 0.89, 0.95, 1.0, 1.5, 2.0, 2.5, 3.5, and 5.0M_{sun}_, and metallicities 0.016, 0.008, 0.004, and 0.001. These abundance and mass values were chosen to allow comparison with Galactic, and Magellanic Cloud planetary nebulae and their nuclei. The post-AGB evolutionary sequences fall into two distinct groups depending on when the planetary nebula nuclei leave the AGB: one group where helium-shell burning is dominant, and the other group where hydrogen-shell burning is dominant. Of the 27 computed sequences: 17 are hydrogen-burners, and 10 are helium-burners. In only five cases was any effort made to control the phase of departure from the AGB. Lower mass models are more likely to leave the AGB burning helium, as the preceding AGB evolution has a mass-loss rate which is greatest immediately prior to a helium-shell flash. The calculations are compared with the large observational database that has developed over recent years for the Large Magellanic Cloud. These calculations will be useful for determining the planetary nebula luminosity function, and for the study of the ultraviolet excess observed in elliptical galaxies.
80. Properties of clumps in the NAN complex
ID:
ivo://CDS.VizieR/J/AJ/147/46
Title:
Properties of clumps in the NAN complex
Short Name:
J/AJ/147/46
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present observations of a 4.25deg^2^ area toward the North American and Pelican Nebulae in the J=1-0 transitions of ^12^CO, ^13^CO, and C^18^O. Three molecules show different emission areas with their own distinct structures. These different density tracers reveal several dense clouds with a surface density of over 500M_{sun}_pc^-2^ and a mean H_2_ column density of 5.8, 3.4, and 11.9x10^21^/cm2 for ^12^CO, ^13^CO, and C^18^O, respectively. We obtain a total mass of 5.4x10^4^M_{sun}_(^12^CO), 2.0x10^4^M_{sun}_(^13^CO), and 6.1x10^3^M_{sun}_(C^18^O) in the complex. The distribution of excitation temperature shows two phases of gas: cold gas (~10K) spreads across the whole cloud; warm gas (>20K) outlines the edge of the cloud heated by the W80 HII region. The kinetic structure of the cloud indicates an expanding shell surrounding the ionized gas produced by the HII region. There are six discernible regions in the cloud: the Gulf of Mexico, Caribbean Islands and Sea, and Pelican's Beak, Hat, and Neck. The areas of ^13^CO emission range within 2-10pc^2^ with mass of (1-5)x10^3^M_{sun}_ and line width of a few km/s. The different line properties and signs of star-forming activity indicate they are in different evolutionary stages. Four filamentary structures with complicated velocity features are detected along the dark lane in LDN 935. Furthermore, a total of 611 molecular clumps within the ^13^CO tracing cloud are identified using the ClumpFind algorithm. The properties of the clumps suggest that most of the clumps are gravitationally bound and at an early stage of evolution with cold and dense molecular gas.