- ID:
- ivo://CDS.VizieR/J/AJ/140/379
- Title:
- Stellar associations in M51
- Short Name:
- J/AJ/140/379
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using data acquired as part of a unique Hubble Heritage imaging program of broadband colors of the interacting spiral system M51/NGC5195, we have conducted a photometric study of the stellar associations across the entire disk of the galaxy in order to assess trends in size, luminosity, and local environment associated with the recent star formation (SF) activity in the system. Starting with a sample of over 900 potential associations, we have produced color-magnitude and color-color diagrams for the 120 associations that were deemed to be single-aged.
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- ID:
- ivo://CDS.VizieR/J/ApJS/251/29
- Title:
- Stellar bow shock nebulae spectroscopic obs.
- Short Name:
- J/ApJS/251/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Arcuate mid-infrared nebulae known as stellar bow shock nebulae (SBNe) have been previously hypothesized to be supported by the strong stellar winds and/or luminosity of massive early-type stars. We present an optical spectroscopic survey of 84 stars identified from mid-infrared images as candidate SBN-supporting stars. Eighty-one of 84 sources, 96%, are O or early-B spectral types. K-band luminosities for a larger sample of 289 stars at the centers of bow shock nebulae are overwhelmingly consistent with OB stars. This affirms both that SBNe are supported by massive stars and that arcuate mid-infrared nebulae are reliable indicators of the presence of a massive star. The radial velocity dispersions of these systems and detections of double-lined systems indicate that at least 27 of the 74 systems with multiple observations (>36%) are candidate multiple-star systems. This rate is consistent with observed multiplicity rates of field OB stars detected with similar radial velocity surveys and lower than, but not inconsistent with, the multiplicity rates of OB stars in clusters and associations.
- ID:
- ivo://CDS.VizieR/J/A+A/392/741
- Title:
- Stellar Catalogue in the Chandra DFS
- Short Name:
- J/A+A/392/741
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar catalogues in five passbands (UBVRI) over an area of approximately 0.3{deg}^2^, comprising about 1200 objects, and in seven passbands (UBVRIJK) over approximately 0.1{deg}^2^, comprising about 400 objects, in the direction of the Chandra Deep Field South are presented. The 90% completeness level of the number counts is reached at approximately U=23.8, B=24.0, V=23.5, R=23.0, I=21.0, J=20.5, K=19.0. These multi-band catalogues have been produced from publicly available, single passband catalogues. A scheme is presented to select point sources from these catalogues, by combining the SExtractor parameter CLASS_STAR from all available passbands. Probable QSOs and unresolved galaxies are identified by using the previously developed {chi}^2^-technique (Hatziminaoglou et al., 2002, Cat. <J/A+A/384/81>), that fits the overall spectral energy distributions to template spectra and determines the best fitting template. Approximately 15% of true galaxies are misclassified as stars by the {chi}^2^ method. The number of unresolved galaxies and QSOs identified by the {chi}^2^-technique, allows us to estimate that the remaining level of contamination by such objects is at the level of 2.4% of the number of stars. The fraction of missing stars being incorrectly removed as QSOs or unresolved galaxies is estimated to be similar. The resulting stellar catalogues and the objects identified as likely QSOs and unresolved galaxies with coordinates, observed magnitudes with errors and assigned spectral types by the {chi}^2^-technique are presented and are publicly available.
- ID:
- ivo://CDS.VizieR/II/95
- Title:
- Stellar Component of the Galaxy, AFGL IR Survey
- Short Name:
- II/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measurements at 2.3, 3.6, 4.9, 8.7, 10, 11.4, 12.6, 19, and 23 {mu}m are included in this catalog based on observations by the Wyoming Infrared Observatory. The sources included are those from the AFGL survey with the 4mu magnitude brighter than +1.3, the 11mu magnitude brighter than -1.5, or the 20mu magnitude brighter than -4, which lie between 20 and 40 minutes in each hour of right ascension.
- ID:
- ivo://CDS.VizieR/J/AJ/103/1205
- Title:
- Stellar Content of LH 9 and 10 in the LMC
- Short Name:
- J/AJ/103/1205
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD photometry and spectroscopy for stars in Lucke-Hodge 9 and 10, two adjacent OB association in the northwest corner of the LMC. Our catalog contains UBV photometry (complete to ~18mag in all three filters) for 795 stars and BV-only photometry (complete to ~19mag in both filters) for an additional 434 stars.
- ID:
- ivo://CDS.VizieR/J/AJ/98/1305
- Title:
- Stellar content of NGC 346
- Short Name:
- J/AJ/98/1305
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using CCD UBV photometry and spectroscopy, we have investigated the stellar content of NGC 346, the brightest H II region in the SMC. Spectra of 42 stars confirm that 33 are of O type, of which 11 are of type O6.5 or earlier; this is as many early-type O stars as is known in the rest of the SMC. From the spectroscopy and photometry we are able to construct an H-R diagram which is essentially complete down to ~10M_{sun}_. We find an initial mass-function slope {GAMMA}=-1.9, similar to that found for massive stars near the Sun and in the LMC: the presence of six stars in the mass range 40-85M_{sun}_ suggests that the upper-mass limit of the IMF is also not appreciably lower in the SMC than it is in the Galaxy. Our photometry has identified five probable red supergiants of which one was previously known. These stars, plus two B supergiants, are evolved stars of considerably lower mass (15M_{sun}_) than many of the unevolved cluster members. Most of these lower-mass, evolved stars form a spatially distinct subgroup; we believe that NGC 346 thus provides an example of sequential star formation in the SMC. We also have identified a background field population of 5M_{sun}_ stars. We find that the ionizing flux from the hot stars is consistent with the previously known Half nebular luminosity. Finally, we discuss the enigmatic W-R binary HD 5980, which our point-spread-function fitting has identified as a close visual double.
- ID:
- ivo://CDS.VizieR/J/AJ/105/980
- Title:
- Stellar content of Tr 14 and Tr 16
- Short Name:
- J/AJ/105/980
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The stellar content of the region around {eta} Car is investigated using CCD photometry and spectroscopy.
- ID:
- ivo://CDS.VizieR/J/ApJ/757/112
- Title:
- Stellar diameters. II. K and M-stars
- Short Name:
- J/ApJ/757/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present interferometric angular diameter measurements of 21 low-mass, K- and M-dwarfs made with the CHARA Array. This sample is enhanced by adding a collection of radius measurements published in the literature to form a total data set of 33 K-M-dwarfs with diameters measured to better than 5%. We use these data in combination with the Hipparcos parallax and new measurements of the star's bolometric flux to compute absolute luminosities, linear radii, and effective temperatures for the stars. We develop empirical relations for ~K0 to M4 main-sequence stars that link the stellar temperature, radius, and luminosity to the observed (B-V), (V-R), (V-I), (V-J), (V-H), and (V-K) broadband color index and stellar metallicity [Fe/H]. These relations are valid for metallicities ranging from [Fe/H]=-0.5 to +0.1dex and are accurate to ~2%, ~5%, and ~4% for temperature, radius, and luminosity, respectively. Our results show that it is necessary to use metallicity-dependent transformations in order to properly convert colors into stellar temperatures, radii, and luminosities.
- ID:
- ivo://CDS.VizieR/J/ApJS/166/249
- Title:
- Stellar dynamics and proper motions in 47Tuc
- Short Name:
- J/ApJS/166/249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used HST imaging of the central regions of the globular cluster 47 Tucanae (=NGC 104), taken with the WFPC2 and ACS instruments between 1995 and 2002, to derive proper motions and U- and V-band magnitudes for 14366 stars within 100 (about 5 core radii) of the cluster center. This represents the largest set of member velocities collected for any globular cluster. The stars involved range in brightness from just fainter than the horizontal branch of the cluster to more than 2.5mag below the main-sequence turnoff. In the course of obtaining these kinematic data, we also use a recent set of ACS images to define a list of astrometrically calibrated positions (and F475W magnitudes) for nearly 130000 stars in a larger, 3x3 central area. We describe our data reduction procedures in some detail and provide the full position, photometric, and velocity data.
- ID:
- ivo://CDS.VizieR/J/AJ/151/166
- Title:
- Stellar flares and variables from 2009-2010 CSTAR
- Short Name:
- J/AJ/151/166
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Chinese Small Telescope Array (CSTAR) carried out high-cadence time-series observations of ~20.1 square degrees centered on the South Celestial Pole during the 2008, 2009, and 2010 winter seasons from Dome A in Antarctica. The nearly continuous six months of dark conditions during each observing season allowed for >10^6^ images to be collected through gri and clear filters, resulting in the detection of >10^4^ sources over the course of three years of operation. The nearly space-like conditions in the Antarctic plateau are an ideal testbed for the suitability of very small-aperture (<20cm) telescopes to detect transient events, variable stars, and stellar flares. We present the results of a robust search for such objects using difference image analysis of the data obtained during the 2009 and 2010 winter seasons. While no transients were found, we detected 29 flaring events and find a normalized flaring rate of 5+/-4*10^-7^flare/hr for late-K dwarfs, 1+/-1*10^-6^flare/hr for M dwarfs and 7+/-1*10^-7^flare/hr for all other stars in our sample. We suggest future small-aperture telescopes planned for deployment at Dome A would benefit from a tracking mechanism, to help alleviate effects from ghosting, and a finer pixel scale, to increase the telescope's sensitivity to faint objects. We find that the light curves of non-transient sources have excellent photometric qualities once corrected for systematics, and are limited only by photon noise and atmospheric scintillation.