- ID:
- ivo://CDS.VizieR/J/A+A/603/A37
- Title:
- 4 globular clusters RGB and AGB stars
- Short Name:
- J/A+A/603/A37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic studies have demonstrated that nearly all Galactic globular clusters (GCs) harbour multiple stellar populations with different chemical compositions. Moreover, colour-magnitude diagrams based exclusively on Stroemgrem photometry have allowed us to identify and characterise multiple populations along the RGB of a large number of clusters. In this paper we show for the first time that Stroemgren photometry is also very efficient at identifying multiple populations along the AGB, and demonstrate that the AGB of M3, M92, NGC362, NGC1851, and NGC6752 are not consistent with a single stellar population. We also provide a catalogue of RGB and AGB stars photometrically identified in these clusters for further spectroscopic follow-up studies. We combined photometry and elemental abundances from the literature for RGB and AGB stars in NGC6752 where the presence of multiple populations along the AGB has been widely debated. We find that, while the MS, SGB, and RGB host three stellar populations with different helium and light element abundances, only two populations of AGB stars are present in the cluster. These results are consistent with standard evolutionary theory.
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- ID:
- ivo://CDS.VizieR/J/AJ/107/1577
- Title:
- Halo red giants reddening
- Short Name:
- J/AJ/107/1577
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Updated uvby observations for a larger sample of metal-deficient red giants are presented and combined with a select sample of data from the literature transformed to a common system. Using the reddening maps of Burstein & Heiles [AJ, 87, 1165 (1982)], new absolute magnitudes, distances, metallicities, and reddenings are derived for each star. The metallicities are determined with a revised calibration of the m1, (b-y) diagram based upon comparison to a compilation of recent spectroscopic abundances transformed to a common system. The photometric abundances agree very well with the spectroscopic; the dispersion among the residuals for 58 giants is +/-0.16dex. The dereddened indices are used to show that for red giants with [Fe/H]<-1.5, there is a well-defined relation in the c0, (b-y)0 diagram which exhibits only a weak dependence upon metallicity. Use of the standard relations allows one to obtain reddening estimates for normal halo field giants and globular clusters in the appropriate metallicity range.
- ID:
- ivo://CDS.VizieR/J/A+A/381/941
- Title:
- HST photometry of stars in N160A
- Short Name:
- J/A+A/381/941
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using high-resolution imaging with the Hubble Space Telescope, we study the Large Magellanic Cloud 2 region N160A and uncover several striking features of this complex massive star-forming site. The two compact high excitation 2 blobs (HEBs) A1 and A2 are for the first time resolved and their stellar content and morphology is revealed. A1, being of higher excitation, is powered by a single massive star whose strong wind has created a surrounding bubble. A2 harbors several exciting stars enshrouded by large quantities of dust. The whole N160A nebula is energized by three star clusters for which we obtain photometry and study their color-magnitude diagram. The 2 region is particularly dusty, with extinction values reaching an A_V_~2.5mag in the visible, and it is separated from the molecular cloud by an outstanding ionization front. A previously detected infrared young stellar object is also accurately located with respect to the 2 region (N160A).
- ID:
- ivo://CDS.VizieR/J/A+A/361/929
- Title:
- IC 4651 uvby photometry
- Short Name:
- J/A+A/361/929
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New accurate CCD photometry in the u, v, b and y bands of the Stroemgren system filters has been obtained for 17640 stars to approximately. V=20mag in a approximately 21' x 21' field centered on the intermediate-age open cluster IC 4651. The observations was obtained with the Danish 1.5-m telescope at the European Southern Observatory, La Silla, Chile. Table 1 contains information about the Date, Night, Filter, Exposure time, Airmass, CCD rotation angle, and RA- , DE-offsets for all 89 frames. Table 2 gives cross-references between the MEI-system (this paper) and the Lindoff (1972A&AS....7..231L, IC 4651 NNN), Eggen (1971ApJ...166...87E, Cl* IC 4651 Egg NN), Anthony-Twarog & Twarog (1987AJ.....94.1222A, Cl* IC 4651 AT 1-NNN, Cl* IC 4651 AT 2-NN), and Anthony-Twarog et al. (1988AJ.....95.1453A, Cl* IC 4651 AMC I-NNN, Cl* IC 4651 AMC NNNN) identification numbers. Table 3 is the final catalogue of the new Stroemgren uvby photometry, ordered by MEI identification number. For each star, it gives the MEI number, Global CCD x- and y-coordinates, J2000 coordinates , the new y, b, v, and u magnitudes on the standard system, number of detections of the individual stars, and their mean errors.
- ID:
- ivo://CDS.VizieR/J/AJ/121/2124
- Title:
- {lambda} Ori pre-main-sequence stars photometry
- Short Name:
- J/AJ/121/2124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The {lambda} Ori star-forming region presents a snapshot of a moderate-mass giant molecular cloud 1-2Myr after cloud disruption by OB stars, with the OB stars, the low-mass stellar population, remnant molecular clouds, and the dispersed gas all still present. We have used optical photometry and multiobject spectroscopy for lithium absorption to identify 266 pre-main-sequence stars in 8deg^2^ of the region. We also present new Stroemgren photometry for the massive stars, from which we derive a distance of 450pc and a turnoff age of 6-7Myr. Using these parameters and pre-main-sequence evolutionary models, we map the star formation history of the low-mass stars. We find that low-mass star formation started throughout the region at about the same time as the birth of the massive stars, and thereafter the birth rate accelerated. Within the last 1-2Myr star formation ceased in the center of the star-forming region, near the concentration of OB stars, while it continues in dark clouds 20pc away. We suggest that a supernova 1-2Myr ago destroyed the molecular cloud core from which the OB stars formed, but it did not terminate star formation in more distant reaches of the giant molecular cloud. We find no secure evidence for triggered or sequential star formation in the outer molecular clouds. The global star formation of the {lambda} Ori region has generated the field initial mass function, but local star formation in subregions shows large deviations from the expected ratio of high- to low-mass stars.
- ID:
- ivo://CDS.VizieR/J/AJ/107/1556
- Title:
- Late B-type stars classification
- Short Name:
- J/AJ/107/1556
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the fourth and final of a series of papers on the late B to the early F type stars, we refine the MK spectral classification system for the late B type stars and consider the effect of rotation on both spectral classification and Stromgren photometry of these stars. We extend the work of Morgan by establishing self-consistent sequences of narrow and broadlined standards. We reclassify a number of Bp stars, compare these classifications with Stromgren photometry and consider the question of whether all Bp stars are main-sequence objects.
- ID:
- ivo://CDS.VizieR/II/170
- Title:
- Long-term photometry of Variables I.
- Short Name:
- II/170
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the first catalogue of photometric data in the Stroemgren system obtained during the period October 1982 - September 1986. Full description can be found in ESO report SP 8. Since our goal is not absolute (all-sky) photometry, the observations should be used for differential photometry only. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 5 of paper) ------------------------------------ System y b-y m1 c1 ------------------------------------ 1 0.0109 0.0088 0.0133 0.0136 4 0.0068 0.0057 0.0079 0.0118 5 0.0087 0.0070 0.0114 0.0114 6 0.0090 0.0078 0.0126 0.0132 7 0.0071 0.0033 0.0041 0.0065 ------------------------------------
- ID:
- ivo://CDS.VizieR/II/188
- Title:
- Long-term photometry of Variables II
- Short Name:
- II/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The second catalogue of the LTPV programme contains photometric data obtained during the period October 1986 - September 1990. Full description can be found in ESO reports SP 8 and 12. The data presented here have been upgraded since the printing of catalogue ESO SR 12; a major change is the use of a quite different standard, namely the ESO SAT (Stroemgren Automatic Telescope) instrumental system has been used as standard. The instrumental systems 6 and 8 can be obtained by applying the following color matrices (see ESO SR 12, page 4, Eq. (3)), inverted (b-y , y , m1 , c1): SYSTEM 6 1.0518 0.0000 0.0000 0.0000 0.0094 1.0000 0.0000 0.0000 -0.1238 0.0000 1.1206 0.0000 0.0426 0.0000 0.0000 1.0352 SYSTEM 8 1.0476 0.0000 0.0000 0.0000 0.0384 1.0000 0.0000 0.0000 -0.0877 0.0000 1.0487 0.0000 -0.2657 0.0000 0.0000 0.9732 It also very easy to go back to the same standard as in ESO SR 8 by applying the transformations given in Table 3 of ESO SR 12 (page 3). Note that the faint star C7060 is not identified so far. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 5 of paper) ------------------------------------ System y b-y m1 c1 ------------------------------------ 6 0.0069 0.0058 0.0122 0.0129 7 0.0064 0.0030 0.0039 0.0067 8 0.0068 0.0061 0.0110 0.0097 ------------------------------------
- ID:
- ivo://CDS.VizieR/II/200
- Title:
- Long-term photometry of Variables III
- Short Name:
- II/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the third catalogue of photometric data in the Stroemgren system obtained during the period October 1990-January 1992 in the framework of the Long-Term Photometry of Variables (LTPV) program at the European Southern Observatory. All data have been obtained with the Danish 50-cm telescope. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 4 of paper) ------------------------------ y b-y m1 c1 ------------------------------ 0.005 0.002 0.004 0.006 ------------------------------
- ID:
- ivo://CDS.VizieR/II/202
- Title:
- Long-term photometry of Variables IV
- Short Name:
- II/202
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the fourth catalogue of photometric data in the Stroemgren system obtained during the period June 18, 1992 - August 23, 1994 in the framework of the Long-Term Photometry of Variables (LTPV) program at the European Southern Observatory. Since our goal is not absolute (all-sky) photometry, the observations should be used for differential photometry only. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 3 of paper) ------------------------------ y b-y m1 c1 ------------------------------ 0.005 0.002 0.004 0.007 ------------------------------
