2012A&A...542A..79C


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.18CET08:37:29

2012A&A...542A..79C - Astronomy and Astrophysics, volume 542A, 79-79 (2012/6-1)

The ARAUCARIA project: grid-based quantitative spectroscopic study of massive blue stars in NGC 55.

CASTRO N., URBANEJA M.A., HERRERO A., GARCIA M., SIMON-DIAZ S., BRESOLIN F., PIETRZYNSKI G., KUDRITZKI R.-P. and GIEREN W.

Abstract (from CDS):

The quantitative study of the physical properties and chemical abundances of large samples of massive blue stars at different metallicities is a powerful tool to understand the nature and evolution of these objects. Their analysis beyond the Milky Way is challenging, nonetheless it is doable and the best way to investigate their behavior in different environments. Fulfilling this task in an objective way requires the implementation of automatic analysis techniques that can perform the analyses systematically, minimizing at the same time any possible bias. As part of the ARAUCARIA project we carry out the first quantitative spectroscopic analysis of a sample of 12 B-type supergiants in the galaxy NGC 55 at 1.94Mpc away. By applying the methodology developed in this work, we derive their stellar parameters, chemical abundances and provide a characterization of the present-day metallicity of their host galaxy. Based on the characteristics of the stellar atmosphere/line formation code fastwind, we designed and created a grid of models for the analysis of massive blue supergiant stars. Along with this new grid, we implemented a spectral analysis algorithm. Both tools were specially developed to perform fully consistent quantitative spectroscopic analyses of low spectral resolution of B-type supergiants in a fast and objective way. We present the main characteristics of our fastwind model grid and perform a number of tests to investigate the reliability of our methodology. The automatic tool is applied afterward to a sample of 12 B-type supergiant stars in NGC 55, deriving the stellar parameters, Si, C, N, O and Mg abundances. The results indicate that our stars are part of a young population evolving towards a red supergiant phase. For half of the sample we find a remarkable agreement between spectroscopic and evolutionary masses, whilst for the rest larger discrepancies are present, but still within the uncertainties. The derived chemical composition hints to an average metallicity similar to the one of the Large Magellanic Cloud, with no indication of a spatial trend across the galaxy. The consistency between the observed spectra and our stellar models supports the reliability of our methodology. This objective and fast approach allows us to deal with large samples in an accurate and more statistical way. These are two key issues to achieve an unbiased characterization of the stars and their host galaxies.

Abstract Copyright:

Journal keyword(s): stars: early-type - stars: fundamental parameters - galaxies: stellar content - galaxies: individual: NGC 55

Simbad objects: 31

goto Full paper

goto View the reference in ADS

Number of rows : 31

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME WLM Galaxy G 00 01 57.9 -15 27 50   11.50 11.10 10.93   ~ 556 2
2 [CHG2008] D-27 * 00 14 28.730 -39 10 17.76     19.191   19.833 B2I 3 0
3 [CHG2008] C1-9 * 00 14 45.540 -39 12 38.17     18.939   19.756 B1I 3 0
4 [CHG2008] C1-13 * 00 14 51.860 -39 10 57.35     18.948   19.654 B1I 3 0
5 NGC 55 GiG 00 14 53.602 -39 11 47.86 8.54 8.58 7.87 7.84   ~ 686 2
6 [CHG2008] C1-44 * 00 15 11.290 -39 12 34.55     19.037   19.777 B0I 3 0
7 [CHG2008] C1-45 * 00 15 11.310 -39 12 50.40     19.607   19.787 B1I 3 0
8 [CHG2008] C1-53 * 00 15 14.640 -39 13 36.12     19.816   20.301 B2.5I 3 0
9 [CHG2008] B-31 * 00 15 32.220 -39 14 40.20     19.429   19.907 B2.5I 3 0
10 [CHG2008] A-8 * 00 15 44.180 -39 14 58.20     19.792   19.980 O9.7I 3 0
11 [CHG2008] A-11 * 00 15 45.170 -39 15 56.15     18.706   18.951 B5I 3 0
12 [CHG2008] A-17 * 00 15 51.420 -39 15 57.60     20.336   20.657 B1I 3 0
13 [CHG2008] A-26 * 00 15 55.450 -39 15 30.60     19.236   19.498 B2.5I 3 0
14 [CHG2008] A-27 * 00 15 58.030 -39 14 27.60     19.928   20.405 B2I 3 0
15 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 10581 1
16 NGC 247 LSB 00 47 08.554 -20 45 37.44 10.11 9.61 9.10 8.87   ~ 358 2
17 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 2864 2
18 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9107 1
19 NGC 300 GiG 00 54 53.4460065856 -37 41 03.182962667 8.83 8.69 8.13 7.46   ~ 1271 2
20 IC 1613 GiC 01 04 54.2 +02 08 00   10.42 10.01 9.77   ~ 1081 2
21 M 33 GiG 01 33 50.904 +30 39 35.79 6.17 6.27 5.72     ~ 5026 1
22 * 10 Per s*b 02 25 16.0286810463 +56 36 35.357178267 5.95 6.56 6.26 5.93 5.74 B2Ia 228 0
23 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5387 1
24 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14346 1
25 * kap Ori s*b 05 47 45.3888404 -09 40 10.577707 0.87 1.88 2.06 2.09 2.27 B0.5Ia 545 0
26 NGC 3109 G 10 03 06.877 -26 09 34.46 11.10 10.42 10.04 9.91   ~ 681 2
27 NGC 3621 AGN 11 18 16.300 -32 48 45.36 10.10 9.44 9.56 8.07 10.1 ~ 476 3
28 NGC 6822 G 19 44 56.199 -14 47 51.29   18 8.1     ~ 1408 0
29 * 19 Cep ** 22 05 08.7884887056 +62 16 47.323982519 4.36 5.19 5.11 4.95 4.92 O9Ib 361 0
30 NGC 7793 GiG 23 57 49.7533807411 -32 35 27.708304655 10.26 9.74 9.28 9.06 9.7 ~ 892 2
31 NAME Local Group GrG ~ ~           ~ 6679 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2012A&A...542A..79C and select 'bookmark this link' or equivalent in the popup menu


2019.11.18-08:37:29

© Université de Strasbourg/CNRS

    • Contact