scholarly journals ACTINIUM ABUNDANCES IN STELLAR ATMOSPHERES

2021 ◽  
Vol 34 ◽  
pp. 70-73
Author(s):  
V. Yushchenko ◽  
V. Gopka ◽  
A.V. Yushchenko ◽  
A. Shavrina ◽  
Ya. Pavlenkо ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Milky Way ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Stellar Atmospheres ◽  
The Other ◽  
Small Magellanic Cloud ◽  
Red Supergiants ◽  
Red Giant

This paper presents a study of radioactive  actinium in the atmospheres of stars located in galaxies with different chemical evolution history – namely, Przybylski's Star (HD 101065) in the Milky Way and the red supergiant PMMR27 in the Small Magellanic Cloud; it also reports the findings of the previous research of the red supergiant RM 1-667 in the Large Magellanic Cloud and the red giant BL138 in the Fornax dwarf spheroidal galaxy. The actinium abundance is close to that of uranium in the atmospheres of certain stars in the Milky Way’s halo and in the atmosphere of Arcturus. The following actinium abundances have been obtained (in a scale of lg N(H) = 12): for the red supergiants PMMR27 and RM 1- 667 lg N(Ac) = -1.7 and lg N(Ac) = -1.3, respectively, and for the red giant BL138 lg N(Ac) = -1.6. The actinium abundance in the atmosphere of Przybylski's Star (HD 101065) is lg N(Ac) = `0.94±0.09, which is more than two orders of magnitude higher than those in the atmospheres of the other studied stars.

scholarly journals The interstellar medium of the Magellanic Clouds from absorption lines

1991 ◽  
Vol 148 ◽  
pp. 401-406 ◽  
Author(s):  
Klaas S. De Boer
Keyword(s):  
Interstellar Medium ◽  
Absorption Line ◽  
Milky Way ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Absorption Lines ◽  
Small Magellanic Cloud ◽  
General Aspects

General aspects of ISM studies using absorption line studies are given and available data are reviewed. Topics are: galactic foreground gas, individual fields in the Magellanic Clouds (MCs) and MC coronae. Overall investigations are discussed. It is demonstrated that the metals in the gas of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) are a factor of 3 and 10, respectively, in abundance below solar levels. The depletion pattern in the LMC is similar to that of the Milky Way.

The MAGIC project – II. Discovery of two new Galactic lithium-rich Cepheids

2019 ◽  
Vol 488 (3) ◽  
pp. 3211-3221
Author(s):  
V Kovtyukh ◽  
B Lemasle ◽  
A Kniazev ◽  
L Berdnikov ◽  
G Bono ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Mixed Mode ◽  
Milky Way ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Large Telescope ◽  
Instability Strip ◽  
Red Giant ◽  
First Time

Abstract We report the discovery of two new lithium-rich Cepheids in the Milky Way (A(Li) ≈ 2.9 dex) among the targets of the MAGIC spectroscopic survey with the Southern African Large Telescope spectrographs. The 6707 Å Li feature is usually not detectable in the atmosphere of Cepheids. Only three Cepheids (two in the Milky Way and one in the Large Magellanic Cloud) had been reported so far with high lithium abundances. We examine the possibility that the Li-rich Cepheids are evolving towards the red giant branch, crossing the instability strip for the first time, as well as other possible scenarios. The two stars are mixed-mode Cepheids pulsating simultaneously in the first and in the second overtone modes. We briefly discuss the possible connection between their unusual chemical composition and their pulsational properties.

scholarly journals Characterising the Protostellar Population of the Magellanic Clouds with VLT/SINFONI

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Jacob Ward ◽  
Joana Oliveira ◽  
Jacco van Loon ◽  
Marta Sewilo
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Emission Lines ◽  
Young Stellar Objects ◽  
Small Magellanic Cloud ◽  
Stellar Objects ◽  
Accretion Rates

AbstractAt distances of ~50 kpc and ~60 kpc for the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) respectively the Magellanic Clouds present us with a unique opportunity to study star formation in environments outside our own galaxy. Through Spitzer and Herschel photometry and spectroscopy, samples of Young Stellar Objects (YSOs) have been selected and spectroscpically confirmed in the Magellanic Clouds. Here we present some of the key results of our SINFONI K-band observations towards massive YSOs in the Magellanic Clouds. We resolve a number of Spitzer sources into multiple, previously unresolved, components and our analysis of emission lines suggest higher accretion rates and different disc properties compared with massive YSOs in the Milky Way.

New Proper Motions of the Small Magellanic Cloud Using HST and Implications for Milky Way Mass

2017 ◽  
Vol 13 (S334) ◽  
pp. 394-395
Author(s):  
P. Zivick ◽  
N. Kallivayalil ◽  
S. Linden ◽  
T. Fritz ◽  
G. Besla ◽  
...  
Keyword(s):  
Milky Way ◽  
Hubble Space Telescope ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Wide Field ◽  
Small Magellanic Cloud ◽  
Proper Motions ◽  
Exact Mass ◽  
History Of ◽  
Magellanic Stream

AbstractAs new work on the proper motions (PMs) of the Large Magellanic Cloud (LMC) has come out, our view of the history of the Magellanic Clouds has evolved. We now believe they are on their first infall into the Milky Way (MW), having been tidally bound at the start of infall (though not necessarily now). Combining these observations with initial PMs of the Small Magellanic Cloud (SMC) suggests a new formation mechanism of the Magellanic Stream through the stripping of material from the SMC. However, large uncertainties remain in the exact mass of the LMC. We present a measurement of the systemic proper motions of the SMC from astrometry with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST), covering a ~3 year baseline of 30 fields with background QSOs. We find these motions to be μW = −0.82 ± 0.06 mas/yr and μN = −1.23 ± 0.07 mas/yr. Combining these measurements with previous efforts in studying the Clouds will help constrain their interactions with each other and the MW, including the mass of the LMC and the MW, as well as provide new insight into the internal dynamics of the SMC.

scholarly journals The Mid-IR Extinction Law in the LMC

2012 ◽  
Vol 8 (S292) ◽  
pp. 286-286
Author(s):  
Jian Gao ◽  
Mengyao Xue ◽  
B. W. Jiang
Keyword(s):  
Molecular Clouds ◽  
Milky Way ◽  
Interstellar Extinction ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
The Other ◽  
Additional Absorption ◽  
Mid Infrared ◽  
Grain Model

AbstractThe mid-infrared (MIR) extinction law in the Large Magellanic Cloud (LMC) at four IRAC bands is derived using the data of the Spitzer/SAGE Program. The derived mean extinctions are A[3.6]/AKs = 0.68±0.03, A[4.5]/AKs = 0.97±0.03, A[5.8]/AKs = 0.54±0.04, and A[8.0]/AKs = 0.58±0.07. The results show that: (1) The extinctions at [3.6], [5.8] and [8.0] of the LMC consist a flat curve, similar to that of the Milky Way (MW) predicted by the interstellar grain model at Rv = 5.5; (2) The extinction at [4.5] is clearly higher than the other three bands, which may be caused by the additional absorption of the 4.27μm CO2 ice and/or the 4.67μm CO ice in the LMC molecular clouds; (3) As far as individual sightlines are concerned, the MIR interstellar extinction law Aλ/AKs in the LMC varies with sightlines as the MW does.

scholarly journals Search for binary central stars of the Magellanic Clouds PNe

2016 ◽  
Vol 12 (S323) ◽  
pp. 384-385
Author(s):  
Marcin Gładkowski ◽  
Marcin Hajduk ◽  
Igor Soszyński
Keyword(s):  
Milky Way ◽  
Central Star ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Small Magellanic Cloud ◽  
Photometric Analysis ◽  
Gravitational Experiment ◽  
The Galaxy ◽  
Central Stars

AbstractThe Optical Gravitational Experiment (OGLE) was effectively used in discovering binary central stars of planetary nebulae (CSPNe). About 50 binary CSPNe have been hitherto identified in the Galaxy, almost half of them were detected in the OGLE database. We used the OGLE data to search for binary CSPNe in the Magellanic Clouds. We also searched for PNe mimics and removed them from the PNe sample. Here, we present results of the photometric analysis for Small Magellanic Cloud (SMC) and our progress on search of binary central stars in the Large Magellanic Cloud (LMC). So far, we have discovered one binary central star of the PN beyond the Milky Way, which is located in the Small Magellanic Cloud.

scholarly journals Charting cool carbon stars in the Large Magellanic Cloud

1991 ◽  
Vol 148 ◽  
pp. 353-354
Author(s):  
S.J. M.F. McCarthy ◽  
V. M. Blanco
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Carbon Stars ◽  
Red Giant ◽  
M Stars

We describe the preparation of charts and positions for 1035 cool red giant carbon stars discovered by the authors in the Large Magellanic Cloud (LMC). Not considered here are Small Magellanic Cloud (SMC) carbon stars, nor the M-type giants found in the LMC and SMC (Blanco et al. 1980, Blanco & McCarthy 1983). Charts of the C stars discovered are available in three formats: (a) 12 charts contain 186 C stars discovered in three central LMC regions (Blanco et al. 1980); (b) charts of C and late M stars in 52 LMC regions; these charts will not be published but are available from the authors (Blanco & McCarthy 1983, discussion); and (c) charts for 849 individual C stars in 49 regions of LMC (Blanco & McCarthy 1990).

scholarly journals Infrared imaging of intermediate age LMC/SMC clusters

1991 ◽  
Vol 148 ◽  
pp. 228-229
Author(s):  
H. Zinnecker ◽  
F. Ferraro ◽  
F. Fusi Pecci ◽  
Alvio Renzini ◽  
R. Buonanno ◽  
...  
Keyword(s):  
Software Package ◽  
Infrared Imaging ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Asymptotic Giant Branch ◽  
Small Magellanic Cloud ◽  
Discontinuous Change ◽  
Red Giant ◽  
Array Camera ◽  
Infrared Array

Infrared colour-magnitude diagrams (K vs. J-K) have been obtained for eight intermediate age (˜0.1-1 Gyr) Large Magellanic Cloud (LMC) clusters and one Small Magellanic Cloud (SMC) cluster (NGC 419). The data have been obtained from infrared array camera images taken at the CTIO 1.5m telescope and reduced using the software package ROMAFOT. We believe that we have observed the onset of the extended red giant branch, i.e. the discontinuous change in the infrared colour and in the number of infrared bright stars per unit optical cluster luminosity. The most luminous stars (K = 10-12.5) must be on the asymptotic giant branch; some of them are very red (J - K > 1.5) and must be carbon stars.

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