scholarly journals Deciphering the Kinematic Structure of the Small Magellanic Cloud through Its Red Giant Population

2021 ◽  
Vol 910 (1) ◽  
pp. 36
Author(s):  
Paul Zivick ◽  
Nitya Kallivayalil ◽  
Roeland P. van der Marel
Keyword(s):  
Magellanic Cloud ◽  
Kinematic Structure ◽  
Small Magellanic Cloud ◽  
Red Giant

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 Observational Aspects of Slow Variables in Globular Clusters

1973 ◽  
Vol 21 ◽  
pp. 131-144
Author(s):  
M. W. Feast
Keyword(s):  
Radial Velocity ◽  
Compact Group ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Mira Variables ◽  
Period Effects ◽  
Slow Variables ◽  
Red Giant

AbstractThere are up to 14 known Mira variables in seven globular clusters, though several have not yet been confirmed as radial velocity members. The periods of only 5 are known, all near 200 days. The clusters seem to form a compact group of relatively metal rich clusters. In 3 or 4 cases spectroscopy shows that the giant branches of these clusters penetrate into the M types. The Mira-containing clusters also contain red variables of shorter period and smaller amplitude which are generally also M type stars. Stars apparently evolve to the red of the giant tip as variables of increasing amplitude and period. Effects of TiO blanketing on the (B — V) colours may be anticipated in these clusters.Besides variables at the red giant tip the metal poor globular cluster ω Cen contains variables with strong TiO bands. Photometry, including recent J, H, K, L photometry by Glass shows that these stars are very cool objects. They indicate an extension of the giant branch considerably cooler than previously considered for metal poor clusters.V1, NGC 121 in the Small Magellanic Cloud has a spectrum indicative of an SRd variable. It is not yet clear whether galactic stars similar to this star exist or not.

scholarly journals The VMC survey – XXXIX. Mapping metallicity trends in the Small Magellanic Cloud using near-infrared passbands

2020 ◽  
Vol 497 (3) ◽  
pp. 3746-3760
Author(s):  
Samyaday Choudhury ◽  
Richard de Grijs ◽  
Stefano Rubele ◽  
Kenji Bekki ◽  
Maria-Rosa L Cioni ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Spatial Resolution ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Galactic Centre ◽  
Small Magellanic Cloud ◽  
The West ◽  
Tidal Interactions ◽  
Red Giant ◽  
Metallicity Distribution

ABSTRACT We have derived high-spatial-resolution metallicity maps covering ∼42 deg2 across the Small Magellanic Cloud (SMC) in an attempt to understand its metallicity distribution and gradients up to a radius of ∼4○. Using the near-infrared VISTA Survey of the Magellanic Clouds, our data cover a thrice larger area compared with previous studies. We identify red giant branch (RGB) stars in spatially distinct Y, (Y − Ks) colour–magnitude diagrams. In any of our selected subregions, the RGB slope is used as an indicator of the average metallicity, based on calibration to metallicity using spectroscopic data. The metallicity distribution across the SMC is unimodal and can be fitted by a Gaussian distribution with a peak at [Fe/H] = −0.97 dex (σ[Fe/H] = 0.05 dex). We find evidence of a shallow gradient in metallicity (−0.031 ± 0.005 dex deg−1) from the Galactic Centre to radii of 2○–2${_{.}^{\circ}}$5, followed by a flat metallicity trend from ∼3${_{.}^{\circ}}$5 to 4○. We find that the SMC’s metallicity gradient is radially asymmetric. It is flatter towards the east than to the west, hinting at mixing and/or distortion of the spatial metallicity distribution (within the inner 3○), presumably caused by tidal interactions between the Magellanic Clouds.

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 Presence of red giant population in the foreground stellar sub-structure of the Small Magellanic Cloud

2021 ◽  
Author(s):  
Dizna James ◽  
Smitha Subramanian ◽  
Abinaya O Omkumar ◽  
Adhya Mary ◽  
Kenji Bekki ◽  
...  
Keyword(s):  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Eastern Region ◽  
Main Body ◽  
Small Magellanic Cloud ◽  
Similar Distance ◽  
Red Clump ◽  
Red Giant ◽  
Astrometric Data ◽  
Recent Epoch

Abstract The eastern region of the Small Magellanic Cloud (SMC) is found to have a foreground stellar sub-structure, which is identified as a distance bimodality (∼ 12 kpc apart) in the previous studies using Red Clump (RC) stars. Interestingly, studies of Red Giant Branch (RGB) stars in the eastern SMC indicate a bimodal radial velocity (RV) distribution. In this study, we investigate the connection between these two bimodal distributions to better understand the nature and origin of the foreground stellar sub-structure in the eastern SMC. We use the Gaia EDR3 astrometric data and archival RV data of RGB stars for this study. We found a bimodal RV distribution of RGB stars (separated by ∼ 35–45 km s−1) in the eastern and south-western (SW) outer regions. The observed proper motion values of the lower and higher RV RGB components in the eastern regions are similar to those of the foreground and main-body RC stars respectively. This suggests that the two RGB populations in the eastern region are separated by a similar distance as those of the RC stars, and the RGB stars in the lower RV component are part of the foreground sub-structure. Based on the differences in the distance and RV of the two components, we estimated an approximate time of formation of this sub-structure as 307 ± 65 Myr ago. This is comparable with the values predicted by simulations for the recent epoch of tidal interaction between the Magellanic Clouds. Comparison of the observed properties of RGB stars, in the outer SW region, with N-body simulations shows that the higher RV component in the SW region is at a farther distance than the main body, indicating the presence of a stellar Counter-Bridge in the SW region of the SMC.

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.

scholarly journals An overview of the structure and kinematics of the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 15-23 ◽  
Author(s):  
B. E. Westerlund
Keyword(s):  
Star Formation ◽  
Observational Data ◽  
Spiral Structure ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Line Of Sight ◽  
Small Magellanic Cloud ◽  
Complex Velocity ◽  
The Past

A vast amount of observational data concerning the structure and kinematics of the Magellanic Clouds is now available. Many basic quantities (e.g. distances and geometry) are, however, not yet sufficiently well determined. Interactions between the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC) and our Galaxy have dominated the evolution of the Clouds, causing bursts of star formation which, together with stochastic self-propagating star formation, produced the observed structures. In the youngest generation in the LMC it is seen as an intricate pattern imitating a fragmented spiral structure. In the SMC much of the fragmentation is along the line of sight complicating the reconstruction of its history. The violent events in the past are also recognizable in complex velocity patterns which make the analysis of the kinematics of the Clouds difficult.

scholarly journals A new super-soft X-ray source in the Small Magellanic Cloud: Discovery of the first Be/white dwarf system in the SMC?

2012 ◽  
Vol 537 ◽  
pp. A76 ◽  
Author(s):  
R. Sturm ◽  
F. Haberl ◽  
W. Pietsch ◽  
M. J. Coe ◽  
S. Mereghetti ◽  
...  
Keyword(s):  
White Dwarf ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
X Ray

scholarly journals UVIT-HST-Gaia-VISTA study of KRON 3 in the Small Magellanic Cloud: A cluster with an extended red clump in UV

2021 ◽  
Author(s):  
P K Nayak ◽  
A Subramaniam ◽  
S Subramanian ◽  
S Sahu ◽  
C Mondal ◽  
...  
Keyword(s):  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Variable Mass ◽  
Intrinsic Property ◽  
Small Variation ◽  
Magellanic Cloud ◽  
Spectral Energy ◽  
Small Range ◽  
Small Magellanic Cloud ◽  
Red Clump

Abstract We have demonstrated the advantage of combining multi-wavelength observations, from the ultraviolet (UV) to near-infrared, to study Kron 3, a massive star cluster in the Small Magellanic Cloud. We have estimated the radius of the cluster Kron 3 to be 2${_{.}^{\prime}}$0 and for the first time, we report the identification of NUV-bright red clump (RC) stars and the extension of the RC in colour and magnitude in the NUV versus (NUV−optical) colour-magnitude diagram (CMD). We found that extension of the RC is an intrinsic property of the cluster and it is not due to contamination of field stars or differential reddening across the field. We studied the spectral energy distribution of the RC stars, and estimated a small range in temperature ∼5000–5500 K, luminosity ∼60–90 L⊙ and radius ∼8.0–11.0 R⊙ supporting their RC nature. The range of UV magnitudes amongst the RC stars (∼23.3 to 24.8 mag) is likely caused by the combined effects of variable mass loss, variation in initial helium abundance (Yini = 0.23 to 0.28), and a small variation in age (6.5-7.5 Gyr) and metallicity ([Fe/H] = −1.5 to −1.3). Spectroscopic follow-up observations of RC stars in Kron 3 are necessary to confirm the cause of the extended RC.

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