scholarly journals Light and colour variations of Mira variables in the Small Magellanic Cloud

2020 ◽  
Vol 500 (1) ◽  
pp. 82-100
Author(s):  
Yoshifusa Ita ◽  
John W Menzies ◽  
Patricia A Whitelock ◽  
Noriyuki Matsunaga ◽  
Masaki Takayama ◽  
...  
Keyword(s):  
Near Infrared ◽  
Colour Change ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Data Set ◽  
Mira Variables ◽  
Number Ratio ◽  
Stellar Pulsation ◽  
Phase Lags ◽  
Bolometric Correction

ABSTRACT The goal of this paper is to characterize the light variation properties of Mira variables in the Small Magellanic Cloud. We have investigated a combined optical and near-infrared multi-epoch data set of Mira variables based on our monitoring data obtained over 15 yr. Bolometric correction relations are formulated for various near-infrared colours. We find that the same bolometric correction equation holds for both the bolometricly brightest and faintest pulsation phases. Period–bolometric magnitude relations and period–colour relations were derived using time-averaged values. Phase lags between bolometric phase and optical and near-infrared phases were detected from the O-rich (the surface C/O number ratio is below unity) Mira variables, while no significant systematic lags were observed in most of the C-rich (the C/O ratio is over unity) ones. Some Miras show colour phase inversions, e.g. H–Ks at its bluest while J–H and J–Ks are at their reddest values at about the bolometricly brightest phase. Their occurrence conditions were studied but no clear direct or indirect trigger was found. A large NIR colour change unassociated with stellar pulsation was observed in Miras with long secondary periods, and its possible explanation is described.

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.

scholarly journals Morphology of the Small Magellanic Cloud using multiwavelength photometry of classical Cepheids

2019 ◽  
Vol 489 (3) ◽  
pp. 3725-3738 ◽  
Author(s):  
Sukanta Deb ◽  
Kerdaris Kurbah ◽  
Harinder P Singh ◽  
Shashi M Kanbur ◽  
Chow-Choong Ngeow ◽  
...  
Keyword(s):  
Near Infrared ◽  
Weighted Average ◽  
Major Axis ◽  
Magellanic Cloud ◽  
Triaxial Ellipsoid ◽  
Distance Modulus ◽  
Viewing Angle ◽  
Small Magellanic Cloud ◽  
Distance Measurements ◽  
Classical Cepheids

ABSTRACT This is the second of a series related to the study of geometry of the Magellanic Clouds based on multiwavelength photometry of classical Cepheids. In this paper we determine the geometrical and viewing angle parameters of the Small Magellanic Cloud (SMC) using the Leavitt law for classical Cepheids with/without a break in the law at a certain period as reported in the literature. The study utilizes photometric data for more than 3400 common classical Cepheids (Fundamental (FU) and First overtone (FO)) in optical (V, I), near-infrared (Y, J, Ks) and mid-infrared ([3.6] and [4.5] μm) photometric bands. We obtain statistical reddening and distance modulus free from the effect of reddening to each of the individual Cepheids with respect to the mean distance modulus and reddening of the SMC. The reddening maps of the SMC obtained from the analyses with/without breaks in the Leavitt law show good agreement with each other as well as with other maps available in the literature. The Cartesian coordinates of individual stars with respect to the galaxy plane are obtained using the information of equatorial coordinates (α, δ) as well as extinction-free distance measurements. Modelling the observed 3D distribution of the Cepheids as a triaxial ellipsoid, we obtain the geometrical and viewing angle parameters of the SMC. The weighted average yields the following values of parameters for the SMC: the geometrical axes ratios of 1.000 ± 0.001: 1.544 ± 0.002: 9.742 ± 0.030 and the viewing angle parameters having inclination angle i = 3${^{\circ}_{.}}$465 ± 0${^{\circ}_{.}}$030 with respect to the longest axis from the line of sight and position angle of line of nodes (major axis) θlon = 63${^{\circ}_{.}}$086 ± 0${^{\circ}_{.}}$117.

scholarly journals A near-infrared VISTA of the Small Magellanic Cloud

2018 ◽  
Vol 14 (S344) ◽  
pp. 53-56
Author(s):  
Maria-Rosa L. Cioni ◽  
Florian Niederhofer ◽  
Stefano Rubele ◽  
Ning-Chen Sun
Keyword(s):  
Near Infrared ◽  
Stellar Populations ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Level Of Detail ◽  
Star Formation History ◽  
Main Body ◽  
Small Magellanic Cloud ◽  
Formation History ◽  
The Galaxy

AbstractVISTA observed the Small Magellanic Cloud (SMC), as part of the VISTA survey of the Magellanic Clouds system (VMC), for six years (2010–2016). The acquired multi-epoch YJKs images have allowed us to probe the stellar populations to an exceptional level of detail across an unprecedented wide area in the near-infrared. This contribution highlights the most recent VMC results obtained on the SMC focusing, in particular, on the clustering of young stellar populations, on the proper motion of stars in the main body of the galaxy and on the spatial distribution of the star formation history.

scholarly journals THE ARAUCARIA PROJECT: THE DISTANCE TO THE SMALL MAGELLANIC CLOUD FROM NEAR-INFRARED PHOTOMETRY OF RR LYRAE VARIABLES

2009 ◽  
Vol 138 (6) ◽  
pp. 1661-1666 ◽  
Author(s):  
Olaf Szewczyk ◽  
Grzegorz Pietrzyński ◽  
Wolfgang Gieren ◽  
Anna Ciechanowska ◽  
Fabio Bresolin ◽  
...  
Keyword(s):  
Near Infrared ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Infrared Photometry ◽  
Rr Lyrae

scholarly journals Red supergiants in the Small Magellanic Cloud: The effects of metallicity on narrow-band classification indices

2004 ◽  
Vol 193 ◽  
pp. 317-321
Author(s):  
Robert F. Wing ◽  
Kyle M. Walker ◽  
D. Jack MacConnell ◽  
Edgardo Costa
Keyword(s):  
Near Infrared ◽  
Narrow Band ◽  
Variable Stars ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Color System ◽  
The Galaxy ◽  
Red Supergiants

AbstractNarrow-band classification photometry, on a six-color system that measures near-infrared bands of TiO and CN, has been obtained for a set of red supergiants in the Small Magellanic Cloud. To investigate the effects of metallicity on the band-strength indices, comparisons are made to supergiants in the LMC and the Galaxy. Two new variable stars are reported.

scholarly journals NEAR-INFRARED PHOTOMETRY OF FOUR STELLAR CLUSTERS IN THE SMALL MAGELLANIC CLOUD

2008 ◽  
Vol 690 (1) ◽  
pp. 288-294 ◽  
Author(s):  
Alessio Mucciarelli ◽  
Livia Origlia ◽  
Claudia Maraston ◽  
Francesco R. Ferraro
Keyword(s):  
Near Infrared ◽  
Magellanic Cloud ◽  
Stellar Clusters ◽  
Small Magellanic Cloud ◽  
Infrared Photometry

scholarly journals The VMC survey – XLI. Stellar proper motions within the Small Magellanic Cloud

2021 ◽  
Vol 502 (2) ◽  
pp. 2859-2878
Author(s):  
Florian Niederhofer ◽  
Maria-Rosa L Cioni ◽  
Stefano Rubele ◽  
Thomas Schmidt ◽  
Jonathan D Diaz ◽  
...  
Keyword(s):  
Near Infrared ◽  
Magellanic Cloud ◽  
Mass Motion ◽  
Small Magellanic Cloud ◽  
Proper Motions ◽  
Spatially Resolved ◽  
Infrared Telescope ◽  
The North ◽  
The Galaxy ◽  
Older Populations

ABSTRACT We used data from the near-infrared Visible and Infrared Telescope for Astronomy (VISTA) survey of the Magellanic Cloud system (VMC) to measure proper motions (PMs) of stars within the Small Magellanic Cloud (SMC). The data analysed in this study comprise 26 VMC tiles, covering a total contiguous area on the sky of ∼40 deg2. Using multi-epoch observations in the Ks band over time baselines between 13 and 38 months, we calculated absolute PMs with respect to ∼130 000 background galaxies. We selected a sample of ∼2160 000 likely SMC member stars to model the centre-of-mass motion of the galaxy. The results found for three different choices of the SMC centre are in good agreement with recent space-based measurements. Using the systemic motion of the SMC, we constructed spatially resolved residual PM maps and analysed for the first time the internal kinematics of the intermediate-age/old and young stellar populations separately. We found outward motions that point either towards a stretching of the galaxy or stripping of its outer regions. Stellar motions towards the North might be related to the ‘Counter Bridge’ behind the SMC. The young populations show larger PMs in the region of the SMC Wing, towards the young Magellanic Bridge. In the older populations, we further detected a coordinated motion of stars away from the SMC in the direction of the Old Bridge as well as a stream towards the SMC.

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 A near infrared variable star survey in the Magellanic Clouds: The Small Magellanic Cloud data

2018 ◽  
Author(s):  
Yoshifusa Ita ◽  
Noriyuki Matsunaga ◽  
Toshihiko Tanabé ◽  
Yoshikazu Nakada ◽  
Daisuke Kato ◽  
...  
Keyword(s):  
Near Infrared ◽  
Variable Star ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Small Magellanic Cloud ◽  
Cloud Data

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.

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