scholarly journals The Tip of the Red Giant Branch Distance to the Large Magellanic Cloud

2000 ◽  
Vol 119 (3) ◽  
pp. 1197-1204 ◽  
Author(s):  
Shoko Sakai ◽  
Dennis Zaritsky ◽  
Robert C. Kennicutt, Jr.
2008 ◽  
Vol 4 (S256) ◽  
pp. 9-13
Author(s):  
Yoshifusa Ita ◽  
Takashi Onaka ◽  
Daisuke Kato ◽  

AbstractWe observed an area of 10 deg2 of the Large Magellanic Cloud using the Infrared Camera on board AKARI. The observations were carried out using five imaging filters (3, 7, 11, 15, and 24 μm) and a dispersion prism (2 − 5 μm, λ/Δλ ~ 20) equipped in the IRC. The 11 and 15 μm data, which are unique to AKARI IRC, allow us to construct color-magnitude diagrams that are useful to identify stars with circumstellar dust. We found a new sequence in the color-magnitude diagram, which is attributed to red giants with luminosity fainter than that of the tip of the first red giant branch. We suggest that this sequence is likely to be related to the broad emission feature of aluminium oxide at 11.5 μm.


2021 ◽  
Vol 34 ◽  
pp. 70-73
Author(s):  
V. Yushchenko ◽  
V. Gopka ◽  
A.V. Yushchenko ◽  
A. Shavrina ◽  
Ya. Pavlenkо ◽  
...  

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.


2019 ◽  
Vol 488 (3) ◽  
pp. 3211-3221
Author(s):  
V Kovtyukh ◽  
B Lemasle ◽  
A Kniazev ◽  
L Berdnikov ◽  
G Bono ◽  
...  

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.


2020 ◽  
Vol 493 (4) ◽  
pp. 6060-6070 ◽  
Author(s):  
S Saracino ◽  
S Martocchia ◽  
N Bastian ◽  
V Kozhurina-Platais ◽  
W Chantereau ◽  
...  

ABSTRACT Recent studies have revealed that the multiple populations (MPs) phenomenon does not occur only in ancient and massive Galactic globular clusters (GCs), but it is also observed in external galaxies, where GCs sample a wide age range with respect to the Milky Way. However, for a long time, it was unclear whether we were looking at the same phenomenon in different environments or not. The first evidence that the MPs phenomenon is the same regardless of cluster age and host galaxy came out recently, when an intermediate-age cluster from the Small Magellanic Cloud, Lindsay 1, and a Galactic GC have been directly compared. By complementing those data with new images from the Hubble Space Telescope (HST), we extend the comparison to two clusters of different ages: NGC 2121 (∼2.5 Gyr) and NGC 1783 (∼1.5 Gyr), from the Large Magellanic Cloud. We find a clear correlation between the RGB (red giant branch) width in the pseudo-colour CF275W, F343N, F438W and the age of the cluster itself, with the older cluster having larger σ(CF275W, F343N, F438W)RGB and vice versa. Unfortunately, the σ values cannot be directly linked to the N-abundance variations within the clusters before properly taking account the effect of the first dredge-up. Such HST data also allow us to explore whether multiple star formation episodes occurred within NGC 2121. The two populations are indistinguishable, with an age difference of only 6 ± 12 Myr and an initial helium spread of 0.02 or lower. This confirms our previous results, putting serious constraints on any model proposed to explain the origin of the chemical anomalies in GCs.


2008 ◽  
Vol 4 (S256) ◽  
pp. 51-56 ◽  
Author(s):  
Steven R. Majewski ◽  
David L. Nidever ◽  
Ricardo R. Muñoz ◽  
Richard J. Patterson ◽  
William E. Kunkel ◽  
...  

AbstractWe describe an ongoing, large-scale, photometric and spectroscopic survey of the Large Magellanic Cloud (LMC) periphery. This survey uses WashingtonM,T2+DDO51 photometry to identify distant LMC red giant branch (RGB) star candidates; multi-object spectroscopy is used to confirm the stellar surface gravities of these RGB stars and their association with the LMC (e.g., through radial velocities). The survey now encompasses hundreds of fields ranging from the LMC center with full azimuthal coverage around the LMC and out to 23° from the LMC center. We have confirmed the existence of RGB stars with (the unusual) Magellanic velocities out to the radial limit of this survey coverage. From data in a subsample of these fields, we show that this extended population of stars makes up a diffuse structure enveloping the LMC with a two-dimensional distribution resembling a classical halo with a shallow de Vaucouleurs profile and a broad metallicity spread around a typical mean value of [Fe/H] ~ −1.0.


2009 ◽  
Vol 5 (S266) ◽  
pp. 446-446
Author(s):  
Arūnas Kučinskas ◽  
Vidas Dobrovolskas ◽  
Algimantas Černiauskas ◽  
Roma Lazauskaitė ◽  
Toshihiko Tanabé

AbstractWe derive photometric metallicities for 56 intermediate-age and old star clusters in the Large Magellanic Cloud from the slopes of their red-giant branches in near-infrared color–magnitude diagrams (CMDs). The cluster sample covers the LMC bar and disk to a distance of ~2 kpc from the LMC center. The derived cluster metallicity distribution spans a range of [Fe/H] = +0.0 . . . 1.4 and is similar to the metallicity distribution of field stars. We find that the average cluster metallicities in certain fields of the LMC bar and disk may be different, but there seems to be no compelling evidence for a global cluster metallicity gradient in the LMC.


2008 ◽  
Vol 136 (1) ◽  
pp. 375-388 ◽  
Author(s):  
Alessio Mucciarelli ◽  
Eugenio Carretta ◽  
Livia Origlia ◽  
Francesco R. Ferraro

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