The Local Distance Scale: How Reliable is it?

Author(s):  
M. W. Feast
Author(s):  
R. A. Schommer ◽  
E. W. Olszewski ◽  
M. A. Aaronson

2014 ◽  
Vol 10 (S306) ◽  
pp. 298-300
Author(s):  
Gabriel I. Perren ◽  
Ruben A. Vázquez ◽  
Andrés E. Piatti ◽  
André Moitinho

AbstractStar clusters are among the fundamental astrophysical objects used in setting the local distance scale. Despite its crucial importance, the accurate determination of the distances to the Magellanic Clouds (SMC/LMC) remains a fuzzy step in the cosmological distance ladder. The exquisite astrometry of the recently launched ESA Gaia mission is expected to deliver extremely accurate statistical parallaxes, and thus distances, to the SMC/LMC. However, an independent SMC/LMC distance determination via main sequence fitting of star clusters provides an important validation check point for the Gaia distances. This has been a valuable lesson learnt from the famous Hipparcos Pleiades distance discrepancy problem. Current observations will allow hundreds of LMC/SMC clusters to be analyzed in this light.Today, the most common approach for star cluster main sequence fitting is still by eye. The process is intrinsically subjective and affected by large uncertainties, especially when applied to poorly populated clusters. It is also, clearly, not an efficient route for addressing the analysis of hundreds, or thousands, of star clusters. These concerns, together with a new attitude towards advanced statistical techniques in astronomy and the availability of powerful computers, have led to the emergence of software packages designed for analyzing star cluster photometry. With a few rare exceptions, those packages are not publicly available.Here we present OCAAT (Open Cluster Automated Analysis Tool), a suite of publicly available open source tools that fully automatises cluster isochrone fitting. The code will be applied to a large set of hundreds of open clusters observed in the Washington system, located in the Milky Way and the Magellanic Clouds. This will allow us to generate an objective and homogeneous catalog of distances up to ~ 60 kpc along with its associated reddening, ages and metallicities and uncertainty estimates.


2007 ◽  
Vol 671 (2) ◽  
pp. 1640-1668 ◽  
Author(s):  
Deokkeun An ◽  
Donald M. Terndrup ◽  
Marc H. Pinsonneault

2017 ◽  
Vol 599 ◽  
pp. A67 ◽  
Author(s):  
Stefano Casertano ◽  
Adam G. Riess ◽  
Beatrice Bucciarelli ◽  
Mario G. Lattanzi

1997 ◽  
Vol 38 (5) ◽  
pp. 4-4 ◽  
Author(s):  
John Fernley

1984 ◽  
Vol 75 ◽  
pp. 265-277
Author(s):  
J.B. Holbelg ◽  
W.T. Forrester

ABSTRACTDuring the Voyager 1 and 2 Saturn encounters the ultraviolet spectrometers observed three separate stellar occultations by Saturn's rings. Together these three observations, which sampled the optical depth of the rings at resolutions from 3 to 6 km. can be used to establish a highly accurate distance scale allowing the identification of numerous ring features associated with resonances due to exterior satellites. Three separate observations of an eccentric ringlet near the location of the Titan apsidal resonance are discussed along with other ringlet-resonance associations occurring in the C ring. Density waves occurring in the A and B rings are reviewed and a detailed discussion of the analysis of one of these features is presented.


1987 ◽  
Author(s):  
Bruce G. Link ◽  
Francis T. Cullen ◽  
James Frank ◽  
John F. Wozniak

2020 ◽  
Author(s):  
Shubao Chen ◽  
Yuejiao Ma ◽  
Weifu Cai ◽  
Tania Moretta ◽  
Xuyi Wang ◽  
...  

1999 ◽  
Vol 521 (1) ◽  
pp. 155-178 ◽  
Author(s):  
L. M. Macri ◽  
J. P. Huchra ◽  
P. B. Stetson ◽  
N. A. Silbermann ◽  
W. L. Freedman ◽  
...  

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