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Second Parameter Effects in and between M3 and Palomar 3

M. Catelan·R. T. Rood·F. R. Ferraro
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Abstract

We study the globular clusters M3 and Palomar 3 as a "second parameter (2ndP) pair," showing that: i) M3 has a surprisingly strong *internal* 2ndP; ii) The dispersion in mass on the Pal 3 horizontal branch (HB) is intrinsically very small, leading to the most apparent differences in HB morphology between M3 and Pal 3; iii) Ignoring the difference in HB mass dispersion between M3 and Pal 3, their relative HB types can be accounted for by a fairly small difference in age, of order 0.5-1 Gyr.

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M. Catelan, R. T. Rood, F. R. Ferraro. 2001-05-21. Second Parameter Effects in and between M3 and Palomar 3. https://arxiv.org/abs/astro-ph/0105350

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