Deep HST Photometry of NGC 6388: Age and Horizontal Branch Luminosity

M. Catelan; P. B. Stetson; B. J. Pritzl; H. A. Smith; K. Kinemuchi; A. C. Layden; A. V. Sweigart; R. M. Rich

doi:10.1086/509720

Home/Archive/arXiv

arXiv · astro-ph/0609727

Deep HST Photometry of NGC 6388: Age and Horizontal Branch Luminosity

M. Catelan·P. B. Stetson·B. J. Pritzl·H. A. Smith·K. Kinemuchi·A. C. Layden·A. V. Sweigart·R. M. Rich

View original source ↗Read source document ↗Export metadata ↓

Abstract

Using the Hubble Space Telescope, we have obtained the first color-magnitude diagram (CMD) to reach the main-sequence turnoff of the Galactic globular cluster NGC 6388. From a comparison between the cluster CMD and 47 Tucanae's, we find that the bulk of the stars in these two clusters have nearly the same age and chemical composition. On the other hand, our results indicate that the blue horizontal branch and RR Lyrae components in NGC 6388 are intrinsically overluminous, which must be due to one or more, still undetermined, non-canonical second parameter(s) affecting a relatively minor fraction of the stars in NGC 6388.

Explore related subjects

astro-ph

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

M. Catelan, P. B. Stetson, B. J. Pritzl, H. A. Smith, K. Kinemuchi, A. C. Layden, A. V. Sweigart, R. M. Rich. 2006-09-26. Deep HST Photometry of NGC 6388: Age and Horizontal Branch Luminosity. https://doi.org/10.1086/509720

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Cosmic Conundrums with Quantum Corrections

Darh energy was discovered over 25 years ago and we do not have an explanation of it. Dark matter comprises 95% of matter in the universe and we still don't know what it is. The Webb telescope has been finding fully formed galaxies with massive black holes millions of times the mass of the sun in the early universe and we don't have any explanation. A quantum density limitation will be used to solve these and other outstanding problems.

astro-ph↗

arXiv2026

On binary pulsars and the force of gravity

The energy-momentum budget of the astrophysical systems can be studied by the exact local conservation equation derived by Landau and Lifshitz. We show that a similar equation is valid for the Einstein-Cartan gravity. We reanalyze a binary pulsar system using the Landau-Lifshitz conservation equation and show that the orbital period change rate can be completely understood as a curvature backreaction process. Taking into account the detailed theoretical and observational research of relativistic binary pulsar systems, especially the system of Hulse and Taylor, we conclude that general relativity and astrophysical observations rule out the existence of gravitational radiation. We comment upon the LIGO GW events and their alternative explanation, as well as the recent pulsar timing arrays data.

astro-ph↗

arXiv2026

Oscillation frequencies and mode lifetimes in alpha Centauri A

We analyse our recently-published velocity measurements of alpha Cen A (Butler et al. 2004). After adjusting the weights on a night-by-night basis in order to optimize the window function to minimize sidelobes, we extract 42 oscillation frequencies with l=0 to 3 and measure the large and small frequency separations. We give fitted relations to these frequencies that can be compared with theoretical models and conclude that the observed scatter about these fits is due to the finite lifetimes of the oscillation modes. We estimate the mode lifetimes to be 1-2 d, substantially shorter than in the Sun.

astro-ph↗