* Astronomy

NGC 288 is a magnitude 8.1 globular star cluster 27000 light years away in Sculptor.
It is located located right next to (separation 1.8°) the edge on Galaxy NGC 253 which is approximately 10 million light years away.


Position(2000): RA = 00 52 47, Dec. = -26 35 24
True colour HST ACS image (202×202 arcsec) of NGC 288 core. This was constructed by combining all the r625 (red), 0.5(B435 + r625) (green), and B435 (blue) images.

Based on its structure and orbit, NGC 288 has previously been identified to be among those clusters with higher mass loss rates, and has been identified with an "extra tidal tail" that would seem to support a significant evaporation/tidal stripping rate.

Title: Chandra and Hubble Space Telescope Study of the Globular Cluster NGC 288
Authors: A.K.H. Kong, C. Bassa, D. Pooley, W.H.G. Lewin, L. Homer, F. Verbunt, S.F. Anderson, B. Margon

Astronomers report on the Chandra X-ray Observatory observations of the globular cluster NGC 288. They have detected four X-ray sources within the core radius and seven additional sources within the half-mass radius down to a limiting luminosity of LX = 7 1030 ergs s-1 (assuming cluster membership) in the 0.3-7 keV band.
They also observed the cluster with the Hubble Space Telescope Advanced Camera for Surveys and identify optical counterparts to seven X-ray sources out of the nine sources within the HST field-of-view. Based on the X-ray and optical properties, they find 2-5 candidates of cataclysmic variables (CVs) or chromospherically active binaries, and 2-5 background galaxies inside the half-mass radius. Since the core density of NGC 288 is very low, the faint X-ray sources of NGC 288 found in the Chandra and HST observations is higher than the prediction on the basis of the collision frequency.
They suggest that the CVs and chromospherically active binaries are primordial in origin, in agreement with theoretical expectation.

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Chandra ACIS-S3 0.3–7 keV image of NGC 288. The image was adaptively smoothed with CIAO tool, csmooth. The large circle represents the half-mass radius and the inner circle is the core radius. The cluster centre is marked by a cross. The square is the field-of-view of the HST/ACS. The detected X-ray sources are marked and numbered.

-- Edited by Blobrana at 20:55, 2006-03-16