Shapley, Astronomy Head, Announces Identification of Gigantic Star Clusters

Two giant star clusters first found by the Blue Hills Observatory last spring have at last been identified, with great importance to astronomical research, Harlow Shapley, Paine Professor of Practical Astronomy and Director of the Blue Hills Observatory, revealed in Fort Davis, Texas, yesterday.

With the aid of Mount Wilson Observatory, California, it has been possible to show definitely that the two mammoth star islands, each containing thousands of stars, belong to an entirely new class of stellar system, hitherto unknown in the universe.

Stars Extraordinary in Shape

Professor Shapley said astronomers attach much importance to the fact that the objects form an "Intermediate" type, midway between the ordinary spheroidal galaxy and the ordinary globular cluster.

Professor Shapley spoke yesterday morning before a symposiumn of twenty leading astronomers, assembled at the dedication ceremonies of the new 82-inch reflector of the McDonald Observatory. Professor Shapley's paper dealt with the use of variable stars in studying structure and dimensions of stellar systems.

Belong to New Grouping

Astronomers suspected a year ago that the newly discovered massive objects,--one in the constellation Sculptor and the other in Fornax,--belonged to a new grouping. But proof had to awalt the discovery within the systems of variable stars, whose fluctuating light beams would enable a measurement of distance.

A number of variable stars were discovered in the systems by Walter Baade and Edmund P. Hubble using the powerful talescope of Mount Wilson Observatory. It was then found that older Harvard sky photographs taken at the South African station had recorded some of these variable stars. Determination of the distance of the new system followed.

The object in Sculptor was found to be 290,000 light years distant, and to have a diameter of 6,500 light years. The Fornax cluster is further away and a little larger, but belongs in the same class.

Give Off Faint Light

Despite their enormous size, the new systems give off a very faint light. Harvard's finding of the groups was a matter largely of good fortune, resulting from the fact that an abnormally sensitive photographic plate chanced to be focussed on the objects on very clear nights.

Probably these systems are not uncommon in the universe, but have been hidden from man through difficulty of observation, Professor Shapley said.

The now clusters are roughly globe-shaped, with a slight elongation in an east-west direction. The star population of the clusters is arranged with considerable compactness at the center, with the space between stars increasing toward the outer boundaries.