August 27, 1991

CERTAIN aging stars of the cosmic kind have made a discovery that would be the envy of Hollywood. They have hit upon a veritable fountain of youth and manage to shine with a radiance belying their years. For almost four decades, these stars have enchanted their most devoted fans, astronomers, by appearing hotter and brighter than they should be, considering some are not a day under 15 billion years old. In the usual cycle of stars, they should have cooled off long ago and, like their neighboring contemporaries, settled into a quiescent old age as red giants. Yet they masquerade as hot young blue stars much less than half their actual age.

To some it is "euphoria"; to others it is "the little rush of late." And it may not last. But Argentines and international bankers here are hoping that an economic turnaround has arrived after more than two years of recession, repeated bouts of hyperinflation and isolation from the world financial community. At the beginning of this month, the average daily trading volume on the Buenos Aires Stock Exchange was a paltry $5 million. On Friday it soared to $115 million, and the value of stocks has doubled in the same period.

Yugoslav Fighting Worsens Yugoslav Army and Serbian rebel forces pounded towns in the secessionist republic of Croatia for hours in the heaviest fighting yet. page A3.

To his best friend, Shirley MacLaine, he is an accomplished and caring composite of Don Quixote, Peter Pan, the Lone Ranger, Charlie Brown, Bart Simpson, E. T. and all of the seven dwarfs except for one: Bashful. To a political foe, Dennis Rivera, the labor leader, he is simply a "farce." Andrew Stein chooses one word to describe himself: politician. "That's what I do professionally," Mr. Stein said. "I never did anything else." Courting the Parties Nearly a quarter-century after he brashly plunged into politics as a candidate for the State Assembly, the 46-year-old New York City Council President is emerging as the leading Democratic challenger to Mayor David N. Dinkins. Mr. Stein is so much the politician that he is also the prime contender for the Liberal Party's endorsement. He is courting the Republican and Conservative parties, too. Last month, a poll showed him beating Mr. Dinkins.

A disciplinary committee at St. John's University recommended yesterday that three students who were accused of sexually assaulting a female student be expelled, even though they were acquitted of criminal charges in the case. The committee, made up of faculty members and students, also recommended the expulsion of another student who said he had joined in abusing the woman but who was not prosecuted in return for testifying against the other three.