Dr. Payne-Gaposchkin Writes of Development of Star Nova Herculia From Thirteenth Magnitude

Famous Woman Astronomer Tells of Expansion, Explosion of New 'Evening Star'

A new star shines in the sky, near to Vega, the chief component of the Lyre. It is easily seen just after sunset, sinking in the west; but it shares with the Big and Little Dippers the peculiarity of never setting in latitudes north of plus 45 degrees.

From pictures made at the Harvard Observatory, it seems that the star first began to swell at or soon after November 1. At first the swelling was probably slow, but by the middle of December the star was blowing up at the rate of more than a hundred miles a second in all directions like an inflating balloon.

Most new stars have risen to "maximum brightness" with violent speed within a day or two of discovery, but Nova Herculis, first seen as a third magnitude star on December 14, grew steadily and slowly brighter for nine more days, finally reaching the first magnitude.

On December 23 the bubble burst. That description is almost literally true; the swelling surface which had given more and more light as it expanded, became too tenuous to give constant radiation, and the effect of the large surface disappeared. The hotter radiation from the deeper layers of the star began to pour through the still expanding fragments of the bubble, and a real explosion might be said to have occurred.

The star fell very suddenly in brightness-by more than a magnitude in a day, it seems, or about three times faster than it had risen.


It was watched with interest, for so sharp a drop in brightness is uncommon, and there were many who noted that twelve hours later it had grown brighter again. In the intervening week it has apparently been fluctuating violently but regularly in brightness, about once in three days. It is not unusual for a Nova to do this, although the change is not always so rapid.

What is to happen next? By analogy with other novae, we can make a rough prediction. The star will fade slowly away, at first flickering as it fades, but at last the star will become steadily dim. Most novae have returned at last to their original brightness, so we may expect this one to sink once more to the fourteenth magnitude from which it rose. But the fall in brightness, if we may judge from present progress, will take several years, perhaps as many as ten.