Every 25.34 days, the object, dubbed LRLL 54361, which is is hidden behind a dense disk and envelope of dust, unleashes a burst of light.
Similar observations have been made of two other young stellar objects, but this is the most powerful yet seen.
LRLL 54361 offers insights into the early stages of star formation when lots of gas and dust is being rapidly accreted, or pulled together, to form a new binary star, the researchers say.
Astronomers have suggested the flashes are caused by material suddenly being dumped onto the growing stars, known as protostars.
A powerful blast of radiation is unleashed each time the stars get close to each other in their orbits.
This phenomenon, called pulsed accretion, has been seen in later stages of star birth, but never in such a young system or with such intensity and regularity.
'This protostar has such large brightness variations with a precise period that it is very difficult to explain,' said James Muzerolle of the Space Telescope Science Institute in Baltimore, Maryland.
His paper was recently published in the science journal Nature.
Data from Spitzer revealed the presence of protostars. Based on statistical analysis, the two stars are estimated to be no more than a few hundred thousand years old.
The Spitzer infrared data, collected repeatedly during a period of seven years, showed unusual outbursts in the brightness of the suspected binary protostar.
Surprisingly, the outbursts recurred every 25.34 days, which is a very rare phenomenon.
Astronomers used Hubble to confirm the Spitzer observations and reveal the detailed stellar structure around LRLL 54361.
The space telescope observed two cavities above and below a dusty disk. The cavities are visible by tracing light scattered off their edges.
They likely were blown out of the surrounding natal envelope of dust and gas by an outflow launched near the central stars.
The disk and the envelope prevent the suspected binary star pair from being observed directly. By capturing multiple images over the course of one pulse event, the Hubble observations uncovered a spectacular movement of light away from the centre of the system, an optical illusion known as a light echo.
Mr Muzerolle and his team hypothesised that the pair of stars in the centre of the dust cloud move around each other in a very eccentric orbit.
As the stars approach each other, dust and gas are dragged from the inner edge of a surrounding disk.
The material ultimately crashes onto one or both stars, which triggers a flash of light that illuminates the circumstellar dust.
The system is rare because close binaries account for only a few per cent of our galaxy's stellar population. This is likely a brief, transitory phase in the birth of a star system.
The team next plans to continue monitoring LRLL 54361 using other facilities including the European Space Agency's Herschel Space Telescope.
They hope to eventually obtain more direct measurements of the binary star and its orbit.
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