14 DAY TRIAL // The Star of Bethlehem is perhaps the best-known space event in all recorded history.
People have asked along the time which may have been its origins.
And many hypotheses arose.
Was that the "sign" of a comet, a nova or something supernatural?
The most common answer is the star might have been a nova: A "new star" suddenly blazing forth where no star had been watched previously.
Usually, novas are dying stars having a final fling before passing to a white dwarf, but some stars, known as recurrent novae, go through such contortions more than once.
Such a star could flash at anytime and less than 10 are currently confirmed. For instance, T Pyxidis (photo), in the constellation of Pyxis, the Mariner's Compass, a dim southern constellation.
Seen from Philadelphia, Indianapolis and Denver, it has a maximum altitude of just 18 degrees above the southern horizon
Currently, Pyxis is crossing the meridian around 2:30 a.m. but by early March, it will be just before 10 p.m.
T Pyxidis is situated at about 6,000 light years and it's composed of a dense white dwarf and a close companion star.
An explosion occurs when the temperature and density of matter thrown from the companion onto the surface of the white dwarf reach the nuclear hydrogen flash point.
While material is violently expelled in all directions, the white dwarf itself is not affected and soon begins to store more matter from its companion, and after a few years, the process repeats.
T Pyxidis's brightness is rated at magnitude 14, a thousand times dimmer than the faintest star that can be perceived by most human eyes on a dark, clear night.
But five times, in 1890, 1902, 1920, 1944 and 1967, this star shone to magnitudes between 6.5 and 7, being visible without any optical aid.
These eruptions emerge between 19 to 24 years but the last explosion took place 40 years ago, on Dec. 7, 1966, when the star glowed at magnitude 6.3 before slowly fading back to normal.
The general opinion is that T Pyxidis may have accumulated an extra-thick coating of nuclear fuel on its surface over these past 20 years, which would provoke a super explosion with an extra brightness.
Photo credit: NASA.