(photo credit: Reuters )
A new exploding star – supernova – was first observed in the night sky between
May 31 and June 1 by amateur astronomers in France, and soon after it was
detected by the PTF Sky Survey in which Weizmann Institute scientists
participate. The phenomenon was also photographed in the new Martin Kraar
Observatory at the Rehovot-based institute, as well as in Tel Aviv University’s
Wise Observatory in Mitzpe Ramon.
Weizmann’s Dr. Avishai Gal- Yam invited
amateur astronomers who may have viewed the event to send him their time-dated
photos. They should can be sent to firstname.lastname@example.org.
with amateurs is very important to us and, in this case, it might help us
pinpoint the exact time of the explosion,” he said.
Exploding stars are
the “factories” that produce all the heavy elements found, among other places,
in our bodies. In this sense, say the researchers, we are all
Supernovae are highly energetic events that can occasionally
light up the night sky. Such an explosion generally involves disruption in the
balance between gravity, which pulls the star’s material inward, and the
thermonuclear reaction at the star’s core, which heats it and pushes it
Certain types of stars to which this occurs have a much bigger
mass – 10 to 100 times – and are much younger than our Sun. In them, the nuclear
reaction begins like that of ours, fusing hydrogen into helium – but the fusion
then continues, producing heavier and heavier elements.
reaction eventually stops with iron, as there is no energy benefit to the star
to fuse the heavier atoms, and the balance between gravity and thermonuclear
activity comes to a halt. Gravity then takes over, and the mass of the star
collapses quickly, releasing so much energy in the process that the explosion
ensues. The star hurls its outer layers into space, and a new “bright star”
appears in the night sky where none was seen before.
The newly observed
supernovae appeared in a spiral arm of our galaxy’s close neighbor, M51.
Israel’s location on the globe enables its scientists to follow supernova events
when it is daytime for many other observers, and thus to add significantly to
the data collection.
The new supernova is being studied by an
international team of researchers, including Gal-Yam and his research team of
Drs. Ofer Yaron, David Polishook and Dong Xu; research students Iair Arcavi and
Sagi Ben-Ami; Kraar Observatory director Ilan Manulis; all of the Weizmann
Institute’s Particle Physics and Astrophysics Department; as well as scientists
from the US, England, Canada and other countries.
They have already noted
that the material thrown into space in the explosion contains a wide variety of
The mix they observed is atypical of supernova events at such
an early stage of the explosion, and they plan to investigate this
The last supernova observed in M51 (which is a mere 26
million light years away) occurred in 2005. Previously, supernovae were thought
to appear about once in 100 years in any given galaxy; the frequent occurrence
in M51 can be explained by its interaction with a nearby galaxy, which causes
the process of massive star formation to accelerate, thus increasing the rate of
collapse and explosion, as well.