In the News
“ The amazing thing for me is, that supernova exploded 21 million years ago.... and we just happened to open up the telescope on that
Wednesday night, and in came the photons. ” — MARK SULLIVAN
Humans Iceman’s last meal
Astronomers
celebrate as
star goes boom
in neighborhood
supernova bursts into view
in nearby Pinwheel Galaxy
STORY ONE
By Nadia Drake
Many people appreciate a good light show, but prob- ably not as much as the astronomers who recently
spied a rare cosmological treat.
On August 24 at 03:59 Universal time,
telescopes at the Palomar Observatory
in southern California captured a white
dwarf star just 21 million light-years
away — the next state over, astronomically — as it went supernova, exploding
in a blaze of light. Scientists involved
in the Palomar Transient Factory sky
survey raced to record the dwarf’s early
death throes.
“We think we found it probably 12
hours after it exploded,” says astronomer
Mark Sullivan of the University of Oxford
in England. “The amazing thing for me is,
that supernova exploded 21 million years
ago. It’s taken light 21 million years to
arrive. And we just happened to open up
the telescope on that Wednesday night,
and in came the photons.”
Located in the Pinwheel Galaxy (
officially labeled M101), the new supernova
is the type that astronomers designate
as 1a. Seeing a type 1a supernova so soon
after birth and so close by is a rarity.
The Pinwheel Galaxy (technical name, M101) is one of the most picturesque in
the cosmos and now also one of the most popular among astronomers, who raced
to observe the brightening of a supernova that appeared there on August 24.
“Saying it’s ‘once in a generation’
is very true,” says astronomer Peter
Nugent of Lawrence Berkeley National
Laboratory. In the last four decades,
Nugent notes, astronomers know of
only three supernovas that have gone
off at this distance or closer — and just
one, observed in 1972, was a type 1a. Only
supernova 1987a, a peculiar type 2, or
core-collapse, supernova was detected
as soon after exploding.
“It’s like watching popcorn pop — you
don’t know which kernel will go next,”
says astrophysicist Adam Riess of Johns
Hopkins University in Baltimore.
On August 27, the Hubble Space
Telescope swiveled to stare at the new
stellar outburst, nestled near a kink in
the Big Dipper’s handle. The brightening supernova, called PTF 11kly, was
expected to reach peak luminosity during the second week of September, when
even a good pair of binoculars could
reveal the object to the casual observer
on a dark night.
Type 1a supernovas occur after a white
dwarf star gains weight, probably from
eating material shed by a companion
star. When the tiny, Earth-sized white
dwarf exceeds about 1. 4 times the mass
