A super­nova dis­cov­ered Wednes­day is closer to Earth –– approx­i­mately 21 mil­lion light years away –– than any other of its kind in a gen­er­a­tion. Astronomers believe they caught the super­nova within hours of its explo­sion using a tele­scope at the NRS’s Sedg­wick Reserve near Santa Bar­bara. Iden­ti­fy­ing a super­nova explo­sion imme­di­ately after the event is rare.

The dis­cov­ery of a super­nova so early in its life, and so close to Earth has ener­gized the astro­nom­i­cal com­mu­nity. Sci­en­tists around the world are scram­bling to observe it with as many tele­scopes as pos­si­ble, includ­ing the Hub­ble Space Tele­scope, and tele­scopes from the UC Santa Barbara-affiliated Las Cum­bres Obser­va­tory Global Tele­scope Net­work (LCOGT).

Andy How­ell, adjunct pro­fes­sor of physics at UCSB and staff sci­en­tist at LCOGT, is one of the lead­ers of the team that dis­cov­ered the super­nova. How­ell said: “We caught this super­nova ear­lier than we’ve ever dis­cov­ered a super­nova of this type. On Tues­day, it wasn’t there. Then, on Wednes­day, boom! There it was –– caught within hours of the explo­sion. As soon as I saw the dis­cov­ery image I knew we were onto some­thing big.”

The super­nova, dubbed PTF 11kly, occurred in the Pin­wheel Galaxy, located in the “Big Dip­per,” also known as Ursa Major. It was dis­cov­ered by the Palo­mar Tran­sient Fac­tory (PTF) sur­vey, which is designed to observe and uncover astro­nom­i­cal events as they happen.

Such super­novae reach the bright­ness of more than a bil­lion suns in the first three weeks after the explo­sion, because the process cre­ates ener­getic radioac­tive ele­ments that decay and emit light, accord­ing to How­ell. They nor­mally can’t be seen so soon after the explo­sion because they are too faint. The rel­a­tive close­ness of this event was one fac­tor that led to the unprece­dented early obser­va­tions. The other fac­tor is the use of robotic tele­scopes. The PTF sur­vey uses auto­mated tele­scopes to scan the sky nightly and alert observers when some­thing has changed. Robotic tele­scopes at LCOGT then allow imme­di­ate follow-up observations.

LCOGT is build­ing a net­work of robotic tele­scopes around the world. The first three are active in Hawaii, Aus­tralia, and at the Sedg­wick Reserve, near Santa Ynez, Calif. New images of the super­nova from Wednes­day night – taken by the Byrne Obser­va­tory Tele­scope at the Sedg­wick Reserve and another tele­scope in Hawaii – showed the super­nova had bright­ened by more than a fac­tor of 20 less than a day after discovery.

“PTF 11kly is get­ting brighter by the minute,” said Peter Nugent, the senior sci­en­tist at Berke­ley Lab who first spot­ted the super­nova. Nugent is also an adjunct pro­fes­sor of astron­omy at UC Berkeley.

“Type Ia super­novae are the kind we use to mea­sure the expan­sion of the uni­verse. See­ing one explode so close by allows us to study these events in unprece­dented detail,” said Mark Sul­li­van, the Oxford Uni­ver­sity team leader who was among the first to fol­low up on this detection.

The team put in an urgent request to acti­vate the Hub­ble Space Tele­scope on Wednes­day. The telescope’s sched­ule is set weeks in advance, but was inter­rupted to insert reg­u­lar obser­va­tions of the new super­nova start­ing Sat­ur­day. This will allow the team to probe the physics and chem­istry of the explosion.

Catch­ing super­novae so early allows a rare glimpse at the outer lay­ers of the super­nova, which con­tain hints about what kind of star exploded. “When you catch them this early, mixed in with the explo­sion you can actu­ally see unburned bits from the star that exploded: It is remark­able,” said How­ell. “We are find­ing new clues to solv­ing the mys­tery of the ori­gin of these super­novae that has per­plexed us for 70 years. Despite look­ing at thou­sands of super­novae, I’ve never seen any­thing like this before.”

He calls the stars that explode as Type Ia super­novae “zom­bie” stars because they’re dead, with a core of ash, but they come back to life by suck­ing mat­ter from a com­pan­ion star. Over the past 50 years, astro­physi­cists have dis­cov­ered that Type Ia super­novae are part of binary sys­tems –– two stars orbit­ing each other. The one that explodes is a white dwarf star. “That’s what our sun will be at the end of its life,” he said. “It will have the mass of the sun crammed into the size of the Earth.”

The rel­a­tive close­ness of this super­nova means that even ama­teur astronomers will be able to see it in the com­ing weeks. “The best time to see this explod­ing star will be just after evening twi­light in the North­ern hemi­sphere in a week or so,” said Sul­li­van. “You’ll need dark skies and a good pair of binoc­u­lars, although a small tele­scope would be even better.”

The sci­en­tists in the PTF have dis­cov­ered more than 1,000 super­novae since it started oper­at­ing in 2008, but they believe this could be their most sig­nif­i­cant dis­cov­ery. The last time a super­nova of this sort occurred so close to Earth was in 1986, but Nugent notes that it was pecu­liar and heav­ily obscured by dust.

“Before that, you’d have to go back to 1972, 1937 and 1572 to find more nearby Type Ia super­novae,” said Nugent. “Observ­ing PTF 11kly unfold should be a wild ride. It is an instant cos­mic classic.”

“Back then we didn’t have mod­ern instru­ments,” noted How­ell. “Now we have dig­i­tal cam­eras, robotic tele­scopes, and all kinds of orbit­ing satel­lites that can see in x-rays, the ultra­vi­o­let, and vis­i­ble light. We’re going to have a field day.”

from the UC Santa Bar­bara Office of Pub­lic Affairs