February 23, 2017
Dr. Ángel R. López-Sánchez (AAO/MQU)
Ph: + 61 406 265 917
Amanda Bauer (AAO)
Ph: +61 293 724 852 / +61 447 029 368
61 2 9372 4852/ +61 447 029 368
New CACTI AAT image of the neighbourhood of SN1987A. Credit: Ángel R. López-Sánchez (AAO/MQU), Steve Lee, Robert Patterson, Robert Dean and Jennifer Riding (AAO) & Sarah Martel (UNSW/AAO).
Exactly 30 years ago, humans witnessed the first supernova explosion visible to the unaided eye in almost 400 years. The event provided an unprecedented opportunity for the 3.9metre Anglo-Australian Telescope (AAT), which went on to play a key role in the study of Supernova 1987A.
The stellar outburst seen in 1987 on Earth resulted from the explosion of a massive star called Sanduleak -69° 202 in the Large Magellanic Cloud, one of our closest galaxy neighbours and only visible from the southern hemisphere. Light from the explosion had taken 170,000 years to travel through space before hitting terrestrial telescopes.
Once alerted to news of the supernova in February 1987, astronomers and engineers working at the Australian Astronomical Observatory immediately devised plans for how to make the best observations with the AAT. Observing the supernova became a top priority for the next three weeks, the assumed time that it would remain bright.
But just in case the supernova continued to be visible, AAO’s Peter Gillingham rapidly assembled a very high resolution “Wooden Spectrograph”, since no telescope in the southern hemisphere at the time had this type of technology available to take advantage of observing such a rare, bright supernova. With luck, Supernova 1987A remained observable for several months after it exploded.
Resulting observations hinted that this supernova explosion was not symmetric – it was clumpy and very unusual compared to previously observed exploded stars. This asymmetry was later confirmed in beautiful images taken with the Hubble Space Telescope (Figure 1 below).
Current AAO Director Warrick Couch was an AAO staff member at the time of the supernova’s appearance and recalls “from my perspective, it was an extraordinarily frantic and yet exhilarating time as the Observatory used its entire armoury of skills, inventiveness, and high-tech instruments to capture this remarkable and rapidly evolving event with the AAT.”
What does the neighborhood around Supernova 1987A look like today? AAO astronomer Angel Lopez-Sanchez captured a wide-field image of the region on 16th February 2017 with the new CACTI camera on the AAT (Figures 2 and 5 and see video). The image shows the remnant of Supernova 1987A, with the pink glow of its hydrogen gas, and filaments of gas and dust that stretch over 300 light years to either side.
The new image also reveals a group of pearl-like bubbles, 110 light years away from the explosion site. These bubbles are a sign of youth, indicating this fertile stellar nursery continues to form new stars.
Figure 1: The neighborhood and the remnant of SN 1987A.
Left: New image around the remnant of SN 1987A in the Large Magellanic Cloud taken with the 3.9m Anglo-Australian Telescope. Credit: Ángel R. López-Sánchez (AAO/MQU), Steve Lee, Robert Patterson, Robert Dean and Jennifer Riding (AAO) & Sarah Martel (UNSW / AAO). Top right: Wide Hubble Space Telescope image of the central area, data collected between 1994 and 1997. Credit: Hubble Heritage Team (AURA/STScI/NASA/ESA). Bottom right: Deep Hubble Space Telescope image obtained in 2011 showing the asymmetric structure of the SN 1987A remnant. Credit: ESA/Hubble & NASA.
Figure 3: Supernova 1987A after exploding in February 1987 (left), and an image taken before the explosion (right).
Credit: David Malin / Australian Astronomical Observatory.
Figure 4: The Tarantula Nebula loom to the upper left of where the star Sanduleak -69° 202 exploded as supernova 1987A.
Credit: David Malin / Australian Astronomical Observatory.
igure 5: New CACTI AAT image of the neighbourhood of SN1987A
Diffuse gas and dust in the outskirts of the Tarantula Nebula within the Large Magellanic Cloud. The remnant of SN 1987A appears as a bright red blob near the centre of the image. Data taken on 16th February 2017 using the CACTI camera in 2dF at the 3.9m Anglo-Australian Telescope. A Hubble Space Telescope (HST) image is included at the position where SN 1987A is located. Credit: Ángel R. López-Sánchez (AAO/MQU), Steve Lee, Robert Patterson, Robert Dean and Jennifer Riding (AAO) & Sarah Martel (UNSW / AAO).
Acess mp4nvideo here .
This 40 seconds animation shows a zooming into the SN1987A remnant in the Large Magellanic Cloud. It compiles 4 images: the full view of the Tarantula Nebula, as seen by the AAT years before the explosion on 23 February 1987, a new image of the neighbourhood of the supernova obtained with the new CACTI camera at the AAT, and wide and deep images obtained with the Hubble Space Telescope showing the asymmetry of the SN 1987A remnant.
Credit: Australian Astronomical Observatory. Credit of the composition: Ángel R. López-Sánchez (AAO/MQU). Credit of the individual images: Tarantula Nebula with the AAT: David Malin (AAO), CACTI image with the AAT: Credit: Ángel R. López-Sánchez (AAO/MQU), Steve Lee, Robert Patterson, Robert Dean and Jennifer Riding (AAO) & Sarah Martel (UNSW / AAO), Wide Hubble Space Telescope image: WFPC2, Hubble Heritage Team (AURA/STScI/NASA/ESA), Deep Hubble Space Telescope image: ACS, ESA/Hubble & NASA.
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The Australian Astronomical Observatory, a division of the Department of Industry, Innovation and Science, operates the Anglo-Australian and UK Schmidt telescopes on behalf of the astronomical community of Australia. To this end the Observatory is part of and is funded by the Australian Government. Its function is to provide world-class observing facilities for Australian optical astronomers.