The next supernova
ofWarwick,isthatthischangeablebehaviouris
notoutoftheordinaryforsupergiantstarswith
bubbling,cauldron-likesurfaces.“Betelgeusehas
hugeconvectioncellswhichproducesunspotsthat
couldeatourownSunwhole.It’sfairlylikelythat
thedimmingjustmeansithasmoresunspots
thannormal.”Guinangenerallyagrees– especially
asthedeclineinbrightnessappearstobe
bottomingout– thoughhealsounderstandsthe
renewedinterestinthestar.“It’sanunstablestar.
Butit’sdoingsomethingthatithasneverdonein
thelast 150 years.”
DoubtsovertheimmediacyofBetelgeuse’sbig
exitleavethedooropenfora widercommunityof
so-calledsupergiantprogenitorstarstostepinand
maketheirmarkonournightskies.Antares,the
redeyeoftheconstellationofScorpius,isa little
bitclosertousthanBetelgeuse,andata similar
stageinitslife.MuCepheiisfurtheraway,butat
doublethediameterofBetelgeusemaybecloserto
providinga ‘gueststar’akintoVenusinourdawn
andduskskies.
Furtherafield,StanwaypointstoEtaCarinae,
a binarystar,whichobservershavewitnessedThe Vera Rubin
Observatory
Under construction atop Chile’s Cerro
Pachón, the Vera C. Rubin Observatory,
formerly the Large Synoptic Survey
Telescope, will survey a huge area of the
Southern Hemisphere sky, providing data
for a wide range of scientific objectives.
For supernova scientists the value of the
VRO comes down to its ability to image
the entire sky repeatedly every few
nights, and to great depth. This means it
could spot hundreds of thousands of new
events. Within a minute of each change in
the sky, the VRO will alert the community
to respond, catching supernovae events
before they fade forever.4 Wide-anglelens
ontheuniverse
Tomaximiseitspotentialto
spotnewtransientphenomena
likesupernovae,theVROhas
a 3.5-degreefieldofview– the
SunasseenfromEarthisonly
0.5degreesacross.1 Panninga
largemirror
TheVRO’sreflecting
telescopecontains
an8.4-metre(28-
foot)primarymirror
thatcantrackacross
atsufficientpaceto
imagetheentiresky
everyfewnights.5 Multi-bandsurvey
TheVROwillcarryouta deepten-
yearimagingsurveyinsixbroad
opticalbandstomaximisethe
dataprovidedonanysupernovae
orprogenitorsimaged.throwing out its outer layers in 1837, 1887 and 1998.
Eta Carinae might be one of those rare stars which
could produce a gamma-ray burst or superluminous
supernova, though its distance poses no threat to
Earth. “They are all on the launchpad. They are all
unstable,” says Guinan, whose hedging is evidence
of the limitations science faces making any bolder
supernovae predictions.
“In some situations our simulations provide
the only insight of what the inside of a massive
star may look like in the moments before its core
collapses,” says Carl E. Fields, an astronomy PhD© LSST Project7 Acamerathesizeofacar
Imageswillberecordedbya 3.2-gigapixel
camera,thelargestdigitalcameraever
constructed.Itwilltakea 15-second
exposureevery 20 secondstohelpdetect
newhigh-energyevents.1
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