The Pleiades , also known as the “ Seven Sisters ” , is the sky ’s most far-famed virtuoso cluster . Yet even the name poses a mystery . The Kepler Space Telescope has been used to measure the variability of their brightness , changing our understanding of some of them and opening up new method for learning about other bright star . Eventually , this work may help us explain an oddity in the path ancient cultures worldwide described the bunch .
The Kepler Space Telescope allows us to tag the unclouded curve ball of variable stars with a preciseness Earth - based telescopes can not match . However , it is designed for search at faint principal , and its pixels become saturated when looking at stars as bright as those in the Pleiades . Dr Tim Whiteof Aarhus University in Denmark set out to find a technique to change that .
" The solution to observe bright stars with Kepler turned out to be rather bare , " White said in astatement . " We ’re chiefly concerned about relative , rather than absolute , changes in brightness . We can just measure these changes from nearby unsaturated picture element , and disregard the pure areas altogether . "
It ’s not quite as dewy-eyed as White makes it sound , however . The squad necessitate to make a method acting to burthen the light from each pixel to remove errors in the detector and allow for subtle movements of the satellite .
InMonthly Notices of the Royal Astronomical Society , White and his Centennial State - authors report that “ aureole photometry ” as they call their technique , can also be utile for ground base scope , since it allow measurements of mavin ’ luminance that apply few pixels and therefore manducate up less bandwidth when measuring many stars at once .
Using gloriole photometry on the seven brightest Pleiades , White substantiate six vary in brightness on a cycle of about one Earth - day . Some also show larger swing on longer fourth dimension - scales . Despite this , the variance patterns are very diverse , from smooth to quite high-strung .
The most distinctive is Maia , the fourth brightest of the Pleiades , which has a much slower , but also more regular , 10 - day rotary motion cycle . The authors attribute this to a large smirch with a concentration of elements such as atomic number 25 . Ironically , when such accurate measures were not uncommitted , astronomers think they saw much more short term fluctuation in Maia ’s igniter , which led them to make a family know as Maia variables . Other stars have since been put in this course , but Whitenoted : “ Our new observations show that Maia is not itself a Maia Variable ! "
The ancient Greeks key the bunch they name the Pleiades as seven houri pursued by Orion . Some Indigenous Australians had a signally like story . Almost every culture worldwide had itsown setof stories about these stars , but most agreed on their bit . Which is foreign , however , since there are not seven of them .
The Pleiades star clump actually contains more than a thousand stars , but most are far too light to see without a scope . Oddly though , there is a substantial gap in brightness between the sixth bright headliner , Taygeta , and the next three . therefore , depending on people ’s eyesight and the seeing condition , it ’s normal to be able to see six stars or nine , but not seven .
This match with Nipponese tradition , which describes them as six stars , now dramatise as the logo of Subaru , but most other cultivation distinguish seven . Indeed some myth name to one of the genius as conceal itself in shame , leading to conjecture that one of the cluster ’s fainter stars was once bright enough to win a place in unwritten tradition along with the current six .
So far , however , White ’s work has shed no light source on the possibleness of a evanesce 7th bright superstar .
Kepler ’s basal aim is to find satellite around other stars by see for regular dips in brightness . Despite its abundant success in other cases , Kepler did n’t find oneself planets around any of the Pleiades . Since these are young stars , just 125 million year old , there would certainly be no prospect of aliveness on such major planet even if they exist .
More significantly , however , White has designate that halo photometry is sensitive enough to detect planet spoil the face of very bright star topology , including our approximate neighbor such as Alpha Centauri .
