Unlike humans , stars do n’t have to put any effort into hold back their age — they are notoriously , and frustratingly , good at it . But we do partake in one affair in common : Starsslow downas they get older , a feature that scientist have been assume advantage of for some twelvemonth now . However , with a modified data point set , scientists havestruggledto make reliable reckoning .
Now , thanks to Kepler observations , scientist have finally demonstrated that they can accurately determine the eld of sun - like adept from how tight they are reel . Theirwork , which has been presented at a merging of the American Astronomical Society , make up a elephantine leap towards the ultimate end ofbuilding a clockthat can just valuate the ages of star from their spins .
Learning the age of a star is crucial for many astronomical studies , in special for the search of major planet outside our solar organization ( exoplanets ) , and of course extraterrestrial life . Given thatstars and planets form together , if we love the years of a star , we can determine the age of its planet . And the erstwhile the planet , thegreater the possibleness of find oneself lifeas it has had more time to get started .
scientist are peculiarly interested in stars like our own , or “ cool star . ” These are themost abundantstars in our galaxy and are also very bright . These galactic lamp posts also host the majority of Earth - like planets spotted so far . Unfortunately , these stars are tricky to historic period because their sizing and luminosity do n’t change much throughout most of their animation . But scientist have identify something that does deepen as a star grows sure-enough : its rotation , which gradually sire ho-hum .
fit in to the new body of work , there is aclose relationshipbetween a whiz ’s hatful , twisting and geezerhood , and if the first two can be quantify , the third can be calculated . To measure a star ’s spin , scientists depend at sullen patch , hollo hotshot spots , which travel across the Earth’s surface as it rotate . When uranologist look at distant asterisk , they ca n’t immediately see these dapple , so instead they seem for fall in brightness that occur when the spot appear .
Typically , these spots only dim a star ’s brightness by less than 1 % , meaning the changes are very difficult to assess . This is where NASA ’s Kepler spacecraft came to the rescue , which has provided precise measure of stellar luminousness since 2009 .
so as to calibrate their astral clock , scientists needed to value the spin period of whizz with known eld and multitude . Prior to this study , this had only been reach for sensation within a 1 - billion - twelvemonth - quondam cluster NGC 6811 , which rotated about once every 10 Day , and of course for our own 4.6 billion year old sun , which had a twirl menstruation of 26 solar day . Now , scientists have tally to this data set by measuring the spin of 30 sun - like mavin in a clustering know to be 2.5 billion year old , closing a “ four - billion - year - interruption . ” As account inNature , the stars in this clustering , NGC 6819 , sat beautifully in this gap , rotate around every 18 days .
Prior to this body of work , the ages of nerveless stars come with a margin of error as large as100 % ; now , this has been reduced to around 10 % .
[ ViaHarvard CfA , NatureandBBC News ]
