An outside team of astronomers have released the first orotund - scale map of the ages of various element at the center of the Milky Way and have established that the core of our galaxy was assembled over 4 billion yr ago . The study will be introduce at theEuropean Week of Astronomy and Space Science(EWASS ) in Liverpool .
The whitish Way is a spiral Galax urceolata that bulges in the center . This bulge is thou of light - years across and contains a quarter of the full stars of our galax . The historic period of the bulge has stupefy astronomer for awhile . Observations that used photometry , the color and brightness of star , witness evidence that it was old , but a spectroscopic proficiency , where the light of stars is analyzed in more detail , showed a significant fraction of young mavin .
In work to be submit to the journalAstronomy & Astrophysics , the squad used regular main - sequence stars that have play out fuels and are about to start burning heliumas an years investigation . Their findings suggest that a individual age can not be assumed for the core .
“ This is the first sentence that the years statistical distribution in the central constituent of the Milky Way , its bulge , is determined from deep photometric observation that cover both a wide area as well as sufficient depth such that we can map out the age - sensitive features : the principal - sequence negative stimulation stars , ” co - generator and European Southern Observatory astronomer Dr Marina Rejkuba , who will introduce the results at EWASS , told IFLScience .
The center of the Milky has two components – a spherical statistical distribution at the very essence made of older adept and an stretch bar made of younger objects . The team guess that the younger wiz are about 7 billion yr old . This is older than former observation have suggested but significantly younger than the 11 - billion - year - old star topology in the spherical core . This might aid us understand how the bar forge .
“ The Milky Way bar has constitute quite quick and has not been growing importantly through the gain of freshly mold stars since the past 7 billion years , ” Dr Rejkuba told IFLScience . “ Once the full mapping of the distribution of starring ages is double-dyed , the theorists who are build the numerical models of the Milky Way bulge formation will have Modern constraint for their models based on great statistics and wide area observation . ”
The work is part of the PhD research of Francisco Surot Madrid , who co - led the study with Dr Elena Valenti . The team desire to expand their observations as well as increase more data about the stars , like their apparent movement , to better understand how the bulge come to make .
