 Most stars are observed to be members of binary star systems , and the properties of those binaries are the result of the conditions in which they formed . A gas cloud must lose its angular momentum in order to collapse and form a star . The fragmentation of the cloud into multiple stars distributes some of that angular momentum . The primordial binaries transfer some angular momentum by gravitational interactions during close encounters with other stars in young stellar clusters . These interactions tend to split apart more widely separated ( soft ) binaries while causing hard binaries to become more tightly bound . This produces the separation of binaries into their two observed populations distributions . 
 Most stars are observed to be members of binary star systems , and the properties of those binaries <a href='drop_aux' title='1'><mark>are</mark></a>the result of the conditions in which they formed . A gas cloud must lose its angular momentum in order to collapse and form a star . The fragmentation of the cloud into multiple stars <a href='uninflect' title='2'><mark>distributes</mark></a> some of that angular momentum . The primordial binaries transfer some angular momentum by gravitational interactions during close encounters with other stars in young stellar clusters . These interactions tend to split apart more widely separated ( soft ) binaries while causing hard binaries to become more tightly bound . This <a href='uninflect' title='3'><mark>produces</mark></a> the separation of binaries into their two observed populations distributions . 
Most stars r observed to be members of binary star systems , and da properties of those binaries the result of the conditions in which they formed . A gas cloud must lose its angular momentum in order to collapse and form a star . The fragmentation of tdacloud into multiple stars distribute some of that angular momentum . Thdarimordial binaries transfer some angular momentum by gravitational interactions during close encounters wid other stars in young stellar clusters . dem interactions tend to split apart more widely separated ( soft ) binaries while causing hard binaries to become more tightly bound . dis produce the separation of binaries into their two observed populations distributions .