Used to a kind of popular topic in the astronomical community back in the 60's. [1][2][3] [1] 1962, https://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_qu

Used to a kind of popular topic in the astronomical community back in the 60's. [1][2][3] [1] 1962, https://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1962ApJ...136..315B&classic=YES https://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_que... [2] 1967, https://adsabs.harvard.edu/pdf/1967lts..conf..160A https://adsabs.harvard.edu/pdf/1967lts..conf..160A [3] 1967, https://www.jstor.org/stable/40674487 https://www.jstor.org/stable/40674487 People still write about the potassium abundance in stars, just not quite so much publication in recent decades. [4][5] [4] 2002, https://academic.oup.com/pasj/article-abstract/54/2/275/2135739?redirectedFrom=PDF https://academic.oup.com/pasj/article-abstract/54/2/275/2135... [5] 2012, https://academic.oup.com/pasj/article-abstract/64/2/38/1482339?redirectedFrom=PDF https://academic.oup.com/pasj/article-abstract/64/2/38/14823...