Brian May, the multimillionaire guitarist who founded the rock group Queen, has finally completed the PhD in astrophysics that he abandoned more than 30 years ago.

The 59-year-old composer of hits such as Fat Bottomed Girls and We Will Rock You turned his back on the stars for international fame with Freddie Mercury and his band. His thesis on interplanetary dust clouds lay gathering dust of its own in the attic of his home in Surrey.

May’s interest in the subject was rekindled last year when he co-authored a children’s science book with the astronomer Sir Patrick Moore. He discovered that remarkably little research had been done in the intervening 33 years.

He dug out his old handwritten notes and spent nine months conducting further research at Imperial College, London, where he had studied before Queen hit the big time.

May revealed his achievement when he received an honorary doctorate at Exeter University this week. He told students: “For the last nine months I’ve done nothing except slave over my PhD, which is now written up, thank God. But there are times when you really want to give up. There are times when you go, ‘Why on earth did I take this on?’ ”

After the ceremony he said: “I worked on my thesis at Imperial from 1971 to 1974 when I had to give it up because Queen became a full-time thing. I kept all my notes and I was able to find them in my loft and start working on them again.”

Using a giant telescope in the Canary Islands, May was able to show for the first time that dust clouds in the solar system are moving in the same direction as the planets. He will receive his PhD next May, provided that his thesis is approved by assessors.

Abigail Smith, a spokeswoman for Imperial College, said: “People are aware he is here and there is a feeling it is pretty cool that he has come back to finish his PhD, even if he has not been hugely visible.”

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