<Tr> <Th> Spectral type </Th> <Td> F7Ib </Td> </Tr> <Tr> <Th> U − B color index </Th> <Td> 0.38 </Td> </Tr> <Tr> <Th> B − V color index </Th> <Td> 0.60 </Td> </Tr> <Tr> <Th> Variable type </Th> <Td> Classical Cepheid </Td> </Tr>

What is the diameter of the north star