x <- 1:24
Tmin <- x / (24*60*365) # use <- to create a new object, = to set a parameter
Tmin
#> [1] 1.902588e-06 3.805175e-06 5.707763e-06 7.610350e-06 9.512938e-06
#> [6] 1.141553e-05 1.331811e-05 1.522070e-05 1.712329e-05 1.902588e-05
#> [11] 2.092846e-05 2.283105e-05 2.473364e-05 2.663623e-05 2.853881e-05
#> [16] 3.044140e-05 3.234399e-05 3.424658e-05 3.614916e-05 3.805175e-05
#> [21] 3.995434e-05 4.185693e-05 4.375951e-05 4.566210e-05
See the FAQ: How to do a minimal reproducible example reprex for beginners to repose the question in terms of Tmin.