I need assitance with transparency in r for data points on a map

I have a map created and need help with some data points. I am using basic r color ( no ggplot or yarrr). What I am doing is putting the points on top of the map code for points is..

points(x = X0_10cm_69_clay$lat, y = X0_10cm_69_clay$long,
       cex = X0_10cm_69_clay$MAE, pch = 19, col = "brown2",)

here is the map. I do want the red dots transparent.