F-string, NS5-brane & D-string

[crackjack]

Is the fundamental string (F-string) same as an extremal 1-brane solution of su-gra-YM?
Can the same be said for the fundamental fivebrane (NS5-brane) and 5-brane?
Also, what kind of solution is a D-string?

 

[crackjack]

As a follow-up:

If F-strings & NS5-brane are different from extremal p-branes, then when p-branes are identified with as fundamental a construct as D-branes, how are F-strings & NS5-branes elevated?

If F-strings & NS5-brane are not different from extremal p-branes, what can we make out of these brane solutions in heterotic sugra when heterotic string theories are closed string theories (no open strings -> no branes to end on).

 

[crackjack]

I asked around and got the following answer:

F-string is the solitonic solution of SUGRA-YM equations coupled to the NS-NS 2-form (B-field), whereas D-string are solutions of equations with R-R 2-form couplings.
F-strings are elevated to the normal strings of string theory, whereas D-strings are the D1-branes.