AA under pressure HU

[chio]

first hand at this table

Party Poker
Blinds: $1/$2
9 players
Converter

Stack sizes:
UTG: $184.30
UTG+1: $244
MP1: $116.55
MP2: $112.19
MP3: $36.81
CO: $106.60
Button: $203.05
SB: $138.70
Hero: $200

Pre-flop: (9 players) Hero is BB with A[img]/images/graemlins/club.gif[/img] A[img]/images/graemlins/heart.gif[/img]
5 folds, CO calls, Button folds, SB calls, <font color="#cc0000">Hero raises to $8</font>, CO calls, SB folds.

Flop: 5[img]/images/graemlins/club.gif[/img] 9[img]/images/graemlins/spade.gif[/img] J[img]/images/graemlins/spade.gif[/img] ($18, 2 players)
<font color="#cc0000">Hero bets $12</font>, CO calls.

Turn: 5[img]/images/graemlins/spade.gif[/img] ($42, 2 players)
<font color="#cc0000">Hero bets $20</font>, <font color="#cc0000">CO raises to $40</font>

tough decision here. if i'm behind i don't have many outs. if i just call here i'll probably have to call a bigger bet on the river. if i 3bet i'll allow him to fold worse hands and call with better ones.

i can't really put him on a set here, the only thing i beat is AJ with As or J9. can i really put him on trip 5's or the flush here?

(1) minraise is a sign of strength
(2) feels too weak to fold here with overpair HU getting 5-1 immediate
(3) checking turn doesn't feel right either

help?