I show that the temperature of nuclear star clusters , starburst clusters in M82 , compact high- z galaxies , and some globular clusters of the Galaxy likely exceeded the ice line temperature ( T _ { Ice } \approx 150 - 170 K ) during formation for a time comparable to the planet formation timescale .
The protoplanetary disks within these systems will thus not have an ice line , decreasing the total material available for building protoplanetary embryos , inhibiting the formation of gas- and ice-giants if they form by core accretion , and prohibiting habitability .
Planet formation by gravitational instability is similarly suppressed because Toomre ’ s Q > 1 in all but the most massive disks .
I discuss these results in the context of the observed lack of planets in 47 Tuc .
I predict that a similar search for planets in the globular cluster NGC 6366 ( { [ Fe / H ] } = -0.82 ) should yield detections , whereas ( counterintuitively ) the relatively metal-rich globular clusters NGC 6440 , 6441 , and 6388 should be devoid of giant planets .
The characteristic stellar surface density above which T _ { Ice } is exceeded in star clusters is \sim 6 \times 10 ^ { 3 } { M _ { \odot } pc ^ { -2 } } f _ { dg, MW } ^ { -1 / 2 } , where f _ { dg, MW } is the dust-to-gas ratio of the embedding material , normalized to the Milky Way value .
Simple estimates suggest that \sim 5 - 50 % of the stars in the universe formed in an environment exceeding this surface density .
Caveats and uncertainties are detailed .