A small planet is not necessarily a terrestrial planet. Planets that form beyond the snow line with loo little mass to seed rapid gas accretion (approx< 10 M_⊕) should be rich in volatile ices like H_2O and NH_3. Some of these planets should migrate inward by interacting with a circumstellar disk or with other planets. Such objects can retain their volatiles for billions of years or longer at ～1 AU as their thick steam atmospheres undergo slow hydrodynamic escape. These objects could appear in future surveys for extrasolar Earth analogs.
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