The TW Hydrae association is a group of very young low-mass stars and substellar objects located approximately 25–75 parsecs (80–240 light years) from Earth. They share a common motion and appear to all be roughly the same age, 10±3 million years old. It is the youngest such association within 100 pc from Earth.[1]
As of 2017, 42 objects (in 23 systems[2]) are assigned to the association confidently, and several dozens — uncertainly. Masses of its known members vary from 5 Jupiter masses to 2 solar masses, and their spectral types vary from A0 to L7.[1]
Some of the best studied members of this stellar association are TW Hydrae (nearest known accreting T Tauri star to the Earth), HR 4796 (an A-type star with resolved dusty debris disk; the most massive known group member), HD 98800 (a quadruple star system with debris disk), and 2M1207 (accreting brown dwarf with remarkable planetary-mass companion 2M1207b).
Included in the association is WISEA 1147, which is a brown dwarf.[3][4][5]
