Left panel: Helium λ5877 absorption feature in TYC 4144 329 2 and nondusty main-sequence field F-type stars. These field F-type stars have He i λ5877 EWs of ~40 mÅ, while TYC 4144 329 2 has an He i λ5877 EW of ~290 mÅ. Such an enhanced He i absorption feature could be the result of superheated accreting material (Alencar & Basri 2000). Right panel: Hα complex in TYC 4144 329 2. The broad velocity width of the emission feature is consistent with a star that is accreting gas (White & Basri 2003). The deep central absorption component might in part be due to disk gas orbiting the star. Similar features are seen in the Hβ absorption line and the Na D absorption lines (see Section 3.3). Wavelengths in this figure are plotted in the heliocentric vacuum scale.