TT_Aquilae
TT Aquilae
Star in the constellation Aquila
TT Aquilae (TT Aql) is a Classical Cepheid (δ Cep) variable star in the constellation Aquila.
The visual apparent magnitude of TT Aql ranges from 6.52 to 7.65 over 13.7546 days.[3] The light curve is asymmetric, with the rise from minimum to maximum brightness only taking half the time of the fall from maximum to minimum.[11]
TT Aql is a yellow-white supergiant around five thousand times brighter than the sun. It pulsates and varies in temperature between about 5,000 K and 6,000 K,[10] and the spectral type varies between F6 and G5. The radius is 91.4 R☉ at maximum brightness, varying between 84 R☉ and 100 R☉ as the star pulsates.[9]
Cepheid masses can be estimated using Baade-Wesselink relations and this gives 8.6 M☉. The mass estimated by matching to evolutionary tracks is 7.7 M☉. The mass calculated by modelling the pulsations is 6.2 M☉. The discrepancies between the masses obtained by the different methods occurs for most Cepheid variables.[8]