analyzing 10 years of spectra of Vega detected a candidate 2.43-day signal around Vega, statistically estimated to have only a 1% chance of being a false positive. Considering the amplitude of the signal, the authors estimated a minimum mass of Earth masses, but considering the very oblique rotation of Vega itself of only 6.2° from Earth's perspective, the planet may be aligned to this plane as well, giving it an actual mass of Earth masses. The researchers also detected a faint -day signal which could translate to a Earth masses ( at 6.2° inclination) but is too faint to claim as a real signal with available data. Etymology and cultural significance The name is believed to be derived from the Arabic term Al Nesr al Waki النسر الواقع which appeared in the Al Achsasi al Mouakket star catalogue and was translated into Latin as Vultur Cadens, "the falling eagle/vulture". The constellation was represented as a vulture in ancient Egypt, and as an eagle or vulture in ancient India. The Arabic name then appeared in the western world in the Alfonsine tables, which were drawn up between 1215 and 1270 by order of King Alfonso X. Medieval astrolabes of England and Western Europe used the names Wega and Alvaca, and depicted it and Altair as birds. Among the northern Polynesian people, Vega was known as whetu o te tau, the year star. For a period of history it marked the start of their new year when the ground would be prepared for planting. Eventually this function became denoted by the Pleiades. The Assyrians named this pole star Dayan-same, the "Judge of Heaven", while in Akkadian it was Tir-anna, "Life of Heaven". In Babylonian astronomy, Vega may have been one of the stars named Dilgan, "the Messenger of Light". To the ancient Greeks, the constellation Lyra was formed from the harp of Orpheus, with Vega as its handle. For the Roman Empire, the start of autumn was based upon the hour at which Vega set below the horizon. In Chinese, (), meaning Weaving Girl (asterism), refers to an asterism consisting of Vega, ε Lyrae and ζ1 Lyrae. Consequently, the Chinese name for Vega is (, ). In Chinese mythology, there is a love story of Qixi () in which Niulang (, Altair) and his two children (β Aquilae and γ Aquilae) are separated from their mother Zhinü (, lit. "weaver girl", Vega)