Red-giant branch hydrogen fusion continues in stars of roughly solar mass until the helium core increases in mass sufficiently that it becomes degenerate. The core then shrinks, heats up, and develops a strong temperature gradient. The hydrogen shell, fusing via the temperature-sensitive CNO cycle, greatly increases its rate of energy production and the stars is considered to be at the foot of the red-giant branch. For a star the same mass as the sun, this takes approximately 2 billion years from the time that hydrogen was exhausted in the core. Subgiants more than about reach the Schönberg–Chandrasekhar limit relatively quickly before the
Red Hydrogen One price and flagship ambitions." In contrast, "The Verge" gave the Hydrogen One a score of 3 out of 10, arguing that it "fell short" of the quality expected among phones in its price range, and acknowledging the shortcomings of the features that were intended to set the Hydrogen One apart from them. Red Hydrogen One Red Hydrogen One is an Android smartphone manufactured by Red Digital Cinema. It was officially announced on May 18, 2018 with a release date in August 2018. and released in the United States via AT&T and Verizon Wireless on November 2, 2018 after multiple delays.