US 708是一顆高速自轉，且擁有被認為來自原先和伴星交互作用而生成的厚層氦層恆星。這類主要組成成分為氦的恆星一般被認為是巨大恆星失去以氫為主的外層後所殘留。蓋爾的團隊描述US 708是「銀河系中最快的不受約束恆星」。並且使用位於夏威夷的口徑10米望遠鏡凱克Ⅱ的階梯式攝譜儀與成像儀觀測[11]，發現它的速度已經超過了銀河系的逃逸速度[12]。
Stephan Geier, F. Fürst, E. Ziegerer, T. Kupfer, U. Heber, A. Irrgang, B. Wang, Z. Liu, Z. Han, B. Sesar, D. Levitan, R. Kotak, E. Magnier, K. Smith, W. S. Burgett, K. Chambers, H. Flewelling, N. Kaiser, R. Wainscoat, C. Waters. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova. Science magazine. 2015-03-06 [2015-03-10]. （原始內容存檔於2015-09-24）. Hypervelocity stars (HVSs) travel with velocities so high that they exceed the escape velocity of the Galaxy.
Thermonuclear supernova ejects galaxy’s fastest star. Astronomy magazine. 2015-03-09 [2015-03-11]. （原始內容存檔於2020-11-09）. Scientists using the W. M. Keck Observatory and Pan-STARRS1 telescopes on Hawaii have discovered a star that breaks the galactic speed record, traveling with a velocity of about 2.7 million mph (1,200 km/s). This velocity is so high, the star will escape the gravity of our galaxy. In contrast to the other known unbound stars, the team showed that this compact star was ejected from an extremely tight binary by a thermonuclear supernova explosion.
US 708: Hypervelocity Star Ejected by Supernova Breaks Galactic Speed Record. Science News. 2015-03-06 [2015-03-10]. （原始內容存檔於2020-11-08）. A multinational team of astronomers led by Dr Stephan Geier from the European Southern Observatory in Garching, Germany, has determined that a hypervelocity star known as US 708 is traveling at about 1,200 km per second.
Douglas Quenqua. Fastest Star in the Galaxy Got an Unusual Start. New York Times. 2015-03-10: D4 [2015-03-10]. （原始內容存檔於2020-11-08）. By measuring the velocity, trajectory and rotation of the star, known as US 708, researchers at the European Southern Observatory determined that it started life as one half of a close binary pair — two stars that closely orbited one other.
