`Oumuamua: Testing the Solid Hydrogen Theory

The discovery of the first interstellar asteroid, 1I/2017 U1 ('Oumuamua), has opened a new era for research on interstellar objects. A number of mysteries were raised by the 2017 discovery of ‘Oumuamua, the first interstellar object detected visiting our solar system. Chief among these: what caused ‘Oumuamua’s unexpected non-gravitational acceleration as it sped away from the Sun and off into space? One posited theory was that this interstellar asteroid was actually a hydrogen iceberg. A composition of hydrogen ice could explain the asteroid’s unusual, elongated shape, and sublimation of this ice could drive its extra acceleration. But Hoang and Loeb’s analysis shows that an ‘Oumuamua-sized hydrogen iceberg would be destroyed within 10 million years by starlight heating. Collisional heating would also rapidly wear at such an object in its birthplace, potentially destroying it before it could escape into the interstellar medium and journey to our solar system. And even the formation of such a hydrogen iceberg seems unlikely: Hoang and Loeb show that it is difficult to form icy grains rich in molecular hydrogen in the dense clouds that could birth an interstellar asteroid.

Spinup and Disruption of Interstellar Objects

The discovery of the first interstellar asteroid, 1I/2017 U1 ('Oumuamua), has opened a new era for research on interstellar objects. In this project, we aim to understand the evolution of ISAs by study the rotational dynamics of interstellar asteroids (ISAs) of irregular shapes moving through the interstellar gas.

Publications

  1. Thiem Hoang, Abraham Loeb, Destruction of molecular hydrogen ice and Implications for 1I/2017 (`Oumuamua), ApJL, 899, L23
  2. Hoang Thiem , Loeb Avi, Lazarian A., and Cho J., Spinup and Disruption of Interstellar Asteroids by Mechanical Torques, and Implications for 1I/2017 U1 ('Oumuamua), 2018, ApJ, 860, 42
  3. Hoang Thiem, and Loeb, A., Electromagnetic forces on a relativistic spacecraft in the interstellar medium , 2017, ApJ, 848, 31
  4. Hoang Thiem, Relativistic Gas Drag on Dust Grains and Implications , 2017, ApJ, 847, 77
  5. Hoang Thiem, Lazarian, A., Burkhart, B., and Loeb, A., The interaction of relativistic spacecrafts with the interstellar medium , 2017, ApJ, 837, 5, arXiv:1608.05284