Search for OH 18 cm Radio Emission from 1I/2017 U1 with the Green Bank Telescope

• Published in: The Astronomical journal Vol. 155; no. 5; pp. 185 - 188
• Main Authors: Park, Ryan S., Pisano, D. J., Lazio, T. Joseph W., Chodas, Paul W., Naidu, Shantanu P.
• Format: Journal Article
• Language: English
• Published: Madison The American Astronomical Society 01.05.2018; IOP Publishing
• Subjects: ASTEROIDS; Astronomy; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Data reduction; DISTANCE; EMISSION; Interstellar space; minor planets, asteroids: general; minor planets, asteroids: individual (1I/2017 U1 ('Oumuamua)); PLANETS; Radio emission; radio lines: general; Radio telescopes; RESOLUTION; Spectral resolution; TELESCOPES; Upper bounds; VELOCITY
• ISSN: 0004-6256; 1538-3881; 1538-3881
• DOI: 10.3847/1538-3881/aab78d

This paper reports the first OH 18 cm line observation of the first detected interstellar object 1I/2017 U1 ('Oumuamua) using the Green Bank Telescope. We have observed the OH lines at 1665.402, 1667.359, and 1720.53 MHz frequencies with a spectral resolution of 357 Hz (approximately 0.06 km s−1). At the time of the observation, 'Oumuamua was at topocentric distance and velocity of 1.07 au and 63.4 km s−1, respectively, or at heliocentric distance and velocity of 1.8 au and 39 km s−1, respectively. Based on a detailed data reduction and an analogy-based inversion, our final results confirm the asteroidal origin of 'Oumuamua with an upper bound OH production of Q[OH] < 0.17 × 1028 s−1.