Chapter 1: Introduction to OSIRIS-REx

NASA's OSIRIS-REx spacecraft is engaged in a remarkable mission aimed at studying the asteroid Bennu and bringing back samples to Earth. Surprisingly, the mission has also advanced our knowledge about black holes. Although Bennu itself is not related to black holes, the X-ray instrument on OSIRIS-REx has detected a distant black hole adjacent to Bennu during a routine examination.

This mission's primary goal is to gather a small sample of regolith from Bennu, similar to what Japan’s Hayabusa2 probe accomplished. Given that opportunities to orbit asteroids are rare, NASA aimed to optimize the mission by employing various scientific instruments to analyze Bennu. One such instrument is the Regolith X-ray Imaging Spectrometer (REXIS), which evaluates how Bennu's surface reflects X-rays, providing insights into its composition. Interestingly, black holes are particularly active in the X-ray spectrum.

In November 2019, researchers observed a faint X-ray flare near Bennu. Further investigation confirmed that REXIS had identified a newly active black hole binary located approximately 30,000 light-years away. This object is likely a binary system consisting of a black hole and a main-sequence star. As material from the orbiting star spirals into the accretion disk, it heats up and emits energy, predominantly in the form of X-rays.

The black hole has been named MAXI J0637–430, as it was first detected by Japan’s MAXI X-ray telescope on the International Space Station (ISS). NASA's NICER instrument aboard the ISS later confirmed the X-ray flare detection. Subsequently, the OSIRIS-REx team observed MAXI J0637–430 with REXIS.

Earth's atmosphere obstructs most interstellar radiation, making space the only reliable venue for detecting objects like MAXI J0637–430. Instruments aboard the ISS and various orbital telescopes are crucial for such observations. This marks the first occasion that a black hole has been detected from interplanetary space.

NASA has pinpointed a landing site for OSIRIS-REx, where it will collect samples in the upcoming months. The team is meticulously verifying the mission plan before proceeding. If all goes well, OSIRIS-REx is anticipated to return its samples to Earth around mid-2023.

Chapter 2: Implications of the Discovery

The discovery of a black hole during an asteroid mission opens new avenues for research and understanding in astronomy. It highlights the potential for spacecraft to gather data about distant cosmic phenomena while pursuing their primary objectives. The implications of this finding extend beyond just the immediate mission, offering insights into the dynamics of black holes and their interactions with surrounding stars.

Now read: OSIRIS-REx is about to collect and return samples from an asteroid, NASA’s OSIRIS-REx Probe Reaches Asteroid Bennu, OSIRIS-REx Spots Unexplained Particle Ejections from Asteroid Bennu.