Sirius, a binary system, is the brightest star in the night sky. The larger of the two stars, Sirius A, is about 25 times brighter than the Sun, and Sirius is relatively close to less than 9 light-years away from our solar system.
On Monday night, for some areas in the South and Central America as well as the Caribbean, Sirius will likely disappear for a short time. This happens when a small asteroid passes in front of the star and cloaks it for up to 1.6 seconds, according to the International Occultation Timing Association. (Yes, the acronym is IOTA.)
In this case, the asteroid 4388 Jürgenstock has an apparent diameter that is only an iota larger than Sirius. The angular diameter of the asteroid is about 0.007 arc seconds (one arc second is 1/600 of the night sky), while the angled diameter of Sirius is 0.006 arc seconds. When the asteroid passes in front of Sirius, the star is briefly muted, perhaps completely, before lightening quickly. Sirius seems to blink slowly once.
Unfortunately, the path for this event is mostly over water. Based on maps from IOTA, occultation appears over clippings from Argentina and Chile, Panama, the head of Haiti and possibly Turks and Caicos. There remains a slight uncertainty in the timing that is expected to begin along its journey, which starts at 05:11 UTC and ends on Tuesday, February 19, at 05:26 UTC.
With a diameter of 4.7 km asteroid belt object was discovered in 1964 by an astronomer who – you guessed it – Jürgen Stock. This covering should give astronomers a rare opportunity to better characterize the dimensions of the asteroid. It is likely to have an irregular shape and further contribute to the uncertainty of how far it will block the light from Sirius.