05/03/2022 – Ephemeris – Regulus, the “Little King Star”

This is Bob Moler with Ephemeris for Tuesday, May 3rd. Today the Sun will be up for 14 hours and 20 minutes, setting at 8:50, and it will rise tomorrow at 6:28. The Moon, 3 days past new, will set at 12:05 tomorrow morning.

Fairly high in the south-southwest at 10 p.m. is a pattern of stars that’s in the shape of a backward question mark. This informal star group or asterism is also called the sickle. It is the head and mane of the official zodiacal constellation of Leo the lion. To the left is a triangle of stars is his hind end. The bright star at the bottom of the question mark, or end of the sickle’s handle is Regulus, the “Little King Star”, alluding to the lion’s status as the king of the jungle. Regulus is about 79 light years away and is a 4 star system that exists as two star pairs. The bright star Regulus itself and a companion too close to be imaged directly in telescopes, and a nearby pair of dim stars make up the system. The Moon often passes in front of Regulus, since it’s close to the ecliptic. These occultations, as they are called, will occur monthly for a year and a half starting July

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

Animated finder chart for Leo and Regulus for early May at 10 pm or an hour after sunset. The orange line that appears is the ecliptic, the path of the Sun in the sky. The path of the Moon is tilted by about 5 degrees to that path. The paths cross at points called nodes. The nodes move slowly westward in an 18.6-year cycle called the regression of the nodes. Occultations of Regulus by the Moon occur during two periods in that cycle. The next period where occultations of Regulus will occur monthly from July 2025 to January 2027. Created using Stellarium and GIMP.

Occultations are like solar eclipses in that they can only be seen from a limited area. That area will shift southward during that period. Of the 21 occultations in that period, only 2 will be visible from the United States: February 3rd, and April 26th 2026.