Home > Ephemeris Program, stars > 02/08/2019 – Ephemeris – Sirius has a companion

02/08/2019 – Ephemeris – Sirius has a companion

February 8, 2019

Ephemeris for Friday, February 8th. Today the Sun will be up for 10 hours and 7 minutes, setting at 6:01, and it will rise tomorrow at 7:52. The Moon, half way from new to first quarter, will set at 9:48 this evening.

Sirius is the brightest night-time star and is located in the south-southeast at 9 p.m. below and a bit left of Orion the Hunter. We’ve visited Sirius yesterday. But there is another star in the Sirius system that is practically invisible due to Sirius’ dazzling glare. Its name is Sirius B, nicknamed the Pup, alluding to Sirius’ Dog Star title. The tiny star was suspected as far back as 1834 due to Sirius’ wavy path against the more distant stars. Sirius and the Pup have 50 year orbits of each other. The Pup was first seen in 1862. The Pup was the first of a new class of stars to be discovered, white dwarfs. The Pup is a dying star with the mass of the Sun, collapsed down to the size of the Earth.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


Orion's Belt points to Sirius

Orion’s Belt points to Sirius. Created using Stellarium.

Sirius' path

Sirius A & B’s path in the sky showing the wobble that betrayed the Pup’s presence. Credit Mike Guidry, University of Tennessee.

Sirius A and B

Sirius A and B (near the diffraction spike to the lower left), A Hubble Space Telescope photograph. Credit NASA, ESA.

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