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Ephemeris: 02/19/2026 – The star called Pup

February 19, 2026 Comments off

This is Ephemeris for Thursday, February 19th. Today the Sun will be up for 10 hours and 40 minutes, setting at 6:17, and it will rise tomorrow at 7:35. The Moon, 2 days past new, will set at 9:05 this evening.

Sirius is the brightest nighttime star and is located in the south at 9 p.m. below and a bit left of Orion the Hunter. We’ve visited Sirius last Monday, 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 as the heart of Canis Major, Orion’s larger hunting dog. The tiny star was suspected as far back as 1834 due to Sirius’ wavy path in the sky 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, with the mass of the Sun, is packed into the volume of the Earth.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.

Addendum

Orion's belt points to Sirius
In the southern sky, Orion’s belt points to Sirius. Created using Stellarium, LibreOffice Draw and GIMP.
Sirius and the Pup's path through the sky
Sirius A & B’s path in the sky showing the wobble that betrayed the Pup’s presence. Credit Mike Guidry, University of Tennessee.
The orbits of Sirius A and B about their center of mass
The orbits of Sirius A and B about their center of mass. The represented scale of the sizes of the two stars are also. Sirius A is twice the mass of the Sun, and 1.7 times it’s diameter. Sirius B (Pup) has the mass of the Sun, and about 0.008 times the size of the Sun, or about the size of the Earth.
Two views of Sirius and the Pup
Sirius A and B imaged by two different space telescopes, revealing dramatically different views! Hubble’s image (left) shows Sirius A shining brightly in visible light, with diminutive Sirius B a tiny dot. However, in Chandra’s image (right) tiny Sirius B is dramatically brighter in X-rays! The “Universe in a Different Light” activity highlights more surprising views of some familiar objects: http://bit.ly/different-light-nsn NASA, ESA, H. Bond (STScI), and M. Barstow (University of Leicester) (left); NASA/SAO/CXC (right)
A plot of many observations of Sirius B's position around Sirius A.
A plot of many observations of Sirius B’s position around Sirius A, color coded by the method of observation. Those from the Hubble Space Telescope (HST) are the most accurate. Credit: The Sirius System and Its Astrophysical Puzzles: Hubble Space Telescope and Ground-based Astrometry
by Howard E. Bond et al 2017 ApJ 840 70.

Categories: Ephemeris Program, Stars Tags: ,