Home > Ephemeris Program, stars > 02/09/2016 – Ephemeris – The Dog Star has a pup

02/09/2016 – Ephemeris – The Dog Star has a pup

February 9, 2016

Ephemeris for Fat Tuesday, Tuesday, February 9th.  The Sun will rise at 7:52.  It’ll be up for 10 hours and 9 minutes, setting at 6:02.   The Moon, 1 day past new, will set at 7:39 this evening.

Sirius is the brightest night time star and is located in the southeast at 9 p.m. below and a bit left of Orion the Hunter.  We’ve visited Sirius once before this winter.  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 by famed 19th century telescope maker Alvan Clark in 1862 while testing a new telescope.  The Pup is a white dwarf star, as small as the Earth but with the mass of the sun, out of hydrogen fuel and slowly collapsing.

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

Addendum

Orion and his hunting dogs

Orion and his hunting dogs revealed in animation. Created with Stellarium and GIMP.

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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