Celestial hemisphere:  Northern  ·  Constellation: Boötes (Boo)  ·  Contains:  7 Boo  ·  8 Boo)  ·  8 eta Boo  ·  HD120540  ·  HD120601  ·  HD121370  ·  HD121476  ·  HD121492  ·  HD121829  ·  IC 960  ·  IC 963  ·  IC 964  ·  IC 965  ·  Mufrid  ·  The star 7 Boo  ·  The star Muphrid (η Boo
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Eta Bootis - Muphrid, Joe Matthews
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Eta Bootis - Muphrid

Getting plate-solving status, please wait...
Eta Bootis - Muphrid, Joe Matthews
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Eta Bootis - Muphrid

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Description

Last night was relatively clear, but due to smoke transparency was poor or below average. However,  I am happy that I was able to get out and image in the time of clear sky available.

Eta Bootis - Muphrid
At magnitude 2.68, Muphrid or η Bootis is the 3rd-brightest star in the constellation Bootes, the Herdsman. Muphrid's name is mystifyingly obscure, Arabic for "the particular" or "alone".Muphrid lies directly to the west of Arcturus in our sky. Arcturus is in fact its closest stellar neighbor in space, as both stars are at nearly distances of 37 light years from our solar system. The two stars are about 3.24 light years apart, and each would appear brightly in the other's sky. Arcturus would appear at roughly magnitude -5.2 (close to twice the brightness of Venus) in Muphrid's night sky, while Muphrid would appear at about magnitude -2.5 (over twice the brightness of Sirius) in the sky of Arcturus.
Properties
The  star itself is of considerable interest. A class G0 subgiant star with a color and temperature (6100 K) close to the Sun's, it has started to evolve off the main sequence. From its distance of 37 light years, we find its luminosity to be only 9 times the Sun's - relatively dim for a naked-eye star. With its temperature, this yields a radius 2.7 times the Sun's, again indicative of an evolving star. With a mass about 1.5 suns, Muphrid has just ceased core hydrogen fusion. Its quiet helium core is surrounded by a shell of fusing hydrogen, and the star is just beginning to make the transition to a red giant.More unusual, Muphrid is a super-metal-rich star (where "metal" means "everything other than hydrogen and helium"). Its metal abundance is about twice the Sun's. η Boo is also surrounded by a hot, X-ray emitting corona, with a temperature of 3.5 million K - nearly twice as hot as the Sun's corona.
Components
Muphrid is also a spectroscopic binary, with a period of 494 days. However, its close companion, possibly an old white dwarf, has not been resolved through speckle interferometry. The two are separated by about the distance between Mars and the Sun. Muphrid also has a visible optical companion, a 9th-magnitude star 2' away, easily seen in small telescopes. This companion, however, is merely a line-of-sight coincidence.
[Adapted from STARS by Jim Kaler, Professor Emeritus of Astronomy, University of Illinois]

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Eta Bootis - Muphrid, Joe Matthews