ARCTURUS (ALPHA (α) BOOTIS)
RED GIANT STAR

Right Ascension:
14h 15m 39s

Best Seen:
5/1 - 9/1

Declination:
19º 10' 57"

Magnitude:
-0.06

Computer File:
arcturus

Constellation:
Bootes

Actual

Compared to Sun

Distance

37 l.y.

--

Actual Brightness

--

--

Surface Temperature

7,500 ºF

0.74

Diameter

20 million miles

25

Mass

--

1.5

Surface Gravity

--

--

Surface Composition (by mass)

74% hydrogen 24% helium 2% everything else

same

Spectral Type

K2 III

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Density (gram/cubic cm)

--

--

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

  1. Recommended eyepiece: 24mm or 40 mm.

  2. When people look through the telescope a bright reddish-orange point of light should be seen.

ARCTURUS INFORMATION:

  1. Arcturus is the 2nd brightest star in the Northern Hemisphere’s night sky (3rd brightest when including the Southern Hemisphere’s bright stars.)

  2. Arcturus became famous when its light was used to open the 1933 World’s Fair in Chicago. That light had left Arcturus at about the same time as the previous Chicago Fair in 1893.

  3. Arcturus may have a companion, only four times as luminous as the sun. However, this is unconfirmed.

Item
Updated Notes

Coordinates 01-06-2003
tweaked a bit

Distance
01-06-2003
OK with Scott’s The Flamsteed Collection and SIMBAD – NOTE: this is a combined mag of the two components

Actual Brightness
01-06-2003
previously said 115 – BUT Scott’s Flamsteed says there are two stars with different luminosities. However, I can’t find support for this companion anywhere else

Surface Temperature 01-06-2003
close enough to source which says precisely defined at 4290 K http://www.astro.uiuc.edu/projects/sow/arcturus.html

Diameter
01-06-2003
matches with http://www.astro.uiuc.edu/projects/sow/arcturus.html

Mass
01-06-2003
previously said 4 – but site says 1.5 http://www.astro.uiuc.edu/projects/sow/arcturus.html

Surface Gravity

Surface Composition 01-06-2003
OK for all stars

Spectral Type
01-06-2003
OK with Scott’s Flamsteed

Density 01-06-2003
previously said: .0003 times sun – BUT can find no support for this

Other Information
01-06-2003
World’s Fair info from http://www.astro.uiuc.edu/projects/sow/arcturus.html Companion info from Scott’s Flamsteed