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Spica
SPICA (ALPHA (α) VIRGINIS)
BLUE STAR
Right Ascension:
13h 25m 12s
Best Seen:
5/15 - 8/1
Declination:
-11º 09' 41"
Magnitude:
0.98
Computer File:
spica
Constellation:
Virgo
Actual
Compared to Sun
Distance
262 l.y.
--
Actual Brightness
--
2,062
Surface Temperature
~ 36,000 ºF
~ 3.6
Diameter
~ 3.1 million miles
~ 3.5
Mass
--
~ 10
Surface Gravity
--
--
Surface Composition (by mass)
74% hydrogen 24% helium 2% everything else
same
Spectral Type
B1 III-IV
G2 V
Density (gram/cubic cm)
--
--
WHAT TO LOOK FOR THROUGH THE TELESCOPE:
-
Recommended eyepiece: 24mm or 40 mm.
-
When people look through the telescope a bright bluish point of light should be seen.
SPICA INFORMATION:
-
Spica is the 10th brightest star in the Northern Hemisphere’s night sky (15th brightest when including bright stars in the Southern Hemisphere).
-
Spica is an eclipsing binary star.
a. Spica’s companion is spectral type B2V.
b. The two stars orbit so closely they almost touch.
c. The two stars are so close they only take four days to complete an orbit.
Item
Updated
Notes
Coordinates
07-22-2002
SIMBAD
Magnitude
07-22-2002
with Scott’s The Flamsteed Collection
Distance
07-22-2002
The Flamsteed Collection and SIMBAD
Actual Brightness
07-22-2002
The Flamsteed Collection
Surface Temperature
07-22-2002
assume B type stars top temp of 20,000K
Diameter
07-22-2002
with assumed temp of 20,000K
Mass
11-20-2002
http://www.as.wvu.edu/~jel/skywatch/skw9605.html and http://chandra.harvard.edu/resources/faq/sources/snr/snr 5.html
Surface Gravity
Surface Composition
01-06-2003
OK for all stars
Spectral Type
07-22-2002
SIMBAD
Other Information
07-22-2002
07-22-2002 07-22-2002
07-22-2002
1. previous: mass = 15.5 times Sun –
BUT how know this?
2. brightness rank with Hipparcos
3. previous: density = 0.04 times Sun
– BUT how know this?
4. previous: close eclipsing binary,
80% of the light from larger star,
brightness range: 6.7%....
Secondary’s Mass: 6.8 Sun’s
mass. Secondary’s Diameter:
about 3 million miles... Separation
11 million miles; two stars almost
touching... Period of revolution:
0.174 days – BUT can’t find
support for all this
Surface Composition
4/25/2013
changed to 74% / 24% / 2%