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Spica
Alpha (α) Virginis
Blue Star
| Right Ascension | 13h 25m 12s | Best Seen | 5/15 - 8/1 |
| Declination | -11° 09' 41" | Magnitude | 0.98 |
| Constellation | Virgo | ||
Actual |
Compared to Sun |
|
| Distance | 262 ly | -- |
| Actual Brightness | -- | 2,062 |
| Surface Temperature | ~36,000 ºF | ~3.6 |
| Diameter (average) | ~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
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Recommended eyepiece: 24mm or 40 mm.
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When people look through the telescope a bright bluish point of light should be seen.
Spica Information:
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Spica is the 10th brightest star in the Northern Hemisphere’s night sky (15th brightest when including bright stars in the Southern Hemisphere).
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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.
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References
| Item | Updated | Notes |
| Coordinates | 2002-07-22 | SIMBAD |
| Magnitude | 2002-07-22 | with Scott’s The Flamsteed Collection |
| Distance | 2002-07-22 | The Flamsteed Collection and SIMBAD |
| Actual Brightness | 2002-07-22 | The Flamsteed Collection |
| Surface Temperature | 2002-07-22 | assume B type stars top temp of 20,000K |
| Diameter2002-07-22 | with assumed temp of 20,000K | |
| Mass | 2002-11-20 | http://www.as.wvu.edu/~jel/skywatch/skw9605.html and http://chandra.harvard.edu/resources/faq/sources/snr/snr5.html |
| Surface Gravity | -- | |
| Surface Composition | 2003-01-06 | OK for all stars |
| Spectral Type | 2002-07-22 | SIMBAD |
| Other Information | 2002-07-22 | 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 | 2013-04-25 | changed to 74% / 24% / 2% |