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Beta (β) Lyrae
Multiple Star System
| Right Ascension | 18h 50m 04s | Best Seen | 6/1 - 11/15 |
| Declination | 33° 21' 46" | Combined Magnitude | 3.52 |
| Apparent Separation | 44" | Constellation | Lyra |
Actual |
Compared to Sun |
|
| Distance | 881 ly | -- |
| Separation | -- | -- |
| Orbital Period | 12.9 days | -- |
| Actual Brightness | -- | 2247 / ? |
| Magnitude | 3.52 / ~8 | |
| Mass | -- | ~2 / ? |
| Surface Gravity | -- | -- |
| Surface Composition (by mass) | 74% hydrogen 24% helium 2% everything else |
same |
| Spectral Type | B7 Ve / B5 V | 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 they should see two stars next to each other. In this case the two stars should be about the same brightness.
Beta Lyrae Information:
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It’s uncertain whether the two stars we see are a multiple system or an optical double.
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The primary star is an eclipsing binary star.
a. Because of the unseen companion that passes in front, the brightness of the primary can change almost a magnitude every 12 days 22 hours.
b. The primary and its companion are so close they orbit each other in about 13 days.
c. They’re so close that their atmospheres are intermingling: the primary is losing matter to the unseen companion.
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The companion star is also a multiple star. It is a spectroscopic binary.
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References
| Item | Updated | Notes |
| -- | -- | -- |
| Apparent Separation | 2018-11-05 | supported by http://www.physics.sfasu.edu/astro/betalyra/index.html |
| Distance | 2002-08-26 | Bet Lyr A: parallax 3.70mas Bet Lyr B: parallax |
| Separation | 2002-08-26 | previous: 1.4 trillion miles? – BUT cannot find support |
| Orbital Period | 2002-08-26 | previous: “1,165 years” – BUT can’t find support |
| Actual Brightness | 2002-08-26 | putting together Scott’s The Flamsteed Collection and info about companion from http://www.seds.org/Maps/Stars_en/Fig/lyra.html |
| Magnitude | 2002-08-26 | 8th mag companion from http://www.seds.org/Maps/Stars_en/Fig/lyra.html |
| Mass | 2002-08-26 | previous: “31 / -(sun)” – BUT found better info at http://www.physics.sfasu.edu/astro/betalyra/index.html |
| Surface Gravity | -- | |
| Surface Composition | 2003-01-06 | OK for all stars |
| Spectral Type | 2002-08-26 | previous: “A8V / ?” – BUT Scott’s Flamsteed says “A8:Vcomp”, but think SIMBAD is correct. |
| Density | -- | |
| Other Information | 2002-10-22 | Sources: SIMBAD, http://www.seds.org/~spider/spider/Vars/betaLyr.html https://www.aavso.org/vsots_betalyr http://stars.astro.illinois.edu/sow/sheliak.html |