BETA (β) LYRAE
MULTIPLE STAR

Right Ascension:
18h 50m 04s

Best Seen:
6/1 - 11/15

Declination:
33º 21' 46"

Magnitude:
3.52

Computer File:
betalyr

Constellation:
Lyra

Apparent
Separation: 44"

Actual

Compared to

Distance

881 l.y.

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Separation

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Orbital Period

Actual Brightness

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2247 / ? (Sun)

Magnitude

3.52 / ~ 8

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Mass

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~ 2 / ? (Sun)

Surface Gravity

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Surface Composition (by mass)

74% hydrogen 24% helium 2% everything else

same (Sun)

Spectral Type

B7Ve / B5V

G2 V (Sun)

Density (gram/cubic cm)

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WHAT TO LOOK FOR THROUGH THE TELESCOPE:

  1. Recommended eyepiece: 24mm or 40 mm.

  2. 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 LYRA INFORMATION:

  1. It’s uncertain whether the two stars we see are a multiple system or an optical double.

  2. 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.

  1. The companion star is also a multiple star. It is a spectroscopic binary.

FOR GREG Here’s what the pages said before I researched Beta Lyra a bit.

1a. The primary star is itself a binary star. The two stars are large enough (15 ans 12 million miles across) ans so close to each other (22 million miles) that their atmospheres are intermingling.

1b. The larger star has the smaller mass - 11 times the sun’s amss, while the smaller star has the larger mass - 20 times that of the sun. The reason for this is unknown. 2. The secondary star also has a very faint companion that can only be detected with a spectroscope.

  1. There is a 5th member to the system that is 9th magnitude.

Item
Updated Notes

Apparent Separation

supported by http://www.physics.sfasu.edu/astro/betalyra/index.html

Distance
08-26-2002
Bet Lyr A: parallax 3.70mas Bet Lyr B: parallax

Separation
08-26-2002
previous: 1.4 trillion miles? – BUT cannot find support

Orbital Period
08-26-2002
previous: “1,165 years” – BUT can’t find support

Actual Brightness
08-26-2002
putting together Scott’s The Flamsteed Collection and info about companion from http://www.seds.org/Maps/Stars_en/Fig/lyra.html

Magnitude
08-26-2002
8th mag companion from http://www.seds.org/Maps/Stars_en/Fig/lyra.html

Mass
08-26-2002
previous: “31 / -(sun)” – BUT found better info at http://www.physics.sfasu.edu/astro/betalyra/index.html

Surface Gravity

Surface Composition 01-06-2003
OK for all stars

Spectral Type
08-26-2002
previous: “A8V / ?” – BUT Scott’s Flamsteed says “A8:Vcomp”, but think SIMBAD is correct.

Density

Other Information
10-22-2002
Sources: SIMBAD, http://www.seds.org/~spider/spider/Vars/betaLyr.html