Monday, April 28, 2008

LDS 720 ABC

Star type
g A (AU Microscopii): M0 V e
g B: (AT Microscopii A): M4.5 Vpe
g C: (AT Microscopii B): M4.5 Ve

Distance from Earth
g 32.42428 ly

Star Service No.
g NA

Age
g A: 12 million years (may be as young as eight and as old as 20 million years old)
g B: 12 million years
g C: NA

Diameter/Mass/Temp (xSol)
g A: 66.5%; 50%; NA
g B: 41%; 50% at best; NA
g C: 37%; 50% at best; NA

Brightness (xSol)
g A: 2.399%; an absolute luminosity of 10% as is a flare star
g B: 0.35%
g C: 0.35%

Metallicity
g A: NA
g B: NA
g C: NA

Comparison to Sol
g A: NA
g B: NA
g C: NA

Picture of star
g A: See upper right (photo courtesy of P. Kalas, University of California, Berkeley)
g B: NA
g C: NA

Star system features
g Belongs to 20 young stars now identified as being members of the Beta Pictoris moving group located around 10 to 50 parsecs (33 to 163 ly)

Known planets
g A: Evidence for a planet around based on the discovery of a hole in the star's young circumstellar dust disk; astronomers modelling the vertical thickness and dust production argue that its disk likely contains planetary embryos as large as Pluto that are undergoing runaway growth into larger bodies (one at an orbital distance of around 30 AUs); disk extends from around 35 to more than 100 AUs from the star; there is dust depletion within 12 AUs of the star, suggesting a planet in that area; dust disk is positioned head-on toward Earth
g B: NA
g C: NA

Habitable zone
g A: An Earth-type planet would be comfortable with liquid water would be centered around 0.3 AU, but star is too young to have developed planets ripe for life
g B: NA
g C: NA

Orbital map
g AU Microscopii is gravitationally bound to the 1.2 ly distant AT Microscopii AB. AT Microscopii's Stars A and B has an average separation (semi-major axis of 3.18") of 32.5 AUs. However, the eccentricity of the orbit (e= 0.256) moves the stars as close as 24.2 AUs but as far apart as 40.8 AUs. The two stars take around 209 years to complete an orbit around each other.

View from stars
g NA

Nearby stars
(Star systems with 10 light years)
g CD-27 14659 AB (K0-3 V ?): 5.5 ly
g AC+20 76187: 6.3 ly
g L 499-56: 9.2 ly

Map locating star system
g NA

Location in Earth sky
g Northwest corner of Constellation Microscopium, the Microscope, northwest of Alpha Microscopii, southwest of Omega Capricorni, south of Dabih (Beta1,2 Capricorni), and east of Ascella (Zeta Sagittarii)

Other names
g A: AU Microscopii; AU Mic; LDS 720 A; Gl 803; Hip 102409; HD 197481; CD-31 17815; CP(D)-31 6335; SAO 212402; LTT 8214; V 824
g B: AT Microscopii A; AT Mic A; Gl 799 A; Hip 102141; HD 196982; CD-31 16135 A; CP(D)-31 6181; SAO 212355; LTT 8181; LDS 720 B; U or UGP 502
g C: AT Microscopii B; AT Mic B; Gl 799 B; CD-31 16135 B; CP(D)-31 6181 B; LDS 720 C

Sci-fi mentions
g NA

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