55 Cancri A

55 Cancri A is a yellow-orange star like the Sun, Sol.

UAE: Sonne, system

55 Cancri A

55 Cancri A is a yellow-orange main sequence dwarf star of spectral and luminosity type G8 V (that has been classed as orange as K0), with around 90.5 to 96 percent of Sol's mass (von Braun et al, 2011; Fischer et al, 2007; Takeda et al, 2007; and Winn et al, 2011), 94 to 110 percent of its diameter (von Braun et al, 2011; Demory et al, 2011, Table 1, page 3; van Belle and von Braun, 2009; and Baliunas et al, 1997), and around 60 (57 to 62) percent of its bolometric luminosity (Fischer et al, 2007). The star is now estimated to around twice (204 percent) as enriched as Sol with elements heavier than hydrogen ("metallicity") based on its abundance of iron, where metal enrichment may have been primordial (Fischer et al, 2007; Marcy et al, 2002, in pdf; Baliunas et al, 1997), and Santos et al, 2001). Chromospherically "inactive" with a rotation period of 39 days (Fischer et al, 2007, it appears to be a middle-aged dwarf of between two to eight billion years old, possibly around 5.5 billion years old based on chromospheric activity (Saffe et al, 2005, Table 4, page 8; Marcy et al, 2002, in pdf; and Baliunas et al, 1997). Based on isochrone fitting, however, the star appears to be 10.2 +/- 2.5 billion years old (von Braun et al, 2011). According to the Yale Bright Star Catalogue, 1991 5th Revised Edition notes entry for HR 3522, enhanced CN and C2 and perhaps CH has been detected in its spectrum. 55 Cancri A has a widely separated, dim companion Star ("B") located about 1,100 AUs (85" at 40.9 ly) away that seems to be gravitationally bound to it. Useful catalogue numbers and designations for the star include: 55 Cnc, Rho1 Cnc, Rho Cnc, HR 3522*, Gl 324, Hip 43587, HD 75732, BD+28 1660, SAO 80478, LTT 12310, LHS 2062, and LFT 609.

Cancri (abbreviated 55 Cnc) is a binary star approximately 41 light-years away from Sol

The system is the home system of the Falkenhorst society. Falkenhorst is the name of the main planet and the society. The sun is named Sonne. See also Sonne, system

Pre Astro: On October 11, 2012, a team of astronomers revealed that new analysis of recent observations and measurement of its radius indicate that planet "e" orbiting 55 Cancri A is composed of at least one third carbon. While this super-Earth's surface is likely composed of graphite, underneath that may be a thick layer of diamond over a deeper layer of silicon-based minerals and a molten core of iron. As the host star has more carbon than oxygen compared with our Sun, Sol, the astronomers were able to confirm that substantial amounts of carbon and silicon carbide but only a "negligible amount" of water ice were available during the planet’s formation, contrary to a previous hypothesis that planet e contained a substantial amount of super-heated water derived from the assumption that its chemical makeup was similar to that of Earth. The new research suggests the planet is composed primarily of carbon (as graphite and diamond), iron, silicon carbide, and possibly some silicates, and that at least a third of the planet's mass — the equivalent of about three Earth masses — could be made of diamond

On May 8, 2012, astronomers working with NASA's Spitzer Space Telescope revealed that they had directly detected infrared light from the innermost planet "e" around 55 Cancri A. They were able to determine that the tidally-locked planet is relatively dark and that its star-facing side is heated to more than 2,000 Kelvin (3,140 degrees F or 1,730 degrees C). The new observations indicate that the planet is composed of some 20 percent in light elements, which supports the hypothesis that the planet is a "water world," where a large rocky core is surrounded by a layer of very hot water under tremendous presssure in a "supercritical" state (where it is both liquid and gas) under a layer of steam -- similar to GJ 1214 b

On July 11, 2011, a team of astronomers submitted a paper which revised the estimated habitable zone of 55 Cancri A to between 0.67 and 1.32 AUs. The paper also confirmed that planet "f" "spends the majority of duration of its elliptical orbit in the circumstellar habitable zone, where moderate green house heating, were, with moderate greenhouse heating, it could harbor liquid water." As the planet probably has around 57 Earth-masses, however, it is likely to a gas giant, although it could have a habitable moon given sufficient mass (von Braun et al, 2011; and Phil Plait, Discover - Bad Astronomy blog, July 20, 2011).

On April 28, 2011, a team of astronomers revealed new analysis of innermost planet "e" (or "a4") around 55 Cancri A using the transit method, which indicated that the planet is roughly twice as dense as Earth. Using the CSA's "MOST" (Microvariability and Oscillation of Stars) space telescope, the team determined that the planet is 63 percent larger (1.63 +/- 0.16) in diameter (21,000 kilometers or 13,000 miles) and eight times (8.57 +/- 0.64) as massive as Earth. As a result, the planet has been determined to be the densest planet detected thus far, where a Human being would weigh some three times as heavy on its surface as he or she would on Earth (U. of British Columbia media release; Winn et al, 2011; and John Voisey, Universe Today, May 1, 2011).