WASP-44b
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WASP-44b is a planet found in the orbit of WASP-44.
Discovery
Using the WASP-South station at the South African Astronomical Observatory, the SuperWASP project searched the night sky for transits, identifying WASP-44 as possible host to a transit event, in which a body crosses in front of its host star at a roughly periodic rate. This notice came about after WASP-South scanned the Cetus constellation between July and November 2009. In combination with later observations using both WASP-South and the SuperWASP-North in the Canary Islands, over 15,755 photometric measurements were collected. A later SuperWASP-North observational period between August and November 2010 produced a light curve of 6,000 data points. However, this light curve was not used to determine information about the system because it became ready during the time of the paper's preparation.[1] The star was observed at the same time as stars WASP-45 and WASP-46.[1]
In 2010, the European team of astronomers used the CORALIE spectrograph on the 1.2m Leonhard Euler Telescope at Chile's La Silla Observatory. The same radial velocity measurements detected by SuperWASP were detected. The planet WASP-44b was confirmed after analysis of the results ruled out spectroscopic binary stars, leaving a transiting planet as the most likely cause of the radial velocity variations.[1]
The Euler telescope was used to observe WASP-44b as it transited its host star. For 4.2 hours on September 14, 2010, Euler observed WASP-44 in search of a slight dimming in brightness until a more precise light curve could be found. Accounting for all data yet collected, analysis yielded the planet's characteristics.[1]
The discovery of WASP-44b, along with those of WASP-45b and WASP-46b, were reported on May 16, 2011 by the Royal Astronomical Society.[2]
Host star
WASP-44 is a sunlike G-type star in the Cetus constellation. WASP-44 has a mass of 0.951 solar masses and a radius of 0.927 solar radii, which means that WASP-44 is 95% the mass of and 92% the size of the Sun. With an effective temperature of 5410 K, WASP-44 is cooler than the Sun, although it is richer in iron, with a measured metallicity of [Fe/H] = 0.06 (1.15 times the amount of iron found in the Sun). The star is an estimated 900 million years old, although this age is uncertain, as error bars are large.[3] Based on its spectrum, WASP-44 is not active in its chromosphere (outer layer). The star was also not found to demonstrate a high rate of rotation.[1]
With an apparent magnitude of 12.9, WASP-44 cannot be seen with the unaided eye from Earth.[3]
Characteristics
WASP-44b is a Hot Jupiter with a mass of 0.889 times Jupiter's mass and a radius of 1.14 times that of Jupiter.[3] Although less massive than Jupiter, the planet is bloated to a greater size because its proximity to its host star heats it, a common effect in such closely orbiting gas giants.[1] WASP-44b orbits at a [[semimajor axis|mean distance] of 0.03473 AU, which is about 3% of the distance between the Earth and Sun. An orbit is completed every 2.4238039 days (58.171 hours).[3]
WASP-44b has an orbital inclination of 86.02º, which is almost edge-on as seen from Earth.[3]
References
- ^ a b c d e f
D. R. Anderson; et al. (2011). "WASP-44b, WASP-45b and WASP-46b: three short-period, transiting extrasolar planets". Royal Astronomical Society. Retrieved 30 May 2011.
{{cite web}}: Explicit use of et al. in:|author=(help) - ^ "arXiv preprint 1105.3179". ArXiv. Cornell University. 2011. Retrieved 30 May 2011.
- ^ a b c d e Jean Schneider (2011). "Notes for star WASP-44". Extrasolar Planets Encyclopaedia. Retrieved 30 May 2011.
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