N2K Consortium

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The N2K Consortium is a collaborative multinational effort by American, Chilean and Japanese astronomers to find additional extrasolar planets around stars that are not already being surveyed. The N2K is shorthand for the set of roughly 2,000 of the nearest and most luminous main sequence stars that were selected to be newly surveyed. Target stars have a B - V color index value between 0.4 and 1.2, a visual magnitude brighter than 10.5, and a distance of less than 110  pc from the Sun. They were selected based upon their high metallicity, which is the abundance of elements other than hydrogen and helium. [1]

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The observing campaign uses the Keck, Magellan and Subaru telescopes, plus automated telescopes at Fairborn Observatory. Each star is observed three times over a period of several days, then checked for short period variations in radial velocity. This variation is a characteristic of gravitational perturbation caused by a hot Jupiter. Those stars showing radial velocity variations are then checked with the automated photometric telescopes from Fairborn Observatory. [1]

During a two-year run beginning in 2004, the N2K Consortium was predicted to detect about 60 new hot Jupiters. [1] However, by 2009, only seven planets with orbital periods of up to five days had been discovered. They orbit the following stars: [2]

See also

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HD 12661 Star in the constellation Aries

HD 12661 is a G-type main sequence star in the northern constellation of Aries. The star is slightly larger and more massive than the Sun, with an estimated age of seven billion years. It has two known extrasolar planets.

HD 88133 is an 8th magnitude star in the constellation of Leo. It is classified as a yellow main sequence star. It is slightly more massive than our Sun, cooler and more luminous. Located at a distance of 241 light years from Earth it is not in our immediate neighbourhood and thus not visible to the unaided eye. With a small telescope it should be easily visible.

HD 149026, also named Ogma, is a yellow subgiant star approximately 250 light-years from the Sun in the constellation of Hercules. An extrasolar planet is believed to orbit the star.

HD 149026 b Extrasolar planet in the constellation Hercules

HD 149026 b, formally named Smertrios, is an extrasolar planet approximately 250 light-years from the Sun in the constellation of Hercules.

HD 38529 is a binary star approximately 138 light-years away in the constellation of Orion.

HD 217107 b is an extrasolar planet approximately 65 light-years away from Earth in the constellation of Pisces. The planet was discovered orbiting the star HD 217107 approximately every seven days, classifying the planet as a hot Jupiter. Because of the planet's somewhat eccentric orbit, scientists were able to confirm another planet within the system.

HD 11506 b is an extrasolar planet that orbits the star HD 11506 167 light years away in the constellation of Cetus. This planet was discovered in 2007 by the N2K Consortium using the Keck telescope to detect the radial velocity variation of the star caused by the planet. A second planet, HD 11506 c, was discovered in 2015.

HD 189733 b Hot Jupiter extrasolar planet in the constellation Vulpecula

HD 189733 b is an exoplanet approximately 64.5 light-years away from the Solar System in the constellation of Vulpecula. The planet was discovered orbiting the star HD 189733 on October 5, 2005, when astronomers in France observed the planet transiting across the face of the star. With a mass 16.2% higher than that of Jupiter and a radius 13.8% greater, HD 189733 b orbits its host star once every 2.2 days at an orbital speed of 152.5 kilometres per second (341,000 mph), making it a hot Jupiter with poor prospects for extraterrestrial life. Being the closest transiting hot Jupiter to Earth, HD 189733 b is a subject for extensive atmospheric examination. The atmosphere of HD 189733b has been extensively studied through high- and low-resolution instruments, both from ground and space. HD 189733 b was the first extrasolar planet for which a thermal map was constructed, possibly to be detected through polarimetry, to have its overall color determined, to have a transit detected in X-ray spectrum and to have carbon dioxide detected in its atmosphere.

HD 109749 is a binary star about 206 light years away in the constellation of Centaurus.

HD 149143, formally named Rosalíadecastro, is a star located in Ophiuchus constellation that has spectral type of G0 located at a distance of 240 ly from us. Its apparent magnitude is 7.9 and the absolute magnitude is 3.9.

HD 88133 b is an extrasolar planet orbiting the star HD 88133. It is probably less massive than Jupiter and even Saturn. It orbits the star in a very tight orbit, completing one revolution around the star in every three and half days or so. Despite the relatively large radius of the star, no transits have been detected.

HD 109749 b is an extrasolar planet that orbits extremely close to the star HD 109749, taking only 5.24 days to orbit at the distance of 0.063 AU. This planet was discovered on August 22, 2005 - the same day as the discovery of Gliese 581 b.

HD 183263 b is an extrasolar planet orbiting the star HD 183263. This planet has a minimum mass of 3.6 times more than Jupiter and takes 625 days to orbit the star. The planet was discovered on January 25, 2005 using multiple Doppler measurements of five nearby FGK main-sequence stars and subgiants obtained during the past 4–6 years at the Keck Observatory in Mauna Kea, Hawaii. These stars, namely, HD 183263, HD 117207, HD 188015, HD 45350, and HD 99492, all exhibit coherent variations in their Doppler shifts consistent with a planet in Keplerian motion, and the results were published in a paper by Geoffrey Marcy et al. Photometric observations were acquired for four of the five host stars with an automatic telescope at Fairborn Observatory. The lack of brightness variations in phase with the radial velocities supports planetary-reflex motion as the cause of the velocity variations. An additional planet in the system was discovered later.

HD 149143 b Extrasolar planet

HD 149143 b, formally named Riosar, is an extrasolar planet that has a minimum mass of 1.33 Jupiter masses. As is typical for a lot of hot Jupiters, its orbital eccentricity is low.

HD 17156 b

HD 17156 b, named Mulchatna by the IAU, is an extrasolar planet approximately 255 light-years away in the constellation of Cassiopeia. The planet was discovered orbiting the yellow subgiant star HD 17156 in April 2007. The planet is classified as a relatively cool hot Jupiter planet slightly smaller than Jupiter but slightly larger than Saturn. This highly-eccentric three-week orbit takes it approximately 0.0523 AU of the star at periastron before swinging out to approximately 0.2665 AU at apastron. Its eccentricity is about the same as 16 Cygni Bb, a so-called "eccentric Jupiter". Until 2009, HD 17156 b was the transiting planet with the longest orbital period.

HD 16760 is a binary star system approximately 227 light-years away in the constellation Perseus. The primary star HD 16760 is a G-type main sequence star similar to our Sun. The secondary, HIP 12635 is 1.521 magnitudes fainter and located at a separation of 14.6 arcseconds from the primary, corresponding to a physical separation of at least 660 AU. Announced in July 2009, HD 16760 has been confirmed to have a red dwarf orbiting it, formerly thought to be a brown dwarf or exoplanet.

HD 30562 b is an extrasolar planet which orbits the F-type main sequence star HD 30562, located approximately 85.4 light years away in the constellation Eridanus.

References

  1. 1 2 3 4 Fischer, Debra A.; et al. (2005). "The N2K Consortium. I. A Hot Saturn Planet Orbiting HD 88133" (PDF). The Astrophysical Journal. 620 (1): 481. Bibcode:2005ApJ...620..481F. doi:10.1086/426810.
  2. ↑ Sato, Bun'ei; et al. (September 2009). "A Substellar Companion in a 1.3 yr Nearly Circular Orbit of HD 16760". The Astrophysical Journal. 703 (1): 671–674. arXiv: 0907.5080 . Bibcode:2009ApJ...703..671S. doi:10.1088/0004-637X/703/1/671. S2CID   5435270.
  3. 1 2 Fischer, Debra A.; et al. (2006). "The N2K Consortium. III. Short-Period Planets Orbiting HD 149143 and HD 109749". The Astrophysical Journal. 637 (2): 1094–1101. Bibcode:2006ApJ...637.1094F. doi: 10.1086/498557 .
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