HAT-P-9b

Last updated
HAT-P-9b / Alef
Exoplanet Comparison HAT-P-9 b.png
Size comparison of HAT-P-9b with Jupiter.
Discovery
Discovered by Shporer et al.
Discovery site Cambridge, Massachusetts
Discovery dateJune 26, 2008
Transit (SuperWASP)
Orbital characteristics
0.0528 ± 0.002 AU (7,900,000 ± 300,000 km)
Eccentricity ~0.0012
3.92289 ± 0.00004 d
Star HAT-P-9
Physical characteristics
Mean radius
1.4 ± 0.06 RJ
Mass 0.78 ± 0.09 MJ
Mean density
380  kg/m3 (640  lb/cu yd)
10.3  m/s2 (34  ft/s2)
1.05 g

    HAT-P-9b, formally named Alef, [1] is an exoplanet approximately 1500 light years away in the constellation Auriga. This planet was found by the transit method on June 26, 2008. It has a mass 78% that of Jupiter and a radius 140% that of Jupiter. As with most transiting planets, this planet is a hot Jupiter, meaning this Jupiter-like planet orbits extremely close to its parent star, taking only 3.92 days to orbit. [2]

    The study in 2012, utilizing a Rossiter–McLaughlin effect, have determined the planetary orbit is mildly misaligned with the rotational axis of the star, misalignment equal to -16±8°. [3]

    The name Alef was selected in the NameExoWorlds campaign by Israel, during the 100th anniversary of the IAU. Alef is the first letter in the Hebrew alphabet and also means bull. [1]

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    <span class="mw-page-title-main">HAT-P-2b</span> Extrasolar planet

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    <span class="mw-page-title-main">HAT-P-4b</span> Exoplanet orbiting HAT-P-4b in the constellation Boötes

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    <span class="mw-page-title-main">HAT-P-8b</span> Extrasolar planet in the constellation Pegasus

    HAT-P-8b is an extrasolar planet located approximately 720 light years away in the constellation of Pegasus, orbiting the 10th magnitude star GSC 02757-01152. This planet was discovered by transit on December 5, 2008. Despite the designation as HAT-P-8b, it is the 11th planet discovered by the HATNet Project. The mass of the planet is 50% more than Jupiter while the radius is also 50% more than Jupiter. The mass of this planet is exact since the inclination of the orbit is known, typical for transiting planets. This is a so-called “hot Jupiter” because this Jupiter-like gas giant planet orbits in a really close torch orbit around the star, making this planet extremely hot. The distance from the star is roughly 20 times smaller than that of Earth from the Sun, which places the planet roughly 8 times closer to its star than Mercury is from the Sun. The “year” on this planet lasts only 3 days, 1 hour, 49 minutes, and 54 seconds, compared with Earth's 365 days, 6 hours, 9 minutes, and 10 seconds in a sidereal year.

    HAT-P-8 is a magnitude 10 star located 700 light-years away in Pegasus. It is a F-type star about 28% more massive than the Sun. Two red dwarf companions have been detected around HAT-P-8. The first has a spectral type of M5V and has a mass of 0.22 M. The second is even less massive, at 0.18 M, and its spectral type is M6V.

    HAT-P-13, also known as GSC 03416-00543, is a G-type main sequence star approximately 800 light-years away in the constellation Ursa Major. In 2009 it was discovered that this star is orbited by two massive planets, the innermost of which transits the star. This was the first known example of an extrasolar transiting planet with an additional planet in the same system.

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    <span class="mw-page-title-main">HAT-P-14b</span> Exoplanet in the constellation of Hercules

    HAT-P-14b, also known as WASP-27b, is an extrasolar planet located approximately 224.2 ± 0.6 parsecs (731.2 ± 2.0 ly) away in the constellation of Hercules, orbiting the 10th magnitude F-type main-sequence star HAT-P-14. This planet was discovered in 2010 by the HATNet Project using the transit method. It was independently detected by the SuperWASP project.

    HAT-P-24 is an F8 dwarf star about 400 parsecs away. A planet was discovered with the transit method by the HATNet Project in 2010. HAT-P-24b, is a typical hot Jupiter orbiting in only 3 days.

    HAT-P-24b is an extrasolar planet discovered by the HATNet Project in 2010 orbiting the F8 dwarf star HAT-P-24. It is a hot Jupiter, with a mass three quarters that of Jupiter and a radius 20% larger.

    HAT-P-17 is a K-type main-sequence star about 92.6 parsecs (302 ly) away. It has a mass of about 0.857 ± 0.039 M. It is the host of two planets, HAT-P-17b and HAT-P-17c, both discovered in 2010. A search for a binary companion star using adaptive optics at the MMT Observatory was negative. A candidate companion was detected by a spectroscopic search of high-resolution K band infrared spectra taken at the Keck observatory.

    Kepler-13 or KOI-13 is a stellar triple star system consisting of Kepler-13A, around which an orbiting hot Jupiter exoplanet was discovered with the Kepler spacecraft in 2011, and Kepler-13B a common proper motion companion star which has an additional star orbiting it.

    HD 146389, is a star with a yellow-white hue in the northern constellation of Hercules. The star was given the formal name Irena by the International Astronomical Union in January 2020. It is invisible to the naked eye with an apparent visual magnitude of 9.4 The star is located at a distance of approximately 446 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −9 km/s. The star is known to host one exoplanet, designated WASP-38b or formally named 'Iztok'.

    HAT-P-15 is a G-type main-sequence star about 630 light-years away. The star is older than Sun yet has a concentration of heavy elements roughly 190% of solar abundance. The star has no noticeable starspot activity.

    References

    1. 1 2 "Approved names". NameExoworlds. Retrieved 2020-01-02.
    2. Shporer, Avi; et al. (2009). "HAT-P-9b: A Low-Density Planet Transiting a Moderately Faint F Star". The Astrophysical Journal. 690 (2): 1393–1400. arXiv: 0806.4008 . Bibcode:2009ApJ...690.1393S. doi:10.1088/0004-637X/690/2/1393. S2CID   930937.
    3. Albrecht, Simon; Winn, Joshua N.; Johnson, John A.; Howard, Andrew W.; Marcy, Geoffrey W.; Butler, R. Paul; Arriagada, Pamela; Crane, Jeffrey D.; Shectman, Stephen A.; Thompson, Ian B.; Hirano, Teruyuki; Bakos, Gaspar; Hartman, Joel D. (2012), "Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments", The Astrophysical Journal, 757 (1): 18, arXiv: 1206.6105 , Bibcode:2012ApJ...757...18A, doi:10.1088/0004-637X/757/1/18, S2CID   17174530

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