TrES-2b 1

TrES-2b

TrES-2b

Extrasolar planet List of extrasolar planets

Artist's conception of TrES-2b, with unsubstantiated speculation on possible moons

Parent star

Star GSC 03549-02811 A[1]

Constellation Draco

Right ascension (α) 19h 07m 14.035s

Declination (δ) +49° 18′ 59.07″

Distance 750 ± 30 ly(230 ± 10 pc)

Spectral type G0V

Orbital elements

Semimajor axis (a) 003556 ± 000075[1] AU

Eccentricity (e) 0

Orbital period (P) 247063 ± 000001 d

Inclination (i) 8362 ± 014[1]°

Physical characteristics

Mass (m) 1199 ± 0052[1] MJ

Radius (r) 1272 ± 0041[1] RJ

Surface gravity (g) 3284 ± 0016[1] g

Discovery information

Discovery date August 21, 2006confirmed September 8, 2006

Discoverer(s) O'Donovan et al.

Detection method Transit

Discovery site California & Arizona

Discovery status Published

Other designations

TrES-2b 2

TrES-2b

Database references

Extrasolar PlanetsEncyclopaedia

data [2]

SIMBAD data [3]

TrES-2b (or Kepler-1b) is an extrasolar planet orbiting the star GSC 03549-02811 located 718 light years awayfrom our solar system. The planet has been identified in 2011 as the darkest known exoplanet, reflecting less than1% of any light that hits it.[4] The planet's mass and radius indicate that it is a gas giant with a bulk compositionsimilar to that of Jupiter. Unlike Jupiter, but similar to many planets detected around other stars, TrES-2b is locatedvery close to its star, and belongs to the class of planets known as hot Jupiters. This system is within the field of viewof the now operational Kepler spacecraft.[5]

This planet continues to be studied by other projects and the parameters are being improved continuously. A 2007study improved stellar and planetary parameters.[6] A 2008 study concluded that the TrES-2 system is a binary starsystem. This has a significant effect on the values for the stellar and the planetary parameters.[1]

Discovery

The radial velocity of GSC 03549-02811 overtime, caused by the presence of TrES-2 b.

TrES-2b was discovered on August 21, 2006 by the Trans-AtlanticExoplanet Survey (TrES) by detecting the transit of the planet acrossits parent star using Sleuth (Palomar Observatory, California) andPSST (Lowell Observatory, Arizona), part of the TrES network of10–cm telescopes. The discovery was confirmed by the W. M. KeckObservatory on September 8, 2006, by measuring the radial velocity ofthe star that hosts TrES-2b.[5]

Spin-orbit angle

In August 2008 more details of the relationship between the parent starand the orbit of the planet were published. The orbit was determined to be tilted by −9 ± 12 from the stellar equator.The orbital direction was determined to be in the same direction as the star's rotation (prograde).[7]

The Kepler missionNASA launched Kepler in March 2009. The spacecraft is dedicated to the discovery of extrasolar planets by thetransit method from solar orbit. In April 2009 the project released the first light images from the spacecraft, andTrES-2b was one of two objects highlighted in these images. Although TrES-2b is not the only known exoplanet inthe field of view of this spacecraft it is the only one identified in the first light images. This object is important forcalibration and check-out.[8]

TrES-2b 3

The GSC 03549-02811 system asseen from the Kepler spacecraft.

(Celestial north is toward the lowerleft corner and the subject is in thecenter of the photograph as seen

clearly in enlarged view.)

Darkest planet

The first important result from the Kepler Mission about TrES-2b is an extremelylow geometric albedo, measured in 2011.[4] If the entire day-night contrast weredue to geometric albedo, it would be 2.53%, but modeling suggests that much ofthis is dayside emission and the true albedo is much lower. It is estimated to beless than 1% and for best-fit model it is about 0.04%. This makes TrES-2b thedarkest known exoplanet, reflecting less light than coal or black acrylic paint.[9]

It is not clear why the planet is so dark. One reason could be an absence ofreflective clouds such as those which make Jupiter so bright, due to TrES-2b'sproximity to its parent star and the consequent high temperature. Another reasoncould be the presence in the atmosphere of light-absorbing chemicals such asvaporized sodium, potassium, or gaseous titanium oxide.[10] In general, hotJupiters are expected to be dark, because "absorption due to the broad wings ofthe sodium and potassium D lines is thought to dominate their visible spectra."Apart from that of Kepler-7b (38 ± 12), albedo measurements for hot Jupiters have generally given only upperlimits.[4]

References[1] Daemgen, S.; Hormuth, F.; Brandner, W.; Bergfors, C.; Janson, M.; Hippler, S.; Henning, T. (2009). "Binarity of transit host stars —

Implications for planetary parameters" (http:/ / www. mpia. de/ homes/ henning/ Publications/ daemgen. pdf) (PDF). Astronomy andAstrophysics 498 (2): 567–574. arXiv:0902.2179. Bibcode 2009A&A...498..567D. doi:10.1051/0004-6361/200810988. .

[2] http:/ / exoplanet. eu/ planet. php?p1=TrES-2& p2=[3] http:/ / simbad. u-strasbg. fr/ simbad/ sim-id?Ident=TrES-2+[4] David M. Kipping & David S. Spiegel. "Detection of visible light from the darkest world" (http:/ / www. astro. princeton. edu/ ~dsp/

PrincetonSite/ Home_files/ darkest_world. pdf). Monthly Notices of the Royal Astronomical Society. . Retrieved 2011-08-12.[5] O'Donovan, Francis T.; Charbonneau, David; Mandushev, Georgi; Dunham, Edward W.; Latham, David W.; Torres, Guillermo; Sozzetti,

Alessandro; Brown, Timothy M. et al. (2006). "TrES-2: The First Transiting Planet in the Kepler Field" (http:/ / www. iop. org/ EJ/ article/1538-4357/ 651/ 1/ L61/ 21047. html). The Astrophysical Journal Letters 651 (1): L61–L64. arXiv:astro-ph/0609335.Bibcode 2006ApJ...651L..61O. doi:10.1086/509123. .

[6] Alessandro Sozzetti et al. (August 1, 2007). "Improving Stellar and Planetary Parameters of Transiting Planet Systems: The Case of TrES-2"(http:/ / www. iop. org/ EJ/ article/ 0004-637X/ 664/ 2/ 1190/ 71636. html). The Astrophysical Journal 664 (2): 1190–1198. arXiv:0704.2938.Bibcode 2007ApJ...664.1190S. doi:10.1086/519214. .

[7] Winn, Joshua N.; Johnson, John Asher; Narita, Norio; Suto, Yasushi; Turner, Edwin L.; Fischer, Debra A.; Butler, R. Paul; Vogt, Steven S. etal. (2008). "The Prograde Orbit of Exoplanet TrES-2b" (http:/ / www. iop. org/ EJ/ abstract/ -search=62880448. 10/ 0004-637X/ 682/ 2/ 1283).The Astrophysical Journal 682 (2): 1283–1288. arXiv:0804.2259. Bibcode 2008ApJ...682.1283W. doi:10.1086/589235. .

[8] "Kepler Eyes Cluster and Known Planet" (http:/ / www. nasa. gov/ mission_pages/ kepler/ multimedia/ images/ fullFFIHot300. html). NASA.2009-04-16. . Retrieved 2009-05-09.

[9] "Coal-Black Alien Planet Is Darkest Ever Seen" (http:/ / www. space. com/ 12612-alien-planet-darkest-coal-black-kepler. html). Space.com. .Retrieved 2011-08-12.

[10] Baldwin, Emily (2011-08-11). "Exoplanet blacker than coal" (http:/ / www. astronomynow. com/ news/ n1108/ 11exo/ ). Astronomy Now. .Retrieved 2011-08-12.

TrES-2b 4

External links• Host to 'Hot Jupiter' (labeled) (http:/ / www. nasa. gov/ mission_pages/ kepler/ multimedia/ images/

TrES2Hot300. html) NASA, 2009-04-16• TrES-2: Most Massive Nearby Transiting Exoplanet (http:/ / www. astro. caltech. edu/ ~ftod/ tres/ tres2. html)• Jupiter-Sized Transiting Planet Found by Astronomers Using Novel Telescope Network (http:/ / pr. caltech. edu/

media/ Press_Releases/ PR12890. html)• Light curve for TrES-2b using differential photometry (http:/ / www. perseus. gr/

Astro-Photometry-TrES-2-20120529. htm)

Article Sources and Contributors 5

Article Sources and ContributorsTrES-2b  Source: http://en.wikipedia.org/w/index.php?oldid=516840408  Contributors: 83d40m, Aldaron, Aldebaran66, Andrewb1224, Article editor, Aréat, Ayrenz, Bryan Derksen, ChaheelRiens, Chaos syndrome, Cogiati, GenaroEnriqueMiguel, Harfarhs, Haruo, Hduckman, Hydrargyrum, Icalanise, James McBride, Jdos2, Jeff Silvers, Jenks24, Kanags, Mike s, Mmatessa, Murgh,NCDane, Nathan Johnson, Neitherday, Niri.M, Off2riorob, Originalwana, OverQuantum, PlanetStar, Prioryman, Punu, Quibik, Ringbang, Rjwilmsi, Roentgenium111, Salamurai, Sarfix5,Skamecrazy123, SkyLined, Smalljim, Speciate, Taelus, Telescopi, ThreeBlindMice, Tpbradbury, Tyrogthekreeper, Vegaswikian, Wayne Slam, Westley Turner, Wnt, WolfmanSF, Xelanared,Zimriel, 20 anonymous edits

Image Sources, Licenses and ContributorsImage:TrES-2b.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:TrES-2b.jpg  License: Creative Commons Attribution-Sharealike 3.0  Contributors: David A. Aguilar (CfA)Image:TrES-2 b rv.svg  Source: http://en.wikipedia.org/w/index.php?title=File:TrES-2_b_rv.svg  License: Attribution  Contributors: TrES-2_b_rv.pdf: This file was uploaded by JamesMcBride. derivative work: QuibikFile:Kepler First Light Detail TrES-2.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Kepler_First_Light_Detail_TrES-2.jpg  License: Public Domain  Contributors:NASA/Ames/JPL-Caltech

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