TrES-1
Encyclopedia
TrES-1b is an extrasolar planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...

 approximately 512 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...

s away in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 of Lyra
Lyra
Lyra is a small constellation. It is one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations recognized by the International Astronomical Union. Its principal star, Vega — a corner of the Summer Triangle — is one of the brightest...

 (the Lyre
Lyre
The lyre is a stringed musical instrument known for its use in Greek classical antiquity and later. The word comes from the Greek "λύρα" and the earliest reference to the word is the Mycenaean Greek ru-ra-ta-e, meaning "lyrists", written in Linear B syllabic script...

). The planet's mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...

 and radius
Radius
In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its...

 indicate that it is a Jovian planet with a similar bulk composition to Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

. Unlike Jupiter, but similar to many other planets detected around other stars, TrES-1 is located very close to its star, and belongs to the class of planets known as hot Jupiter
Hot Jupiter
Hot Jupiters are a class of extrasolar planet whose mass is close to or exceeds that of Jupiter...

s. The planet was discovered orbiting around GSC 02652-01324
GSC 02652-01324
GSC 02652-01324 is an orange dwarf main sequence star approximately 512 light-years away in the constellation of Lyra .- Planetary system :...

 (an orange dwarf
Orange dwarf
A K-type main-sequence star , also referred to orange dwarf, are main-sequence stars of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence stars and yellow G-type main-sequence stars...

 star).

Detection and discovery

TrES-1b was discovered by the Trans-Atlantic Exoplanet Survey
Trans-Atlantic Exoplanet Survey
The Trans-atlantic Exoplanet Survey or TrES, uses three 4-inch telescopes located at Lowell Observatory, Palomar Observatory, and the Canary Islands to locate exoplanets. It was made using the network of small, relatively inexpensive telescopes designed to look specifically for planets orbiting...

 by detecting the transit
Astronomical transit
The term transit or astronomical transit has three meanings in astronomy:* A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, hiding a small part of it, as seen by an observer at some particular vantage point...

 of the planet across its parent star using a 4 inches (101.6 mm) telescope. The discovery was confirmed by the Keck Observatory. The planet was subsequently detected using the radial velocity
Radial velocity
Radial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity...

 method, allowing its mass to be determined.

Transit

On March 22, 2005, Astronomers using NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

's Spitzer Space Telescope
Spitzer Space Telescope
The Spitzer Space Telescope , formerly the Space Infrared Telescope Facility is an infrared space observatory launched in 2003...

 took advantage of this fact to directly capture the infrared light of two previously detected planets orbiting outside our solar system. Their findings revealed the temperatures and orbits of the planets.

Upcoming Spitzer observations using a variety of infrared wavelengths may provide more information about the planets' winds and atmospheric compositions. It enabled determination of TrES-1's temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

, which is in excess of 1000 K
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...

 (1340 °F
Fahrenheit
Fahrenheit is the temperature scale proposed in 1724 by, and named after, the German physicist Daniel Gabriel Fahrenheit . Within this scale, the freezing of water into ice is defined at 32 degrees, while the boiling point of water is defined to be 212 degrees...

). The planet's Bond albedo
Albedo
Albedo , or reflection coefficient, is the diffuse reflectivity or reflecting power of a surface. It is defined as the ratio of reflected radiation from the surface to incident radiation upon it...

 was found to be 0.31 ± 0.14.
In the infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 panel, the colors reflect what our eyes might see if we could retune them to the invisible, infrared portion of the light spectrum. The hot star is less bright in infrared light than in visible and appears fainter. The warm planet peaks in infrared light, so is shown brighter. Their hues represent relative differences in temperature. Because the star is hotter than the planet, and because hotter objects give off more blue light than red, the star is depicted in blue, and the planet, red.

The overall look of the planet is inspired by theoretical models of hot, gas giant planets. These "hot Jupiters" are similar to Jupiter in composition and mass, but are expected to look quite different at such high temperatures.

Radial velocity

The transit light-curve signature in the course of the TrES multi-site transiting planet survey, and confirmed the planetary nature of the companion via multicolor photometry and precise radial velocity
Radial velocity
Radial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity...

 measurements. With this, the planet has an orbital period similar to that of HD 209458 b
HD 209458 b
HD 209458 b is an extrasolar planet that orbits the Solar analog star HD 209458 in the constellation Pegasus, some 150 light-years from Earth's solar system, with evidence of water vapor....

, but about twice as long as those of the Optical Gravitational Lensing Experiment
Optical Gravitational Lensing Experiment
The Optical Gravitational Lensing Experiment or OGLE is a Polish astronomical project based at the University of Warsaw that is chiefly concerned with discovering dark matter using the microlensing technique. Since the project began in 1992, it has discovered several extrasolar planets as a side...

 (OGLE) transiting planets. Its mass is similar to that of HD 209458 b, but its radius is significantly smaller and fits the theoretical models without the need for an additional source of heat deep in the atmosphere, as has been invoked by some investigators for HD 209458 b.

Physical characteristics

Hubble might find water in TrES-1, and it would give a much more precise measurement of the planet's size, and even allow us to search for moons. A satellite is unlikely however, given the likely history and current orbital configuration for the planet, the research team concluded.

No moons have ever been detected beyond our solar system, but some researchers have considered that such satellites would be logical places for life to exist around giant gaseous worlds that otherwise could not be expected to support biology.

Models indicate that TrES-1 has undergone significant tidal heating in the past due to its eccentric orbit, but this does not appear to have inflated the planet's radius.

See also

  • Trans-Atlantic Exoplanet Survey
    Trans-Atlantic Exoplanet Survey
    The Trans-atlantic Exoplanet Survey or TrES, uses three 4-inch telescopes located at Lowell Observatory, Palomar Observatory, and the Canary Islands to locate exoplanets. It was made using the network of small, relatively inexpensive telescopes designed to look specifically for planets orbiting...

  • 51 Pegasi b
    51 Pegasi b
    51 Pegasi b , sometimes though unofficially named Bellerophon, is an extrasolar planet approximately 50 light-years away in the constellation of Pegasus...

  • HD 209458 b
    HD 209458 b
    HD 209458 b is an extrasolar planet that orbits the Solar analog star HD 209458 in the constellation Pegasus, some 150 light-years from Earth's solar system, with evidence of water vapor....

  • Hot Jupiter
    Hot Jupiter
    Hot Jupiters are a class of extrasolar planet whose mass is close to or exceeds that of Jupiter...

  • TrES-2b

External links

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