Andy's Wiki
Exoplanetary Scratchpad

[SysBP Img]

Contains one of the first four discovered Hot Jupiters, which was one of the largest, hottest, closest in (P = 3.3d, a = 0.05) of the earlier discovered ones and the closest known at the time and is today one of the brightest planets known. It was immediately recognized to have tidally locked its star's rotation period. The star (also known as HR 5185) is nearby (50 ly), 1.5 times as massive as the sun. The planet does not transit its star, but is one of the brightest planets known. Several attempts to detect light were declared, but then refuted. In one such attempt by British astronomers, it was nicknamed the "Millenium Planet", and light was thought to have been detected (thought to be a first) by subtracting its star's light, giving an inclination of 29deg, mass of 8 MJ, and size of 1.8 RJ, and blue-green color. NASA's Spitzers later was thought to have detected it (again, a believed first, considering visually detected ones were planetary "candidates"). It was finally detected later by observing CO lines produced by reflected light through its atmosphere, yielding a mass of 6 MJ and inclination of 44F. Water was later also detected in its atmosphere in the near infra-red, the first for any non-transiting exo-planet. The temperature was unexpectedly found to be cooler at the upper levels, unlike many other hot Jupiters (strong ultraviolet radiation are thought to destroy the compounds responsible for creating thermal inversions in this case). The star was the first to have its magnetosphere detected (which envelopes the planet) and also the first known to magnetically flip like the Sun (flips once every Earth year, vs the Sun's 11 years). One of the first 20 exoplanet systems allowed to be given common names by the IAU, but the only one whose chosen name was rejected because it did not conform to IAU's naming standards.

My Thoughts[]

I wonder if being cooler in the upper atmosphere is a trait of very hot super Jupiters. The stellar wind is thought to have blown away the chemicals responsible for thermal inversion in this case. The star's extra magnetic activity may be due to the fact that there's this very large planet orbiting very close to it. So there's this weird kind of feedback between the planet and star. I also hope that they're able to use the techniques used to detect its atmosphere and inclination on other planets soon. I haven't heard of too many instances yet.


In the herdsman constellation. Discovered by Californians.

  • Ushiwaka - a famous warrior in Japan whose name contains the word "cow" in it. The planet has an assistant who has an anecdote with his shin, which is where the star is located in the constellation.
  • Synra - a Japanese word meaning all things which takes into account that the constellation was thought to be a giant with the universe on his shoulders.

Tau Bootes System Web Pages[]

Tau Bootes System In the News[]

Planet b Discovered (1997)[]

Light Captured For First Time for Any Exoplanet (1999)[]

Light Detection Disproven, New Limits (2003)[]

Spitzer Directly Detects Planet's Light (Mar 2005)[]

Stars Rotation Locked With Planet (May 2005)[]

Tau Bootes is the first star found to be tidally locked with one of its planets.

Star's Magnetosphere Probed (2006)[]

Planet b is the first planet found to be inside of its star's magnetic field and interacting with it.

Planet Failed to Be Detected Via Polarized Light (2008)[]

Atmosphere Probed without Transit, Orbit, Mass Refined (Jun 2012)[]

Magnetic Cycle Detected (2013)[]

Water Detected in the Near Infra-Red (2014)[]

Look Back on MOST's Accomplishments[]

One of the Top 20 Exoplanetary Systems First Up For Naming (May 2015)[]

See Also[]