* Atlas ( star ), a triple star system in the Pleiades cluster

In the case of an observer on Earth, the direction of a star's velocity varies during the year as Earth revolves around the Sun ( or strictly speaking, the barycenter of the solar system ), and this in turn causes the apparent position of the star to vary.

( It is sometimes listed as 15th brightest, if the two brighter components of the Capella quadruple star system are counted as one star.

* Binary star, a star system with two stars in it

Parallels to the earliest Babylonian ( Sumerian ) star catalogues suggest that the ancient Chinese system did not arise independently from that of the Ancient Near East.

The game can be won by destroying all other civilizations, reaching the end of the modern era with the highest score, or by winning the space race by reaching the star system of Alpha Centauri.

Alpha Centauri is not actually a sequel to Civilization, despite beginning with the same event that ends Civilization and Civilization II: a manned spacecraft from Earth arrives in the Alpha Centauri star system.

AA Ceti is a triple star system ; the brightest member has a magnitude of 6. 2.

Alpha Centauri is a triple star system that contains Proxima Centauri, the nearest star to the Sun.

Graham became a star under Brown's system, leading all passers in each of the AAFC's seasons and racking up 10, 085 passing yards.

The idea is that places where reactions occur – even an incredible environment as a star – presents a possible medium for some chain of events that could produce a system able to replicate.

Such a " sphere " would be a system of orbiting solar power satellites meant to completely encompass a star and capture most or all of its energy output.

Kepler-16 contains the first discovered planet that orbits around a binary star system.

For example, if there is a triple star system in which two stars orbit each other closely while a third star is in a more distant orbit, the two closely orbiting stars would be considered a component with two subcomponents.

For example, the three members of the Alpha Centauri triple star system are conventionally referred to as Alpha Centauri A, B and C while the formal standard would give their designations as Alpha Centauri Aa, Ab and B respectively.

If several planets in the same system are discovered at the same time, the closest one to the star gets the next letter, followed by the other planets in order of orbital size.

For instance, in the 55 Cancri system the first planet – 55 Cancri b – was discovered in 1996 ; two additional farther planets were simultaneously discovered in 2002 with the nearest to the star being named 55 Cancri c and the other 55 Cancri d ; a fourth planet was claimed ( its existence was later disputed ) in 2004 and named 55 Cancri e despite lying closer to the star than 55 Cancri b ; and the most recently discovered planet, in 2007, was named 55 Cancri f despite lying between 55 Cancri c and 55 Cancri d. As of April 2012 the highest letter in use is " j ", for the unconfirmed planet HD 10180 j ( HD 10180 h is the confirmed planet with the highest letter ).

If a planet orbits one member of a binary star system, then an uppercase letter for the star will be followed by a lowercase letter for the planet.

He made the first measurement of stellar parallax: 0. 3 arcsec for the binary star 61 Cygni.

61 Cygni is a binary star divisible in large binoculars or a small amateur telescope.

61 Cygni is significant because Friedrich Wilhelm Bessel determined its parallax in 1838, the first star to have a known parallax.

In 1838 Bessel won the race, announcing that 61 Cygni had a parallax of 0. 314 arcseconds ; which, given the diameter of the Earth's orbit, indicated that the star is 10. 4 ly away.

The first direct measurement of the distance to a star ( 61 Cygni at 11. 4 light-years ) was made in 1838 by Friedrich Bessel using the parallax technique.

But Friedrich Bessel was skeptical about Struve's data, and, when Bessel published a parallax of 0. 314 ″ for the star system 61 Cygni, Struve revised his value for Vega's parallax to nearly double the original estimate.

* 1838 – Friedrich Wilhelm Bessel measures the parallax of the star 61 Cygni, refuting one of the oldest arguments against heliocentrism.

Ashrita Furman set the Guinness World Record for number of star jumps ( jumping jacks ) in one minute at 61, on May 17, 2008.

* 61 Gm — Diameter of Aldebaran, an orange giant star ( large star on right )

The first successful measurement of stellar parallax was made by Friedrich Bessel in 1838 for the star 61 Cygni using a Fraunhofer heliometer at Königsberg Observatory.

The first successful measurements of stellar parallax were made by Friedrich Bessel in 1838 for the star 61 Cygni using a heliometer.

He was also the first to measure the parallax of Vega, although Friedrich Bessel had been the first to measure the parallax of a star ( 61 Cygni ).

LSI + 61 ° 303 is a variable radio source characterized by periodic, non-thermal radio outbursts with a period of 26. 496 d. The 26. 5 d period has been attributed to the eccentric orbital motion of a compact object, probably a neutron star, around a rapidly rotating B0 Ve star, with a T < sub > eff </ sub > ~ 26, 000 K and luminosity of 10 < sup > 31 </ sup > watts ( 10 < sup > 38 </ sup > erg s < sup >− 1 </ sup >).

Clement assumed Mesklin's orbit around its star ( which he decided would be 61 Cygni A ) took 1, 800 Earth-days, and was highly elliptical: at its closest point the average temperature would be − 50 ° C, while at the furthest its average temperature would be − 180 ° C.

Bessel proved that the parallax of a star was greater than zero by measuring the parallax of 0. 314 arcseconds of a star named 61 Cygni.

With the object of testing the capabilities of the method, he took for his first essay the well-known star 61 Cygni, and his results agreed so well with those previously attained that he undertook the systematic measurement of the parallaxes of second-magnitude stars, and published the outcome in the third and fourth volumes of the Publications of the Oxford University Observatory.

In regards to the stars, Tycho also believed that if the Earth orbited the Sun annually there should be an observable stellar parallax over any period of six months, during which the angular orientation of a given star would change thanks to Earth's changing position ( this parallax does exist, but is so small it was not detected until 1838, when Friedrich Bessel discovered a parallax of 0. 314 arcseconds of the star 61 Cygni in 1838 ).

The Kzin home world is the third planet orbiting the star 61 Ursae Majoris.

It orbits the star 61 Ursae Majoris, has stronger surface gravity and both a longer day and year than Earth.

* Friedrich Wilhelm Bessel makes the first accurate measurement of distance to a star, 61 Cygni, using parallax.

Alpha Cygni, called Deneb, is the brightest star in Cygnus.

Albireo, designated Beta Cygni, is a celebrated binary star among amateur astronomers for its contrasting hues.

Gamma Cygni, traditionally named Sadr, is a yellow-tinged supergiant star of magnitude 2. 2, 1500 light-years away.

Delta Cygni is another bright binary star in Cygnus, 171 light-years with a period of 800 years.

The fifth star in Cygnus above magnitude 3 is Gienah, designated Epsilon Cygni.

Mu Cygni is a binary star with an optical tertiary component.

Omicron Cygni is a contrasting double star similar to the brighter Albireo.

The primary, 31 Cygni, is an orange-hued star of magnitude 3. 8, 1400 light-years from Earth.

The secondary, 30 Cygni, is a blue-green hued star of magnitude 4. 8, 720 light-years from Earth.

31 Cygni itself is a binary star ; the tertiary component is a blue star of magnitude 7. 0.

Psi Cygni is a binary star divisible in small amateur telescopes, with two white components.

16 Cygni is a binary star 70 light-years from Earth.

Chi Cygni is a red giant and the second-brightest Mira variable star at its maximum.

W Cygni is a semi-regular variable red giant star, 618 light-years from Earth.

Serkowski measured CP of for the red supergiant NML Cygni and in the long period variable M star VY Canis Majoris in the H band, ascribing the CP to multiple scattering in circumstellar envelopes.

Albireo ( β Cyg, β Cygni, Beta Cyg, Beta Cygni ) is the fifth brightest star in the constellation Cygnus.