44 Boötis, also known as i Boötis, is a

triple star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. It may sometimes be used to refer to a single star. A large group of stars bound by gravitation is generally called a ''st ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Boötes Boötes ( ) is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from , which comes from 'herder, herdsman' or 'plowman' (literally, 'o ...

. It is approximately 41.6

light years A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astro ...

from Earth. 44 Boötis can be resolved into two stars, of 5th and 6th magnitudes respectively. They were separated by when the pair were confirmed in 1819, but were only by 2020 as the two orbit every 210 years. The primary component, 44 Boötis A, also named Quadrans, is a yellow-white

G-type main sequence star A G-type main-sequence star (spectral type: G-V), also often, and imprecisely, called a yellow dwarf, or G star, is a main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.9 to 1.1 solar masses and an effective tempe ...

with a mean

apparent magnitude Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...

of +4.83. The companion component, 44 Boötis B, is a W Ursae Majoris variable

spectroscopic binary A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

. The variability of this star system was discovered by English astronomer

William Herschel Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover ...

. The brightness of the

eclipsing binary A binary star or binary star system is a Star system, system of two stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved ...

varies from magnitude +5.8 to +6.40 with a period of 6.43 hours. The two eclipsing components of the system are close enough to allow their stellar envelopes to overlap, or at least nearly so. In 1948, flare behavior was measured from this system based on data from O. J. Eggen. 44 Boötis appears to have an

infrared excess An infrared excess is a measurement of an astronomical source, typically a star, that in their spectral energy distribution has a greater measured infrared flux than expected by assuming the star is a blackbody radiator. Infrared excesses are of ...

, implying the existence of a dust disk that absorbs visible light and re-emits it as

infrared light Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those o ...

. The dust would have a blackbody temperature of about 23 K, situated up to 182 au from the parent star. This star was a member of the obsolete constellation Quadrans Muralis. The

IAU Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

approved the name Quadrans for component A on 17 February 2025, after the obsolete constellation, and it is now so entered in the IAU Catalog of Star Names.

References

External links

HR 5618

Image 44 Boötis

CCDM J15038+4739
{{DEFAULTSORT:44 Bootis Boötes Bootis, i Bootis, 44 133640 087379 Spectroscopic binaries Triple star systems W Ursae Majoris variables G-type main-sequence stars Bootis, 44 5618 0575 BD+48 2259 K-type main-sequence stars

Quadrans The ''quadrans'' () or ''teruncius'' () was a low-value Roman bronze coin worth one quarter of an '' as''. The ''quadrans'' was issued from the beginning of cast bronze coins during the Roman Republic, showing three pellets representing thre ...