Alcor

Alcor can refer to:

Mizar and Alcor

Mizar and Alcor form a naked eye double star in the handle of the Big Dipper asterism in the constellation Ursa Major. Mizar is itself a quadruple system and Alcor is a binary, the pair together forming a sextuple system.

Description

Mizar (Zeta Ursae Majoris, Zeta UMa, ζ Ursae Majoris, ζ UMa, known as Arundhati-Vasishtha in Sanskrit (अरुन्धती-वशिष्ठ) and in Arabic as "المئزر" (mīzar, meaning a waistband or girdle) is a quadruple system, a visual double with a separation of 14.4 arcseconds, each of which is a spectroscopic binary, in the constellation Ursa Major and is the second star from the end of the Big Dipper's handle. Its apparent magnitude is 2.23 and its spectral class is A2V.

With normal eyesight one can make out a faint companion about 12 minutes of arc from Mizar, named Alcor or 80 Ursae Majoris. Alcor is of magnitude 3.99 and spectral class A5V. It has a faint red dwarf companion separated by 1".

Mizar and Alcor's proper motions show they move together (they are both members of the Ursa Major Moving Group), but it has yet to be demonstrated conclusively that they are gravitationally bound. Recent studies indicate that the Alcor binary and Mizar quadruple are somewhat closer together than previously thought: approximately 74,000 ± 39,000 astronomical units or 0.5–1.5 light years.

ALCOR

ALCOR is an early computer language definition created by the ALCOR Group, a consortium of universities, research institutions and manufacturers in Europe and the USA which was founded in 1959 and which had 60 members in 1966. The group had the aim of a common compiler specification for a subset of ALGOL 60 after the ALGOL meeting in Copenhagen in 1958. ALCOR is an acronym, from ALGOL Converter.

In addition, the naming of Alcor is an astronomical reference. Algol is named, in addition to its programming application, for the star Algol; In this way, Alcor is also named in astronomical reference for the star Alcor.

In Europe, a high level machine architecture for ALGOL 60 was devised which was emulated on various real computers, among them the Siemens 2002 and the IBM 7090. An ALGOL manual was published which provided a detailed introduction of all features of the language with many program snippets, and four appendixes: