2.88). But opting out of some of these cookies may have an effect on your browsing experience. This week, skywatchers will have the chance to catch a winking "demon star" in the night sky. Algol came within 9.8 light years of the Sun 7.3 million years ago. Algol requires only 5 hours to fade from maximum to minimum. Perhaps this is why few other astronomers paid much attention to Montanari's discovery. Later that year, the Royal Society awarded Goodricke the Copley Medal for his discovery of periodicity of Algol. In the Tetrabiblos, the 2nd-century astrological text of the Alexandrian astronomer Ptolemy, Algol is referred to as "the Gorgon of Perseus" and associated with death by decapitation: a theme which mirrors the myth of the hero Perseus's victory over the snake-haired Gorgon Medusa. Necessary cookies are absolutely essential for the website to function properly. It was one of the 15 Behenian stars, believed to be a source of astrological power and used in various rituals. The Alexandrian astronomer Claudius Ptolemy called the star “the Gorgon of Perseus” in his Tetrabiblos, a text on astrology written in the 2nd century CE. Algol gives its name to its class of eclipsing variable, known as Algol variables. It is mandatory to procure user consent prior to running these cookies on your website. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. (all times approximate). Algol has a long and venerable history. Algol definition, a star of the second magnitude in the constellation Perseus: the first known and most famous eclipsing binary star. A third component, much fainter than the other two stars, was also detected in the system. [48] Astrologically,[clarification needed] Algol is considered one of the unluckiest stars in the sky,[42] and was listed as one of the 15 Behenian stars. The star is also known as Gorgona, Gorgonea Prima, Demon Star and El Ghoul. Image: Dr. Fabien Baron, Dept. "Demon Star" Algol Of Perseus Constellation Visible In Night Sky This Week. A study published in 1998 found a strong correlation between the X-ray activity and evolutionary stage in components of Algol-type binary systems. For the programming languages, see, An eclipsing variable star in the constellation Perseus. It is your right and your responsibility. Image: Wikimedia Commons/Philip D. Hall (CC BY-SA 4.0). Animation done on Mathematica by Simon Tyran (Yukterez, Vienna, 2.2.2016). Medieval astrologers counted it among the 15 Behenian fixed stars, which were believed to be a source of special influence on one or more planets and considered useful for magical applications. Over time, the more massive and evolved star sheds much of its material, which is accreted by the companion, which then gradually becomes more massive. 2.21) in Vela. -1.47) is today. [42] Hipparchus and Pliny made this a separate, though connected, constellation. The star has been known since ancient times. However, as the companions in these systems could not be resolved in a telescope, the systems were identified as spectroscopic binaries. This website uses cookies to personalise content and ads, and to analyse user traffic. A 2015 study confirmed that the descriptions of the actions of Horus were consistent with the periodicity of the star and that the Cairo Calendar was the oldest known historical document with a record of the discovery of a variable star. In the case of Beta Persei, the less massive star – the secondary component – has already evolved into a subgiant, while the considerably more massive primary component is still on the main sequence. It is a triple star system composed of Beta Persei Aa1, a B-class main sequence star, Beta Persei Aa2, an orange subgiant, and Beta Persei Ab, a dimmer A-class star. Declination: +40°57’20.3280’’ This material may not be published, broadcast, rewritten or redistributed. Beta Persei Aa2 is less massive than the Sun, with 0.70 solar masses, but has expanded to a size of 3.48 solar radii as it has evolved away from the main sequence. The images vary in quality, but the best have a resolution of 0.5 milliarcseconds, or approximately 200 times better than the Hubble Space Telescope. This category only includes cookies that ensures basic functionalities and security features of the website. The light curve revealed the second minimum and the reflection effect between the two stars. Right ascension: 03h 08m 10.13245s [42] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[43] to catalog and standardize proper names for stars. Algol, Gorgonea Secunda, Gorgonea Tertia and Gorgonea Quarta, image: Wikisky, In the 17th, 18th, and 19th centuries, the four stars appeared on several maps as a sub-constellation called Caput Medusae, also meaning “the head of Medusa.”. The ancients mistrusted Algol’s blinking and inexplicable 8 hour disappearances. This website uses cookies to personalise content and ads, and to analyse user traffic. It formally applies only to the component Beta Persei Aa1. Tidal distortions also result in “gravity darkening” effects, whereby in a significant number of images of Algol B, the edge or “limb” of the image is actually brighter than the center. Let us know if you have suggestions to improve this article (requires login). Its apparent visual magnitude changes over the range of 2.1 to 3.4 with a period of 2.87 days. Algol and Almach can be used to find several bright deep sky objects that lie in the region between the two stars. It lies at a distance of 90 light years from Earth. The bright stars of Cassiopeia can be used to star-hop to Mirfak, the brightest star in Perseusand the central star of the Alpha Persei Cluster, and then to Algol. The name probably derives from an Arabic phrase meaning “demon,” or “mischief-maker,” and the Arabs may have been aware of the star’s variability even before the invention of the telescope. Caput Algol same as Algol: 26: 26 Taurus 10 : Algol in Medusa's head (a Royal Behenian Star) (Perseus) Magical Correspondences: 27: 28 Taurus 58: Atlas Magical Correspondences The father of the Hyades and Pleiades: 28: 28 Taurus 59 Anthony Shepherd, D. D. F. R. S. and Plumian Professor at Cambridge", "John Goodricke, The Discovery of the Occultating Variable Stars", "The 2001 US Naval Observatory Double Star CD-ROM. The secondary eclipses occur when the primary component eclipses the fainter star, but these are very shallow and, unlike primary eclipses, which can be seen by the unaided eye, they can only be detected photoelectrically. He found that the companion gave off more light than the Sun and was much brighter on the side facing the primary component. Names and designations: Algol, Demon Star, Gorgona, Gorgonea Prima, El Ghoul, Beta Persei (β Persei, β Per), 26 Persei, HD 19356, HR 936, BD+40°673, SAO 38592, FK5 111, PPM 46127, GC 3733, HIP 14576, Spectral class: B8V [22] Thus Algol became one of the first known spectroscopic binaries. Age: 570 million years, Spectral class: K0IV Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. At its dimmest, at magnitude +3.4, it is distinctly fainter than the nearby star Epsilon Persei. This animation was assembled from 55 images of the CHARA interferometer in the near-infrared H-band, sorted according to orbital phase. Because the total mass of the Algol system is about 5.8 solar masses, at the closest approach this might have given enough gravity to perturb the Oort cloud of the Solar System somewhat and hence increase the number of comets entering the inner Solar System. These cookies do not store any personal information. Tidal distortions also result in “gravity darkening” effects, whereby in a significant number of images of Algol B, the edge or “limb” of the image is actually brighter than the center. While that doesn’t sound like much, this can accumulate over a span of a year or so, causing the time of the predicted minimums to come some minutes early or late. Its apparent visual magnitude changes over the range of 2.1 to 3.4 with a period of 2.87 days.
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