skyscript.co.uk
   

home articles forum events
glossary horary quiz consultations links more

Read this before using the forum
Register
FAQ
Search
View memberlist
View/edit your user profile
Log in to check your private messages
Log in
Recent additions:
The Life & Work of Vettius Valens
by Deborah Houlding
Can assassinations be prevented? by Elsbeth Ebertin
translated by Jenn Zahrt PhD
A Guide to Interpreting The Great American Eclipse
by Wade Caves
The Astrology of Depression
by Judith Hill
Understanding the zodiac: and why there really ARE 12 signs of the zodiac, not 13
by Deborah Houlding

Skyscript Astrology Forum

Algol

 
Post new topic   Reply to topic    Forum Index -> Traditional (& Ancient) Techniques
View previous topic :: View next topic  
Author Message
Ouranos



Joined: 28 Mar 2020
Posts: 570

Posted: Tue Aug 17, 2021 12:34 am    Post subject: Algol Reply with quote



The star Algol takes its name from an Arabic word meaning “the Demon’s Head.”
In 1900, it was at 24 Tau 46 ---- In 2000 at 26 Tau 10
Algol isn’t any scarier that any other star. But it’s associated in skylore with a greek mythical scary monster – the Gorgon, Medusa – who had snakes instead of hair. It’s said that she was so horrifying in appearance that the sight of her would turn an onlooker to stone.
In the mythology of the skies, Perseus – a great hero often depicted mounted on Pegasus the Flying Horse – used Medusa’s head to his own advantage – to turn Cetus the Sea-monster into stone. Perhaps the ancients associated this star’s variable brightness with the evil, winking eye of the Medusa.
The Chinese gave it the gruesome title Tseih She, the Piled-up Corpses.



Steady observation of Algol reveals a surprise. As regular as clockwork, every 2.867... days, the brightness of the star plummets from mid second magnitude (2.1) to the dim end of third (3.4, just 30 percent of normal), the whole event (including recovery) taking only a few hours.

It is very easy to note these variations by comparing Algol to other nearby and non-variable stars, such as:
- Almach (Andromeda gamma) (magnitude 2.1).
- Alpha Triangle (magnitude 3.4).
To Locate Algol. Head north and locate the constellation Cassiopeia (Shaped '' W '') It will be easy for you to find then Almach, the triangle ... Then Algol ...



The cause of the sudden drop is a stellar eclipse. Algol is a close double star. The companion to the visually observed star is a much dimmer yellow-orange class K giant star.. For simplicity, let's call it the "K giant.") The B star, at 2.9 solar radii, is smaller than the K giant (3.5 solar). Each orbit, when the dimmer, larger K star passes in front of the brighter B star, we see a deep eclipse. The eclipse is only partial, some of the light of the principal component still shining brightly through. Between the deep "primary" eclipses is a smaller dip when the bright star passes partially in front of the dim one.

Algol is almost circumpolar, meaning it almost never sets below the horizon at latitudes around 50 degrees. However, in the early evening, it is in winter that it peaks at the zenith.

Algol is equally famed for the "Algol paradox." The two stars are so close together, separated by only five percent the distance between the Earth and the Sun, that the brighter smaller star produces tides in the larger one. Matter then flows in from the large one (at a rate of around two hundred- millionths of a solar mass per year) to the small bright one, the effect directly observed through the stellar spectrum as the K giant is being stripped nearly to its core. A third member of the system, Algol C, a class A or F star of 1.8 solar masses, orbits about 3 Astronomical Units away with a period around the inner pair of 1.86 years. The system is a source of X-rays, though whether they come from a corona around one of the stars or from the flow of matter hitting the B star is uncertain.

3000 years ago, Algol was eclipsed more frequently by the star that revolves around it. This is what Finnish scientists at the University of Helsinki discovered by examining calendars from ancient Egypt.
The Egyptian people, at the time of the pharaohs, had already noticed that the brightness of the star, visible to the naked eye, varied according to a precise cycle. This cycle has been recorded for centuries in calendars intended for prediction and religion. It was measured for the first time by John Goodricke, a British amateur astronomer in 1783.
Question: At birth, when Algol is being eclipsed, does it have an influence different than the day when it is not eclipsed? ... Since the Egyptians kept a calendar of this phenomenon.

Winking? Yes. Algol is a known variable star, which waxes and wanes in brightness every second day. Please relax. Here on Earth we only get eclipses every 6 months or so.


Sources:
http://stars.astro.illinois.edu/sow/algol.html
http://olravet.fr/Algol/algol.php
https://www.cieletespace.fr/actualites/algol-l-etoile-qui-ralentit
https://fr.wikipedia.org/wiki/Algol_(%C3%A9toile)
https://earthsky.org/brightest-stars/algol-the-demon-star/
_________________
Blessings!
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Forum Index -> Traditional (& Ancient) Techniques All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
. Powered by phpBB © 2001, 2005 phpBB Group

       
Contact Deborah Houlding  | terms and conditions  
All rights on all text and images reserved. Reproduction by any means is not permitted without the express
agreement of Deborah Houlding or in the case of articles by guest astrologers, the copyright owner indictated