Thuban formed from an interstellar medium of dust and gas. Gravity pulled the swirling dust and gas together and formed the now dethroned pole star. Based upon it metallicity, the interstellar medium from which Thuban formed, was somewhat metal-poor.
However, it has ceased hydrogen fusion in its core, and it is no longer in the main-sequence. The primary component star is both more massive and several times bigger than our Sun.
Thuban has 2. Based upon its radius, Thuban should be around six times, or more, bigger than our Sun. Thuban is a white giant star of spectral class A0III , indicating similarities to Vega in temperature and spectrum, but more luminous and massive.
It has ceased hydrogen fusion in its core and started to expand. It has an apparent magnitude of 3. Thuban is times brighter than our Sun and has average surface temperatures of around 10, K, or 1.
Not much is known about the companion, though it is speculated that it is a main-sequence star slightly cooler than Thuban, and possibly of spectral type A2.
The two stars orbit each other once every The two components are separated from one another by about 0. This system is an eclipsing binary star system. These eclipses last for only six hours. Thuban was closest to the pole in BCE, coming closest to the north celestial pole out of all the other pole stars. This site uses cookies to assist with navigation, analyse your use of our services, collect data for ads personalisation and provide content from third parties. By using our site, you acknowledge that you have read and understand our Privacy Policy and Terms of Use.
January 7, The star Alpha Draconis circled , also known as Thuban, has long been known to be a binary system. Explore further. Provided by NASA. Citation : Surprise! This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Synthesizing nanomaterials from nature's blueprints 11 hours ago.
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Nov 10, The red arrow shows the motion of Thuban during the next years Proper Motion RA Proper Motion Dec 0. Color Index B-V H-R diagram showing the position of Thuban. Flamsteed designation 11 Draconis. Henry Draper Catalogue HD Hipparcos Catalogue HIP
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