What Are the Largest Stars in Our Universe?

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SUMMARY

The largest star ever discovered is Epsilon Aurigae, with a diameter of 2,700 times that of the Sun. Other notable contenders include Mu Cephei, also known as the Garnet Star, with a diameter of 2,500 solar diameters, and Eta Carinae, which has a significant gas cloud that affects its apparent size. The discussion highlights the importance of distinguishing between a star's physical size and the size of associated gas clouds. Observational data and references were shared to support these claims, including links to detailed astrophysical resources.

PREREQUISITES
  • Understanding of stellar classification and measurement techniques
  • Familiarity with interferometry in astronomy
  • Knowledge of astrophysical terms such as supergiants and gas clouds
  • Basic principles of stellar evolution and lifecycle
NEXT STEPS
  • Research the measurement techniques used in stellar diameter determination, particularly interferometry
  • Explore the characteristics and classification of supergiant stars
  • Investigate the role of gas clouds in the apparent size of stars, focusing on Eta Carinae
  • Study the observational methods in astrophysics, including the use of telescopes for stellar observation
USEFUL FOR

Astronomy enthusiasts, astrophysicists, and students interested in stellar measurements and the characteristics of supergiant stars will benefit from this discussion.

juan avellaneda
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mira is a binary star! that's new for me
and this photos show the real surfasce of mira and betelgeuse, wow
if I am not wrong , Betelgeuses diameter was first meassured by interferometry
there are other supergiants waiting, like "Garnet" star, or R hydra. Whats the most giant star ever discovered??
thanks a lot for this new sights of the stars
 
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The biggest star ever discovered is epsilon Aurigae. It has a diameter of 2700 times the diameter of the sun

Saludos
 
Originally posted by meteor
The biggest star ever discovered is epsilon Aurigae. It has a diameter of 2700 times the diameter of the sun

Saludos
I have been looking around and keep finding that Eta Carina and/or Garnet Star are largest actual diameter. Do you have a site for me re: epsilon Aurigae ?
 
Originally posted by wolram
LABGUY
try , http://www.hposoft.com/Astro/PEP/EAURDATA.html
That gave light curves, and the home page mentioned the possibility of a giant "gas cloud" surrounding the two smaller stars accounting for the long period. I didn't see anything about the physical size of Epsilon Auriga itself except for its spectral class. ?? Anything more on the physical size of the star itself instead of associated (possible) gas clouds? If we count associated gas clouds with size, I think Eta Carina has them all beat.

From: http://groups.yahoo.com/group/astrospace-l/message/2005

"The "garnet star" has the largest known actual diameter:
http://features.LearningKingdom.com/fact/archive/1999/06/07.html "

Or maybe: http://www.astronomyinfo.pwp.blueyonder.co.uk/Big&Little.htm
" The star imaged below is possibly the largest star in the milky way galaxy. It is called Eta Carina in the southern constellation of Carina." But, http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0010271.html would support Epsilon Auriga.

No argument here, I just wonder if "they" know the largest individual star, now that my curiosity is peaked.
 
Last edited by a moderator:
Labguy,
see this page
http://www.aavso.org/vstar/vsots/1002.shtml
it says that the Garnet star (Mu Cephei) is the third largest star in the sky, and that the largest is Epsilon Aurigae

I have a notebook where I write curious facts about astrophysics and it my notes Epsilon Aurigae has a diameter of 2700 solar diameters. Mu Cephei has a diameter of 2500 solar diameters. It is also confirmed in this page
http://www.minorplanetsearch.com/hap_ic1396.html
From the page you gave
http://www.astronomyinfo.pwp.blueyonder.co.uk/Big&Little.htm
it says that eta carinae has a diameter of 100 solar diameters, but
it's surrounded by two lobes of gas that makes it to seem bigger.
I wouldn't count those lobes as forming part of the star, just are gases that are been expelled in the final stages of eta carinae, just before it goes supernova.
It's just like when a star that reaches the end of the main sequence expells all these gases when it reaches the phase of planetary nebula. I don't think that we should count these gases like forming part of the star
I remember to have observed Epsilon Aurigae with my telescope. I didn't knew then that it was the biggest star, but when I read it, I was happy to have observed it.
Perhaps it's time to return to do some observational astronomy. It has been more than 3 months since I don't touch my telescope.I Have been lately very much busy studying theoretical aspects of cosmology
 
Last edited by a moderator:
This reference gives absolute radii of several thousand stars, many determined with an accuracy of ~<1%. Apart from an item which seems obviously erroneous (RS Vul), the largest diameter in the list is "EPS AUR", at 2700 sol. #2 is "VV CEP" with diameter listed as 2000, 1940, and 1230 (three different observations). However, note that \epsilon Aur has other entries: 1270, 1000, 716, ...

Mira (o Cet) has lots of entries, one of which is 230.

[Edit: fixed typo, cleared up an ambiguity]
 
Last edited:
Meteor & Nerid;
Thanks for the links, that's what I needed. I didn't "want" to count associated gas as with Eta Carina. I have dabbled with stellar evolution for years, it just never dawned on me to wonder which star(s) were the largest measured to-date.
 

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