New Distance to the Orion Nebula

[newmoon]

From KenCroswell.com<br /><br />The Orion Nebula is probably at least 200 light-years closer to Earth than currently thought, says an astronomer in England. The new distance boosts the estimated age of the nebula's many stars by 70 percent.

 

[Smersh]

From Kencroswell.com:<br /><br /><b> "He exploited the rotation of G (yellow), K (orange), and M (red) stars in the Orion Nebula cluster to deduce that they are only about 1,300 light-years distant." </b><br /><br />Interesting. It seems strange to me that the original distance calculation could be out by such a large margin. I wonder if the estimated distances to other objects might also soon be amended using the above technique?<br /><br />Some odd "free-floating planets" were also discovered by my fellow Brits in the Orion Nebula back in 2000, so I guess we may have potential neighbours closer to us than originally believed ...<br /><br />http://news.bbc.co.uk/1/hi/sci/tech/686800.stm <div class="Discussion_UserSignature"> <h1 style="margin:0pt;font-size:12px">----------------------------------------------------- </h1><p><font color="#800000"><em>Lady Nancy Astor: "Winston, if you were my husband, I'd poison your tea."<br />Churchill: "Nancy, if you were my wife, I'd drink it."</em></font></p><p><font color="#0000ff"><strong>Website / forums </strong></font></p> </div>

 

[newmoon]

Well, for something as distant as the Orion Nebula, it's not that surprising for the distance to be off by this amount. I look forward to the day when we have accurate parallaxes to the prominent stars in Orion--especially Rigel and Betelgeuse. Hipparcos says their distances are 800 and 430 light-years, respectively, but I wouldn't be surprised if their actual distances are quite different from those numbers.

 

[Smersh]

<blockquote><font class="small">In reply to:</font><hr /><p>Finding a nice, bright Cepheid variable where the absolute brightness is related to the period of light intenisity change would do that. <p><hr /></p></p></blockquote><br /><br />I can see where you're coming from Steve, but does that mean that our distance estimates to other nebulae / clusters etc can only be considered to be reasonably accurate if they contain one or more cepheids do you think? <div class="Discussion_UserSignature"> <h1 style="margin:0pt;font-size:12px">----------------------------------------------------- </h1><p><font color="#800000"><em>Lady Nancy Astor: "Winston, if you were my husband, I'd poison your tea."<br />Churchill: "Nancy, if you were my wife, I'd drink it."</em></font></p><p><font color="#0000ff"><strong>Website / forums </strong></font></p> </div>

 

[newmoon]

Unfortunately, the Orion Nebula is so young that none of its stars has yet become a Cepheid. Someday, a spacecraft much better than Hipparcos will be able to measure parallaxes of some of the stars in the Orion Nebula cluster. That should give the definitive answer to the Orion Nebula's distance.