A star response from a listener

by Molly Bentley on November 15, 2010

A listener responds to MIT’s Josh Winn’s interview in the recent “Off to the Traces” episode about measuring distances to stars. In the exchange below he points out another method of accurately measuring distances to stars that are even farther way than 1000 light years.

“I think Josh Winn’s statement ‘we can measure the distances to stars out to about 1000 light years’ is incorrect. If he was referring specifically to the parallax method, then I agree. However, if he is referring to measuring distances to stars in general, I think he is incorrect.

However, modeling eclipsing binary stars allows for a direct measurement of the distance to these systems. For example, a paper I am currently working on is measuring the distance to an eclipsing binary star within the Rosette Nebula, which is about 1.3 Kpc away, about 4 times further away than Josh’s claim of ‘1000 light years.’

Sorry to nitpick but I do feel this is significant!”

-Victor Garcia Fisk-Vanderbilt Bridge Program

And Josh responds:

“Your astute listener is correct: the upper limit of about 1000 light years refers only to the parallax method. There are many other (less reliable)methods for reckoning distances to more distant stars.”

  • Josh Winn Astrophysicist, MIT

{ 1 comment… read it below or add one }

avatar Stpehen January 19, 2011 at 2:01 pm

And, on top of that, the 1,000 light year distance is about as far as HIPPARCOS saw by 1993. The Hershel space telescope is about 12 times the diameter of HIPPARCOS. So an astrometry mission today could do at least 12 times better, using the same techniques. We’re not up against physics here.

HIPPARCOS achieved 2000 microarcsecond angular resolving precision. VLBI, very long baseline interferometry – in radio, has achieved 15 microarcseconds. That’s over 100 times better, and from the ground.

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