APOD: At the Heart of Orion (2017 Mar 12)

Comments and questions about the APOD on the main view screen.
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Chris Peterson
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Re: APOD: At the Heart of Orion (2017 Mar 12)

Postby Chris Peterson » Wed Mar 15, 2017 12:25 am

douglas wrote:Dr. Ladislav Subr of Charles University in Prague

November 1, 2012 in the Astrophysical Journal

.. We further show that the putative massive black hole is likely to be a member of a binary system with ≈70% probability. [heh, really? :) ] In such a case, it could be detected either due to short periods of enhanced accretion of stellar winds from the secondary star during pericentre passages, or through a measurement of the motion of the secondary whose velocity would exceed 10 km s–1 along the whole orbit.

Not necessarily. Most black hole/star binaries don't have any material transport between the pair. And you're assuming a measurement that may simply not have been made.

I'm really not sure what your problem is. This is solid science. It has been observed that the Trapezium stars have unusually high velocities, which sets up the question, why? One hypothesis is the presence of an intermediate mass black hole, and the work described in the paper demonstrates a plausible mechanism for the formation of such a black hole, and also demonstrates that it could explain the observed star motion. It further proposes observational tests that could confirm or refute the existence of such an object.

The methodology is sound and the work has survived peer review. Second guessing it (especially with unsupportable assumptions about material falling into the black hole, or false comparisons to supermassive black holes) is pretty pointless, and risks going outside the rules for this forum.
Chris

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BDanielMayfield
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Re: APOD: At the Heart of Orion (2017 Mar 12)

Postby BDanielMayfield » Wed Mar 15, 2017 3:43 am

This has been and is a most interesting debate. As I brought up before, the proper motion data from the Gaia mission could go far to resolve this BH or no BH in Orion issue. If, that is, the Trapezium stars are within the brightness range of Gaia. Are they?
And, if they are, is there any early word about this most interesting patch of space?

Bruce
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Chris Peterson
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Re: APOD: At the Heart of Orion (2017 Mar 12)

Postby Chris Peterson » Wed Mar 15, 2017 3:59 am

BDanielMayfield wrote:This has been and is a most interesting debate. As I brought up before, the proper motion data from the Gaia mission could go far to resolve this BH or no BH in Orion issue. If, that is, the Trapezium stars are within the brightness range of Gaia. Are they?
And, if they are, is there any early word about this most interesting patch of space?

AFAIK, Gaia's normal measurement system can deal with stars as bright as magnitude 3, and the stars of the Trapezium are around mag 5, so yes, they should be measurable. Of course, we're talking about measuring motion, so that involves multiple measurements made over some period of time. You could look in the Gaia catalog released last year to see if those stars are cataloged, and if they've measured any proper motions.
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