Newfound black hole is the closest one to Earth we've ever found

[smp]

From Space.com:
"A newfound black hole may be the closest black hole to Earth, and you can spot its cosmic home in the night sky without a telescope.

The black hole, which is lurking 1,000 light-years from Earth in the southern constellation of Telescopium, belongs to a system with two companion stars that are bright enough to observe with the naked eye. But you won't be able to see the black hole itself; the massive object has such a strong gravitational pull that nothing — not even light — can escape it."

https://www.space.com/closest-black-hol ... overy.html

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[KingClinton]

I am perfectly situated to have a gander at this. I do realize I will not see the BH itself but knowing it is there is enough for me.
Thanks for the link to the article.

[AntennaGuy]

Awesome. And that's plenty close enough, thank you. Those things are dangerous.

[GCoyote]

Now that is intriguing. A visible system, a 40 day orbit. What measurements could a backyard astronomer make and would that data be enough to deduce the existence of the black hole?

[KathyNS]

A 40-day orbit is likely too small to detect the star's orbital motion directly with amateur equipment. You might be able to tell spectroscopically, though I suspect that suitable equipment is out of the reach of amateurs. Might be fun to try, though.

[KingClinton]

Now that is intriguing. A visible system, a 40 day orbit. What measurements could a backyard astronomer make and would that data be enough to deduce the existence of the black hole?

Taking a quick look at Skysafari, it is listed as a variable star, not a double, it shows HD6189 or QV telescopii as the bright star that is naked eye visible(provided you are under dark skies) at 5th magnitude.
But what designations do the other stars in the system have?
If I intend looking in the scope will I see the double or are they too close together?
Some articles make mention of a triple system?
Anyone with additional information?

Screen shot from Skysafari pro6.

[KingClinton]

Setting Skysafari to show down to 17th magnitude, I get this.
All the surrounding stars are 14th magnitude with a very zoomed in view.

[GCoyote]

A 40-day orbit is likely too small to detect the star's orbital motion directly with amateur equipment. You might be able to tell spectroscopically, though I suspect that suitable equipment is out of the reach of amateurs. Might be fun to try, though.

Agreed, I would not expect to see parallax at that distance even with great equipment. But a 40 day orbit must indicate a pretty high orbital velocity so I wondered if there might not be a noticeable shift in the spectrum.

Have to do a bit more reading. The system may have other properties we could explore.

[KingClinton]

Did some digging and they are to close together for any of our amateur scopes.
The inner star appears to be a B3 III.
Link to the paper is here: https://www.aanda.org/articles/aa/full_ ... 20-20.html

[notFritzArgelander]

A 40-day orbit is likely too small to detect the star's orbital motion directly with amateur equipment. You might be able to tell spectroscopically, though I suspect that suitable equipment is out of the reach of amateurs. Might be fun to try, though.

Agreed, I would not expect to see parallax at that distance even with great equipment. But a 40 day orbit must indicate a pretty high orbital velocity so I wondered if there might not be a noticeable shift in the spectrum.

Have to do a bit more reading. The system may have other properties we could explore.

Detecting the radial velocity variations should be within the capabilities of this amateur designed and built spectrograph:

http://www.astrosurf.com/buil/us/spe2/hresol.htm

Medium resolution (here R = 3000) is likely all that is required. I used a similar spectrograph to take data on the eclipsing binary u Her. One should note that the spectral lines of B stars are often a bit wide so determining their wavelength can be a problem.

Anyway there are also high resolution options open to the amateur. At R = 17,000 there is LHIRES III.

https://www.shelyak.com/produit/lhires-iii/?lang=en

At medium resolution the Baader Dados with the 900 lines/mm grating could also work.

https://www.baader-planetarium.com/en/b ... graph.html

[notFritzArgelander]

A 40-day orbit is likely too small to detect the star's orbital motion directly with amateur equipment. You might be able to tell spectroscopically, though I suspect that suitable equipment is out of the reach of amateurs. Might be fun to try, though.

Agreed, I would not expect to see parallax at that distance even with great equipment. But a 40 day orbit must indicate a pretty high orbital velocity so I wondered if there might not be a noticeable shift in the spectrum.

Have to do a bit more reading. The system may have other properties we could explore.

Detecting the radial velocity variations should be within the capabilities of this amateur designed and built spectrograph:

http://www.astrosurf.com/buil/us/spe2/hresol.htm

Medium resolution (here R = 3000) is likely all that is required. I used a similar spectrograph to take data on the eclipsing binary u Her. One should note that the spectral lines of B stars are often a bit wide so determining their wavelength can be a problem.

Anyway there are also high resolution options open to the amateur. At R = 17,000 there is LHIRES III.

https://www.shelyak.com/produit/lhires-iii/?lang=en

At medium resolution the Baader Dados with the 900 lines/mm grating could also work.

https://www.baader-planetarium.com/en/b ... graph.html

The difference here is that a medium resolution spectrometer would be adequate to detect the wobble. A high resolution instrument is needed to make meaningful measurements.

[GCoyote]

Not visible from our latitudes. We'll have to see who in the southern locales wants to try this.

[KingClinton]

Not visible from our latitudes. We'll have to see who in the southern locales wants to try this.

I would be more than happy to try.
Just purchase the suggested gear and post it down my way!

[smp]

Here's another article this morning from Ars Technica:
"Astronomers have discovered closest black hole yet in trinary star system"

https://arstechnica.com/science/2020/05 ... ar-system/

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[smp]

An article on Sky & Telescope says "maybe":

"Closest Black Hole to Earth? Maybe"

https://skyandtelescope.org/astronomy-n ... rth-maybe/

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[notFritzArgelander]

FWIW I think the "maybe" is pretty thin. Likely is better.

[Lola Bruce]

Wrong wrong wrong. The biggest and closest is Washington DC. And it can suck all the joy and money out of anything.

Bruce

[AntennaGuy]

Wrong wrong wrong. The biggest and closest is Washington DC. And it can suck all the joy and money out of anything.
Bruce

Ha ha ha.
https://i.stack.imgur.com/QGRkK.jpg

[GCoyote]

Not visible from our latitudes. We'll have to see who in the southern locales wants to try this.

I would be more than happy to try.
Just purchase the suggested gear and post it down my way!

As soon as I win the lottery, you've got a deal.