Jump to content

More space news!


tkdguy

Recommended Posts

Re: More space news!

 

The Jan 5 issue of Nature has a note announcing the discovery of a small (3 earth masses) gas cloud which is approaching the Galaxy's central black hole and is expected to go through closest approach in mid-2013. Not all of it will survive, and it'll be interesting to see how big a flare-up the event causes in Sagittarius A*'s emissions (which have been more or less steady during the period over which we've been able to observe it). The cloud is expected to sheared out into a long stream (or many small cloudlets), much of which will get accreted onto the black hole over mid-to-late next year.

 

The best-fit orbital elements they derive for the cloud are

Parameters of Keplerian orbit around the 4.31 × 10^6 M⊙ black hole at R0 = 8.33 kpc

  • Semi-major axis, a: 521 ± 28 mas (mas == milli-arc seconds)
  • Eccentricity, e: 0.9384 ± 0.0066
  • Inclination of ascending node, i: 106.55 ± 0.88 degrees
  • Position angle of ascending node, Ω: 101.5 ± 1.1 degrees
  • Longitude of pericentre, ω: 109.59 ± 0.78 degrees
  • Time of pericentre, tperi: 2013.51 ± 0.035 (this is a date: that is, 0.51 of the way through 2013)
  • Pericentre distance from black hole, rperi: 4.0 ± 0.3 × 10^15 cm ~= 270 AU = 3,140 RS (RS == Schwarzschild radius of the central black hole)
  • Orbital period, to: 137 ± 11 years

Link to comment
Share on other sites

Re: More space news!

 

Well, your options are X-rays, gamma-rays, radio, and infrared. The high energy stuff is all satellite instruments, of course, and I admit I don't know what's up there right now. Radio variability tends to be slow, so intermittent peeks are OK. Here, infrared means 2.2 microns and longward, and I think that'll all be monster telescope work (the eight-to-ten-meter telescopes and up), rather finely time-sliced, unless something really spectacular happens and the observatory leadership yanks the time away.

 

It's just one more thing for the TACs (Telescope Allocation Committees) to wrestle with. Kinda like when Shoemaker-Levy 9 fell into Jupiter, back at the dawn of the Web.

Link to comment
Share on other sites

Re: More space news!

 

 

Interesting paper. Note they don't have direct detection of water vapor in the atmosphere; rather, the observations require an atmosphere made of gases with a higher molecular weight than hydrogen or helium. Water vapor is a viable alternative (it is heavy enough to satisfy the observational constraints, and you expect it to be an abundant substance) but it is not the only alternative. I think N2 or CO2 would work too. Presumably O2 would also, but the very strong spectral features of O2 would show up and be detectable almost instantly as soon as you could look for them from space (you have no hope of detecting those when you have to look through Earth's atmosphere).

Link to comment
Share on other sites

Re: More space news!

 

If you can't be an astronaut' date=' you can still be a NASA space food taster.

If think you didn't read the trequrements completely:

Though the entirety of the study will take place here on Earth, the study is seeking those with NASA-level qualifications. Namely, participants should have a bachelors in the sciences, professional experience, the ability to pass a physical examination, and a history of conducting field research.
Link to comment
Share on other sites

Re: More space news!

 

 

It says that The bigger/denser (and thus deeper the gravity well), the better an object is at capturing & retaining rogues.

 

Add that with this article:

 

Hundreds of "Rogue" Black Holes May Roam Milky Way

And it seems like it could be a real craps shoot out there.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...