PDA

View Full Version : Discussion: X-Ray Portrait of Proxima Centauri



Fraser
2004-Nov-10, 05:57 PM
SUMMARY: NASA's Chandra X-Ray Observatory took this image of red dwarf star Proxima Centauri, our closest stellar neighbour (after the Sun, of course). The image shows that its surface is in a constant state of turmoil, with flares occurring almost continuously. Proxima Centauri has only 1/10th the mass of our own Sun, and the conversion of hydrogen to helium happens much more slowly. This creates turbulent, convective motion throughout its interior, which stores up magnetic energy - the energy is what creates all the flares.

What do you think about this story? Post your comments below.

antoniseb
2004-Nov-10, 06:06 PM
I had always though that eventually, mankind would build a sort of ring-world around a nearby red dwarf as a safe haven for that distant future when our sun stops functioning. But every time I read about detailed studies of these objects they are dangerous flare machines.

I am interested in knowing more about the scale of the flaring around Proxima and other red dwarfs.

astromark
2004-Nov-10, 10:28 PM
:huh: Yes, it does not look like a safe place to build our future colony around... but what of the two smaller targets in this image. background stars, or could they be planets?

antoniseb
2004-Nov-10, 11:51 PM
Originally posted by astromark@Nov 10 2004, 10:28 PM
could they be planets?
They are probably outside our galaxy. Planets like jupiter do sometimes give off xrays, but it wouldn't be THAT bright.

Guest_qraal
2004-Nov-10, 11:53 PM
Hi All

antoniseb, the flares of a red dwarf are akin to flares on the Sun and a planet's magnetic field and its atmosphere should be sufficient to minimise the effects of flares. What they do also is heat things up, but only briefly so while they would be nasty at noon overall the energy buffers (oceans etc) of a planet would moderate the climatic effects. They also provide high-energy photons that red stars otherwise lack, thus allowing oxygen-making photosynthesis, which some have thought lacking around red dwarfs.

As far as moving to a red star goes I am not overly keen on the concept because I can imagine means that an advanced civilisation might manipulate its own star to prolong its life. Stars as big as the Sun only have a limited amount of hydrogen in their cores because the core is segregated from the rest of the star. Only about ~ 10% of the Sun's hydrogen is available for fusion. Red-dwarfs are totally convective so their effective lifespan is increased ~ 10-fold over Sun-like stars. Gregory Benford has suggested using vast magnetic fields to cause convective motion in the deep Sun - if feasible the Sun's life can be extended to ~ 120 billion years.

qraal

zephyr46
2004-Nov-11, 12:21 AM
They would be some of the first found by X-ray reflection wouldn't they?

I am glad they have done this. As the nearest star, after our Sun, there has been to little attention on Proxima, especially in the infared and X-ray.

Proxima Centauri (http://www.solstation.com/stars/alp-cent3.htm) also demonstrates Red Dwarf and Flare Star attributes. to actually study Proxima throughout its cycle (http://www.eso.org/outreach/press-rel/pr-2002/pr-22-02.html#phot-27c-02) would provide a great amount of detail with which to compare to our Sun, any sort of survey could include Alpha Cent A and B (http://homepage.sunrise.ch/homepage/schatzer/Alpha-Centauri.html) as well, two stars very similar to the Sun.

Just check out the SOHO (http://sohowww.nascom.nasa.gov/) website to see the study of our sun at most wavelengths.

http://sohowww.nascom.nasa.gov/hotshots/2004_07_02/c3c.gif

(3D Coronal Mass Ejection)

I guess you'd see more CMEs than flares on a flare star?

Ulysses (http://sci.esa.int/science-e/www/area/index.cfm?fareaid=11) (News (http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=31209&farchive_objecttypeid=12&farchive_objectid=30910&fareaid_2=63)) is also interesting in the study of our sun.

om@umr.edu
2004-Nov-11, 04:45 AM
This is an interesting story.

Especially the statement about "turbulent, convective motion throughout its interior, which stores up magnetic energy - the energy is what creates all the flares."

Such statements on magnetic fields and flares on distant stars seem premature when the solar cycle and the origin of the Sun's magnetic fields are unexplained by the standard solar model.

As Astronomy Professor Geoffrey Marcy noted recently,

http://www.berkeley.edu/news/media/release...1_maunder.shtml (http://www.berkeley.edu/news/media/releases/2004/06/01_maunder.shtml)

"The fact is, we still don't understand what's going on in our sun, how magnetic fields generate the 11-year solar cycle, or what caused the magnetic Maunder minimum.

In particular, we don't know how often a sun-like star falls into a Maunder minimum, or when the next minimum will occur. It could be tomorrow."

With kind regards,

Oliver
http://www.umr.edu/~om

zephyr46
2004-Nov-13, 03:06 AM
Exactly!

We should be studying the Sun and Proxima Centauri a lot more closely.