Chandra
Orion Ultradeep Project
Young Suns
Using a complete sample
of 1 solar mass Orion stars in the COUP field, we establish that all analogs
of the young Sun exhibit incredibly high levels of magnetic activity.
At left, we see a typical example of the 13-day COUP lightcurve, showing
multiple flares over the 13-day observation. At right, we see an extreme
case: the second flare is perhaps the most luminous X-ray flare ever detected
in a solar type star, with peak luminosity of 2x1032 erg/s in the 0.5-8 keV
X-ray band. This is thousands of times stronger than the brightest
flares seen on the contemporary Sun.
The net effect is that X-rays, and the energetic protons and shocks that accompany X-rays in magnetic reconnection flares, may have strong effects on the protoplanetary disks that surround young stars. X-ray ionization, though at a low level, penetrates deep into the disk where it can induce turbulence, which in turn increases viscosity and inhibits planet migration. The X-rays or shocks can melt small solid clumps into chondrules, and energetic particles can produce unusual isotopes in these solids, effects which are seen in ancient meteorites which were formed when the Sun was young. The COUP flares seen in Orion solar analogs may this help understand processes underlying the formation of structures in our solar system.
The full paper on COUP X-ray evolution is:
The Active Young Suns of Orion
S.J. Wolk, F.R. Harnden Jr., E. Flaccomio, G. Micela, F. Favata. A.E. Glassgold, S. Shang, E.D. Feigelson
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Young Suns
Here
we see the distribution of energies (again in the 0.5-8 keV band) for all
flares seen in the COUP young Suns sample. They are typically 1034-10-36
ergs. The distribution is again similar to that seen in the Sun (curve)
but displaced to energies thousands of times higher. The Orion population
flares are also much more frequent than powerful flares in the Sun today.
The net effect is that X-rays, and the energetic protons and shocks that accompany X-rays in magnetic reconnection flares, may have strong effects on the protoplanetary disks that surround young stars. X-ray ionization, though at a low level, penetrates deep into the disk where it can induce turbulence, which in turn increases viscosity and inhibits planet migration. The X-rays or shocks can melt small solid clumps into chondrules, and energetic particles can produce unusual isotopes in these solids, effects which are seen in ancient meteorites which were formed when the Sun was young. The COUP flares seen in Orion solar analogs may this help understand processes underlying the formation of structures in our solar system.
The full paper on COUP X-ray evolution is:
The Active Young Suns of Orion
S.J. Wolk, F.R. Harnden Jr., E. Flaccomio, G. Micela, F. Favata. A.E. Glassgold, S. Shang, E.D. Feigelson
Back to the COUP home page