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KATSOVA M.M. , LIVSHITS М.А. Sternberg Astronomical Institute, Moscow State University IZMIRAN, Troitsk HOW STELLAR FLARE EXPERIENCE CAN HELP IN SOLAR INVESTIGATIONS?. Our SUN. The soft X-ray emission of the late-type stars. - ROSAT, 0.1 – 2.4 keV - The Sun - PowerPoint PPT Presentation
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KATSOVA M.M., LIVSHITS М.А.
Sternberg Astronomical Institute, Moscow State UniversityIZMIRAN, Troitsk
HOW STELLAR FLARE EXPERIENCE CAN HELP IN SOLAR INVESTIGATIONS?
Our SUN
The soft X-ray emission of the late-type stars
- ROSAT, 0.1 – 2.4 keV
- The Sunat the same spectal range, max, min
- Stars from J.Wright et al, 2004
- Stars of HK Project S.Baliunas et al.
The soft X-ray emission of the late-type stars
The chromospheric radiation of the late-type stars
Spots on active late-type stars
• Thus, the Sun enters naturally in a family of cyclic stars:
the Sun among the active stars with cycles is a hotter star, rotating comparatively faster, while solar spots cover relatively less area than spots on active stars.
Some features : cycles
1992 1998
• Evidence for coronal activity cycles on 61 Cyg A and B
• A.Hempelman, J.H.M.M.Schmitt, S.L.Baliunas and R.A.Donahue
A & A (2003) V.406, L.39
61 Cyg A
Ca II
X-Ray
ROSATHRI
Some features: cycles and long-term variability of the Sun and some stars
1975 2000 1965 2000
X-rays
Ca II
Solar irradiance
HD 1835 Optical continuumV
Ca II
HD 10476
V
Ca II
STELLAR CORONAE: spectra, XMM-Newton
M.Güdel, “X-ray astronomy of stellar coronae”. Astron. Astrophys. Rev. 2004
STELLAR CORONAE : ЕМ, Т
6.0 7.0 log T
7.0
6.0
log L(x) 27 29 31
52
50
48
46 M.Güdel. “X-ray astronomy of stellar coronae”.
Astron. Astrophys. Rev. 2004
log EM log T
IMPULSIVE STELLAR FLARES
GAS-DYNAMIC MODELLING:
Livshits, Badalyan, Kosovichev and Katsova, 1981, Solar Phys. 73, 269
Katsova, Boiko, Livshits, 1997A & A , 321, 549
IMPULSIVE FLARES: results and experience
Interpretation of simultaneous observations at various spectral ranges
Estimation of amount of the evaporated plasma
The most reliable method of estimation of the stellar flare area in optics
Analysis of secondary processes allows us to conclude about properties of primary energy release
Flares on red dwarf stars
M. Guedel
“X-ray astronomy
of stellar coronae”
Astron. Astrophys. Rev.
2004
Flares on red dwarf stars
Prox Cen
EQ Peg
Flare duration in optics – 5 minThe EM of flare coronal loops is much
more than it was expected from the optical data
Katsova, Livshits, J.H.M.M.Schmitt 2002, 2005 “Short powerful flare on EQ Peg as an analog of solar compact flares”
UX Ari
I.M.Livshits, M.A.Livshits, R.Pallavicini, 2003, Adv.Space Res. 32(6), 1181
CORONAL HEATING
Red dwarf stars -microflaring
G-K stars with cycles –
plasma heating in coronal loops
Active F-G dwarfs and subgiants – prolonged non-stationary
processes in corona
The Sun among active late-type stars with cycles is a typical one.The soft X-ray emission of stellar coronae allows us to analyse processes in different physical conditions and to distinguish phenomena developing both in strong local and large-scale magnetic fields. It helps to understand how can change the solar corona if heating increases by 3-4 orders of a magnitude and will be realized at small and large spatial structures.If solar non-stationary phenomena are characterized by energies up to 1032 ergs, so stellar flares give possibility to investigate much more powerful events with total energies up to 1036 ergs. Therefore there is a chance to observe phenomena associated either with a pulse only or with prolonged primary energy release
HOW STELLAR FLARE EXPERIENCE CAN HELP IN SOLAR INVESTIGATIONS? CONCLUSIONS
The End