IPHIR InterPlanetary Helioseismology by Irradiance measurements

1
IPHIRInterPlanetary Helioseismology by
Irradiance measurements

• Scientific Results
• T. Toutain

2
IPHIR Instrument

• Helioseismology instrument aboard the 2 probes of
  the USSR Phobos mission to Mars.
• Triple sunphotometer (335,500 and 862 nm)
  measuring solar irradiance in the continuum.
  2-axis solar sensor.
• Institutes and persons involved
• PMOD/WRC (Davos, Switzerland) - C.
  Fröhlich(P.I.), Ch. Wehrli, H.J. Roth
• LPSP (Verrières-le-buisson ) Boudine, J.C. Vial
• Space Science Department of ESA - R.M. Bonnet, V.
  Domingo
• Crimean Astrophysical Observatory - A. Bruns,
  V.A. Kotov, D.N. Rachkovskii
• Central Research Institute for Physics (Hungary)
  Z. Kollath

3
IPHIR aboard a Phobos Probe
Courtesy of C. Fröhlich, and H. Roth, Davos
4
IPHIRs team of experts
Courtesy of C. Fröhlich, and H. Roth, Davos
5
IPHIR Model
Courtesy of C. Fröhlich, and H. Roth, Davos
6
Phobos mission

• The last mission undertaken by the USSR was that
  of Phobos - a mission involving two probes
  (Phobos 1 and 2) aiming at Mars.
• Phobos 1, launched 7 July 1988, never made it to
  Mars, losing contact with Earth on September 2,
  1988. The problem was later found to be in a
  software upload problem on August 29/30 that
  caused the craft's attitude thrusters to power
  down, resulting in the craft no longer pointing
  to the sun and the solar arrays not charging the
  batteries.
• Phobos 2, launched 12 July 1988, reached Mars,
  and it gathered data on the Sun, interplanetary
  medium, Mars, and Phobos. However, a maneuver
  before the final phase of the mission to place
  the craft within 50 m of Phobos' surface to
  release two craft - a mobile "hopper' and a
  stationary platform - resulted in loss of
  communication. The mission ended when there was
  unsuccessful signal acquisition on March 27,
  1989. The cause was traced to an on-board
  computer error.

7
Power Spectrum forFirst-Week of Data
8
IPHIR Power Spectrumof the 5-minute oscillations
9
5min. oscillations
10
Solar oscillation Stochastic Behaviour
11
Time-Frequency Domain Excitation of solar
oscillations
12
Solar Oscillation Correlation
13
Conclusions

• Uninterrupted long duration observations (160
  days). Oscillation parameters determined
  accurately.
• Solar oscillations are excited by the solar
  convection
• Solar oscillations might be correlated(?)
• Guideline for next-generation (VIRGO/SOHO) and
  asteroseismology (COROT).
• Thanks Boudine for your advices!