Download - Asteroseismology: Looking inside stars
Asteroseismology: Looking inside stars
Jørgen Christensen-Dalsgaard & Hans Kjeldsen Aarhus Universitet
Rømer
Asteroseismology:Looking inside stars
5
Mission Objective and Critical mission requirements
Rømer (1999-200?)
Rømer Payload: MONS Telescope DesignOrbitPlatform Design
10
Mission Objective and Critical mission requirements
Rømer primary mission objective
To provide new insights into the structure and evolution of stars, using them as laboratories tounderstand physics under extreme conditions, by studying oscillations in a sample of 20 solar-typestars.
Mission Objective and Critical mission requirements
Rømer secondary mission objectives
1. To study the structure and evolution of stars hotter and more massive than the Sun (delta Scuti and rapidly oscillating Ap stars) by measuring their oscillations.
2. To study variability in a large sample of stars of all types.
Mission Objective and Critical mission requirements
Scientific aims (Rømer):
• Properties of convective cores, including overshoot• Structure and age of low-metallicity stars• Physical properties of stellar matter• Stellar helium abundances• Effects and evolution of stellar internal rotation• Dependence of the excitation of oscillations• Surface features• Convective motions on stellar surfaces• Reflected lights from exoplanets (and transits)
Mission Objective and Critical mission requirements
Rømer Payload Objectives
• Photometric precision: We must be able to detect oscillations that have very low amplitudes (1-10 ppm)
• Temporal coverage: Each primary target must be observed almost continuously for at least one month, ideally substantially longer
• Sky coverage: The science goals require access to the whole sky over the course of the mission
Colour oscillation signal
Solar data from VIRGO on SOHO
Key mission parametersMission parameter Description
Size 60 x 60 x 71 cm
Primary payload MONS optical telescope and Field Monitor
Secundary instruments 2 star imagers
Weight 99 kg
Power consumption 55 Watt, average
Downlink datarates Max. 24 Mbyte/day
OrbitHighly elliptical (Molniya)
Apogee: 40.000 km - Perigee: 600 kmInclination: 63.4
Launch SOYUZ/FREGAT
32 cm telescope
Field Monitor
Star Tra
cker #
1
Star Tra
cker #
2
15
Image on CCD
Molniya orbit: Rømer
Orbit is a 400 x 40,000km 63.4° inclination
a = 26600 km i = 63.4 e=0.75 P=11.967 hrs.
Change in right ascension of theascending node:
-0.030 deg/day
Change in argument of perigee:
0.000 deg/day
ADCS:Attitude Determinationand Control Subsystem
Communication
Structure andMechanisms
PowerThermal
CDH:Command and DataHandling Subsystem
ADCS:Attitude Determinationand Control Subsystem
Communication
Structure andMechanisms
PowerThermal
CDH:Command and DataHandling Subsystem
ADCS:Attitude Determinationand Control Subsystem
Communication
Structure andMechanisms
PowerThermal
CDH:Command and DataHandling Subsystem
20
ADCS:Attitude Determinationand Control Subsystem
Communication
Structure andMechanisms
PowerThermal
CDH:Command and DataHandling Subsystem
ADCS:Attitude Determinationand Control Subsystem
Communication
Structure andMechanisms
PowerThermal
CDH:Command and DataHandling Subsystem
ADCS:Attitude Determinationand Control Subsystem
Communication
Structure andMechanisms
PowerThermal
CDH:Command and DataHandling Subsystem
ADCS:Attitude DeterminationAnd Control Subsystem
Communication
Structure andMechanisms
PowerThermal
CDH:Command andData HandlingSubsystem
ADCS:Attitude DeterminationAnd Control Subsystem
Communication
Structure andMechanisms
PowerThermal
CDH:Command andData HandlingSubsystem
ADCS:Attitude DeterminationAnd Control Subsystem
Communication
Structure andMechanisms
PowerThermal
CDH:Command and DataHandling Subsystem
ADCS:Attitude DeterminationAnd Control Subsystem
Communication
Structure andMechanisms
PowerThermal
CDH:Command andData HandlingSubsystem
ADCS:Attitude DeterminationAnd Control Subsystem
Communication
Structure andMechanisms
PowerThermal
CDH:Command andData HandlingSubsystem
Ground-based support observations
Preparatory observations•Characterization of targets (effective temperature, luminosity, composition)
•Charcterization of target field, including possible interfering objects
Parallel observations•For some objects, simultaneous ground-based velocity observations, for characterization of strongest modes.