350 likes | 496 Views
Asteroseismology: Looking inside stars. Rømer. Jørgen Christensen-Dalsgaard & Hans Kjeldsen Aarhus Universitet. Asteroseismology: Looking inside stars. 5. 10. Mission Objective and Critical mission requirements. Rømer Payload: MONS Telescope Design Orbit Platform Design.
E N D
Asteroseismology: Looking inside stars Rømer Jørgen Christensen-Dalsgaard & Hans Kjeldsen Aarhus Universitet
Asteroseismology: Looking inside stars
10 Mission Objective and Critical mission requirements Rømer Payload: MONS Telescope Design Orbit Platform Design Rømer (1999-200?)
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 to understand physics under extreme conditions, by studying oscillations in a sample of 20 solar-type stars.
Mission Objective and Critical mission requirements • Rømer secondary mission objectives • 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. • 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
Mission 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 Orbit Highly elliptical (Molniya) Apogee: 40.000 km - Perigee: 600 km Inclination: 63.4 Launch SOYUZ/FREGAT Key mission parameters
Star Tracker #1 32 cm telescope Star Tracker #2 Field Monitor
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 the ascending node: -0.030 deg/day Change in argument of perigee: 0.000 deg/day
ADCS: Attitude Determination and Control Subsystem Communication CDH: Command and Data Handling Subsystem Power Thermal Structure and Mechanisms
ADCS: Attitude Determination and Control Subsystem Communication CDH: Command and Data Handling Subsystem Power Thermal Structure and Mechanisms
20 ADCS: Attitude Determination and Control Subsystem Communication CDH: Command and Data Handling Subsystem Power Thermal Structure and Mechanisms
ADCS: Attitude Determination and Control Subsystem Communication CDH: Command and Data Handling Subsystem Power Thermal Structure and Mechanisms
ADCS: Attitude Determination and Control Subsystem Communication CDH: Command and Data Handling Subsystem Power Thermal Structure and Mechanisms
ADCS: Attitude Determination and Control Subsystem Communication CDH: Command and Data Handling Subsystem Power Thermal Structure and Mechanisms
ADCS: Attitude Determination And Control Subsystem CDH: Command and Data Handling Subsystem Communication Structure and Mechanisms Thermal Power
ADCS: Attitude Determination And Control Subsystem CDH: Command and Data Handling Subsystem Communication Structure and Mechanisms Thermal Power
ADCS: Attitude Determination And Control Subsystem Communication CDH: Command and Data Handling Subsystem Structure and Mechanisms Thermal Power
ADCS: Attitude Determination And Control Subsystem CDH: Command and Data Handling Subsystem Communication Structure and Mechanisms Thermal Power
ADCS: Attitude Determination And Control Subsystem CDH: Command and Data Handling Subsystem Communication Structure and Mechanisms Thermal Power
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.