1. Asteroseismology: Looking inside stars Jørgen Christensen-Dalsgaard & Hans Kjeldsen Aarhus Universitet Rømer

2. Asteroseismology: Looking inside stars Hans Kjeldsen – Aarhus Universitet Ørsted: 1999 Rømer: 200? Danish Small Satellite Programme

3. Asteroseismology: Looking inside stars Hans Kjeldsen – Aarhus Universitet Danish Small Satellite Programme Aarhus Universitet Dansk Rumforskningsinstitut TERMA A/S

5. Looking inside stars

6. Asteroseismology: Looking inside stars

9. 5

14. Observing the stars

15. Atmospheric Scintillation Observing the stars

17. Measuring Oscillations in Nearby Stars: MONS

18. Mission Objective and Critical mission requirements Rømer (1999-200?) Rømer Payload: MONS Telescope Design Orbit Platform Design 10

19. 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.

20. 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.

21. 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)

22. 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

23. Colour oscillation signal Solar data from VIRGO on SOHO

24. Key mission parameters Mission parameterDescription Size60 x 60 x 71 cm Primary payloadMONS optical telescope and Field Monitor Secundary instruments2 star imagers Weight99 kg Power consumption55 Watt, average Downlink dataratesMax. 24 Mbyte/day Orbit Highly elliptical (Molniya) Apogee: 40.000 km - Perigee: 600 km Inclination: 63.4  LaunchSOYUZ/FREGAT

25. 32 cm telescope Field Monitor Star Tracker #1 Star Tracker #2

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31. Image on CCD

34. Molniya orbit: Rømer Orbit is a 400 x 40,000km 63.4° inclination a = 26600 kmi = 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

36. ADCS: Attitude Determination and Control Subsystem Communication Structure and Mechanisms Power Thermal CDH: Command and Data Handling Subsystem

37. ADCS: Attitude Determination and Control Subsystem Communication Structure and Mechanisms Power Thermal CDH: Command and Data Handling Subsystem

38. ADCS: Attitude Determination and Control Subsystem Communication Structure and Mechanisms Power Thermal CDH: Command and Data Handling Subsystem 20

39. ADCS: Attitude Determination and Control Subsystem Communication Structure and Mechanisms Power Thermal CDH: Command and Data Handling Subsystem

40. ADCS: Attitude Determination and Control Subsystem Communication Structure and Mechanisms Power Thermal CDH: Command and Data Handling Subsystem

41. ADCS: Attitude Determination and Control Subsystem Communication Structure and Mechanisms Power Thermal CDH: Command and Data Handling Subsystem

42. ADCS: Attitude Determination And Control Subsystem Communication Structure and Mechanisms Power Thermal CDH: Command and Data Handling Subsystem

43. ADCS: Attitude Determination And Control Subsystem Communication Structure and Mechanisms Power Thermal CDH: Command and Data Handling Subsystem

44. ADCS: Attitude Determination And Control Subsystem Communication Structure and Mechanisms Power Thermal CDH: Command and Data Handling Subsystem

45. ADCS: Attitude Determination And Control Subsystem Communication Structure and Mechanisms Power Thermal CDH: Command and Data Handling Subsystem

46. ADCS: Attitude Determination And Control Subsystem Communication Structure and Mechanisms Power Thermal CDH: Command and Data Handling Subsystem

47. 2009? 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.

49. 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.