DARWIN The InfraRed Space Interferometer

18
DARWIN The InfraRed Space Interferometer

description

DARWIN The InfraRed Space Interferometer. Status of exo-planet search. Stars (Solar type) observed: +3000 Planets detected: ~ 86 Radial velocity measurement precision 1-2 m/s intrinsic limit? Earth requires 0.1 m/s. Occultation: Planet orbiting HD209458 P = 3.5 days - PowerPoint PPT Presentation

Transcript of DARWIN The InfraRed Space Interferometer

Page 1: DARWIN The InfraRed Space Interferometer

DARWINThe InfraRed Space Interferometer

Page 2: DARWIN The InfraRed Space Interferometer

Status of exo-planet searchStatus of exo-planet search• Stars (Solar type) observed: +3000 • Planets detected: ~ 86• Radial velocity measurement precision

– 1-2 m/s intrinsic limit?– Earth requires 0.1 m/s

Occultation:Planet orbiting HD209458P = 3.5 days

m = 0.7 Mjup

Rp = 1.4 Rjup

Page 3: DARWIN The InfraRed Space Interferometer

Status of exo-planet searchStatus of exo-planet search

Page 4: DARWIN The InfraRed Space Interferometer

Search For Extrasolar PlanetsSearch For Extrasolar Planets COROT

• COROT has two main scientific programs working simultaneously on adjacent regions of the sky:

• ASTEROSEISMOLOGY • SEARCH FOR

EXTRASOLAR PLANETS (“Super-Earths”- if they exist!)

Page 5: DARWIN The InfraRed Space Interferometer

Search For Extrasolar PlanetsSearch For Extrasolar Planets EDDINGTON

• Habitable Planets

• Jupiter /Sun =1 %

• Earth/ Sun = 8.4*10-5

• Mars/Sun = 3*10-5

• Photometric precision require space mission

> EDDINGTON determines minimum size of DARWIN

Page 6: DARWIN The InfraRed Space Interferometer

Direct detection of nearby EarthsDirect detection of nearby EarthsTwo major difficulties:

1. Contrast: 107 in the infrared for a Sun-Earth system

2. Angular Separation: 0.1 arcsec for a Sun-Earth system at 10pc

7

106

Dynamic range and resolution

Page 7: DARWIN The InfraRed Space Interferometer

Searching for nearby EarthsSearching for nearby Earths

Candle light 0.3m from lighthouse at a distance of

1000km

Light is drenched in radiation from

the star

Page 8: DARWIN The InfraRed Space Interferometer

interferometerinterferometer

Recomb.

Tele-scope

1

Tele-scope

2

Dsin

NullingNulling

Page 9: DARWIN The InfraRed Space Interferometer

Principle of a Bracewell nulling interferometer

Pupil plane recombination no image(the only thing we detect is an integrated flux)

bright output

dark output

20 m

500

mill

i-ar

csec

Transmission map

NULLING INTERFEROMETRYNULLING INTERFEROMETRY

0

Page 10: DARWIN The InfraRed Space Interferometer

The InfraRed Space InterferometerDARWIN

• 6 telescopes (1.5m)

• Hexagonal configuration

• Beam combiner

• Passive cooling (40 K)

Page 11: DARWIN The InfraRed Space Interferometer

Concept• Infrared interferometer

– Multi-aperture : 1.5 m telescopes baselined– Laurance class configuration– Wide band spectroscopy

• Free-flyer– Micropropulsion– Laser & RF metrology

• Wavefront filtering– Enabling technology – relaxes requirement

on WF qualitiy

Page 12: DARWIN The InfraRed Space Interferometer

The InfraRed Space InterferometerDARWIN

The Solar system as viewed from 10 pc on the 1:st of January 2001 with the Darwin baseline system

Venus

Mars

Earth

Nulled Sun

Page 13: DARWIN The InfraRed Space Interferometer

Characterizing nearby Earth’s

• We thus not only want to detect planets similar to ours but also characterize them from the light they produce

Page 14: DARWIN The InfraRed Space Interferometer

Characterizing EarthsCharacterizing EarthsCalculated atmospheric

spectra (= 200)

Photo

n m

-2

s-1

0

2

4

6

8

10CO

2

6 8 10 15 20 m

300K BB

0

2

4

6

8

10O

3 (telluric)

6 8 10 15 20 m

0

2

4

6

8

10 H20

Observed spectra

0

2

4

6

8

10

Earth

H2O O3 CO2

6 8 10 15 20 m

Mars (x 4)

8

4

2

0

6

0

2

4

6

8

10 Venus (x1.5)

Page 15: DARWIN The InfraRed Space Interferometer

Search for exo-life

• What is life? contains information

can self-replicate

can evolve

• Life on Earth as a reference:

Carbon (organic) chemistry in watersolution

• Goal 2: Astrobiology

Page 16: DARWIN The InfraRed Space Interferometer

Search for exo-lifeSearch for exo-life• Attempt to detect life by remote sensing. Probably one of the most difficult problems in observational astronomy…

• Most likely criterion is simultaneous presence of liquid H2O together with presence of O2

1. O2 produced by life

2. O2 very reactive gas / rocks… if not continuously

produced it vanishes in < million yrs

3. O3 better than O2. It is logaritmically dependant on

amount of O2+ spectral lines in the IRPresence of O3 = signature of life

unless non-biotic production

Page 17: DARWIN The InfraRed Space Interferometer

Search for exo-life

- for > 20 yrs, no abiotic production of O3 found when:

• O3 with liquid H2O• atmosphere at T ~ 270 K (Habitable Zone)

• Qualifying the H2O / O 3 criterion:

If criterion stands, organic life can be searched for

Page 18: DARWIN The InfraRed Space Interferometer

NASA’s Terrestrial Planet Finder

Four 3.5m telescopes

Identical objectives to Darwin

Good basis for future collaboration