Download Science optical interferometry I

Science with Optical/NIR Interferometers
A. Richichi (ESO Garching)
Interferometry Week
ESO Santiago, 14-16 January 2002
Layout of the Tutorial - I
Interferometers
• Types of interferometers under consideration
• Types of interferometry not considered here
• Characteristics of interferometers vs. science drivers
• Illustration of a few representative facilities
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Interferometry Week, ESO
Santiago 16-01-02
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Layout of the Tutorial - II
Science with Interferometers
Stars & PMS Stars
• Fundamental Stellar Parameters
-
diameters, limb darkening, flattening
temperatures
masses
ages
• Binaries
• Stellar Pulsation
• Circumstellar Matter
• Distances
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Layout of the Tutorial - III
Science with Interferometers ctd.
Exoplanets and BD
• Detection and discrimination
• Basic parameters
• Relationship to other EP/BD detection methods
Extragactic sources
Miscellaneous
• Detection
• Microlensing
• Basic parameters
• Solar system objects
• Observation strategies
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VLTI Science - Main References
ESO Symposia: Science with the VLT - 1994 (Walsh/Danziger)
Science with the VLTI - 1996 (Paresce)
From Extrasolar Planets to Cosmology - 1999 (Renzini)
SPIE Interferometry in Optical Astronomy: 1998 Kona, 2001 JENAM,
2000 Munich (22 papers on science with ground-based
interferometers)
Workshops: i.e., ESO April 2001, June 2001
Schools: i.e., 1999 Michelson Summer School, 2000 NOVA/ESO/ESA
Summer School, 2002 EuroWinter School.
Scientific Objectives of the VLT Interferometer (Paresce, March 2001)
(http://www.hq.eso.org/projects/vlti/, abridged in Messenger, 104)
AMBER Scientific Analysis Report, PDR 2000 - MIDI misc.
Science Demonstration Team, PRIMA White Book, ...
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Layout of the Tutorial - IV
Science with the VLT Interferometer
• Facility instrumentation (¶ Schöller)
- wavelengths & limiting magnitudes
- dates of availability
- scientific applications
• Getting ready to observe with the VLTI
- guidelines on object selection and proposal preparation
- calibrators
• VLTI Data (see Messenger 106, P. Ballester et al.)
- format
- pipeline
- data analysis
• Examples and simulations of VLTI results (given throughout)
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Characteristics of Interferometers
• optical to thermal IR ( 0.5m to 20m)
-
types of detectors
background
atmospheric turbulence (tip-tilt, fringe tracking, AO)
mechanical and optical constraints
• Michelson vs. Fizeau interferometers
- homothetic mapping, field of view
- types of baselines
• number of telescopes
-
number of baselines
beam combination (multi-axial, co-axial)
efficiency
closure phases
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Other Interferometric Methods
• single-telescope
- speckle interferometry
- aperture masking
• multi-telescope
- intensity interferometer
- heterodine detection
- nulling interferometry
• space instruments
- SIM, Darwin, GAIA
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Overview of current Interferometers
facility
CHARA
COAST
GI2T
IOTA
ISI
KECK
LBT
MIRA-I.2
MRO
NPOI
PTI
SUSI
VLTI
funding
location
n. of
apertures (m)
baseline year of
apertures primary secondary max (m) first fringes
USA
Mt. Wilson
UK
Cambridge
F
Calern
USA, F Mt. Hopkins
USA
Mt. Wilson
USA
Mauna Kea
USA, D, I Mt. Graham
J
Tokyo
USA
New Mexico
USA
Arizona
USA
Mt. Palomar
AUS
New South Wales
ESO
Paranal
A. Richichi
6
5
2
2-3
2-3
2(4)
2
2
3
3-6
3
2
4(3)
1.0
0.4
1.5
0.45
1.65
10
8.4
0.30
2.4
0.35
0.40
0.14
8.2
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1.8
1.8
350
1999
48
1991
65
38
1993
75
1988
85(140)
2001
23
in constr.
6
2001
100
funded
64
1994
110
1995
640
130(205)
2000
9
Interferometers on the WEB
facility
CHARA
COAST
GI2T
IOTA
ISI
KECK
LBT
MIRA-I.2
MRO
NPOI
PTI
SUSI
VLTI
A. Richichi
URL
http://www.chara.gsu.edu/CHARA/array.html
http://www.mrao.cam.ac.uk/telescopes/coast/index.html
http://wwwrc.obs-azur.fr/fresnel/gi2t/gi2t.htm
http://cfa-www.harvard.edu/cfa/oir/IOTA/
http://isi.ssl.berkeley.edu/
http://huey.jpl.nasa.gov/keck/
http://medusa.as.arizona.edu/lbtwww/lbt.html
http://tamago.mtk.nao.ac.jp/mira/MIRA-I_2/mira_1_2.html
http://www.physics.nmt.edu/research/MRO.html
http://ftp.nofs.navy.mil/projects/npoi/
http://huey.jpl.nasa.gov/palomar/
http://www.physics.usyd.edu.au/astron/susi/
http://www.hq.eso.org/projects/vlti/
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Design vs. Science Drivers
Baseline Length
• Resolution improves with Baseline
- “correlated” magnitude decreases
- relative errors increase
• Calibrators
-
accuracy vs baseline
magnitude vs baseline
density
boot-strapping
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Wavelength vs. Science Drivers
Wavelength
• Angular Resolution
- resolution  -1
• Atmospheric Turbulence
-
phase errors   -1
isoplanatic patch   6/5
seeing   -1/5
coherence time   6/5
• Source Spectrum
- many (but not all!) sources are red
- spectral features
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Geometry vs. Science Drivers
Telescopes
• Number of telescopes
- number of baselines  N(N-1)
- number of phase closures  (N-1)(N-2)/2
• Beam Combiner
- complexity drives cost (and size)
- efficiency decreases with number of telescopes
- new approaches
• Array Geometry
-
non-redundancy
configuration
NS vs. EW orientation
relocation of telescopes
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Closure Phases
from J.D. Monnier, 1999
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Examples of Array Geometries - CHARA
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Examples of Array Geometries - NPOI
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Examples of Array Geometries - VLTI
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Stellar effective temperatures
Direct check for theoretical models of stellar atmospheres
• determination of physical characteristics
• understanding of energy production/dissipation mechanisms,
stellar evolution, chemical abundances, etc.
• population synthesis models
Fbol = a 2Teff4
•  and Fbol are the keys to direct Teff estimates
• Teff ()½ (Fbol) ¼

( /) < 5% typically required
• 102 stars measured by LO, LBI
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Teff Direct Measurements - a)
Early and intermediate
spectral types, Barnes et
al. (1976)
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Teff Direct Measurements - b)
Late spectral types,
Barnes & Evans (1976)
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Teff Direct Measurements - c)
Late spectral types,
Barnes & Evans (1976)
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Teff Calibration for Cool Giants
Ridgway et al. 1980
Dyck et al. 1996
Perrin et al. 1998
Richichi et al. 1999
Currently 646 measurements
of 253 class III stars in
CHARM catalogue (Richichi
& Percheron 2001)
Teff is still uncertain for types
cooler than M7 (several
parameters at play). Need
monitoring of spectra and
photometry.
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Teff of Mira stars
From Van Belle et al. 1996
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Teff of carbon stars
Teff needs Fbol:
photometric monitoring
is strictly required!
Y Tau
From Richichi et al. 1995
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Teff calibration for carbon stars
From Van Belle et al. 2000
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Multiwavelength monitoring
Teff = 3500 K
 = 2.0mas
Teff = 2500 K
 = 3.9mas
Fbol ~ 6%
V  K
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Teff of cool MS stars
Rationale:
• Direct Teff measurements are very scarce: 7 K and 1M dwarfs (~50 times less
than giants)
• Important implications for many fields of astronomy: most common field stars
• Transition to L-BD regime / Outliers
• Mass loss / envelopes / circumstellar environment
• surface features
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Some cool MS stars visible from Paranal
Name
V
Sp
K
phi(mas)
baseline(m)
16
40
200
not complete nor accurate!
 Cen B
HD 128621
V450 Aql ?
41 Ara
BD+20 4139B
V1365 Ori
eps Ind
HD 45724
HD 45588
HD 210090
BD+29 4582B
NSV 1874
GJ 702A
DY Eri
HD 40397
HD 209709
BD+04 4223
HD 112278
HD 85461
CD-48 3065
DO 4490
A. Richichi
1.33
6.48
5.46
8.18
6.84
4.69
6.2
6.07
6.35
8.3
6.34
4.2
4.41
6.8
6.43
8.6
6.97
6.52
8.1
8.7
K1V
M8V
M0V
M9
M6V
K4.5V
M1
M0
M1
M8
M0V
K0V
K1V
M2.5
M0
M8
M3
M0
M7
M8
-0.67
-0.27
1.86
0.88
1.26
2.19
2.25
2.47
2.4
1.55
2.74
2.37
2.41
2.53
2.83
1.85
2.4
2.92
1.92
1.95
7.20
4.49
2.66
2.43
2.37
2.18
2.13
2.01
1.99
1.94
1.78
1.76
1.74
1.73
1.70
1.69
1.68
1.63
1.63
1.61
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0.851
0.940
0.978
0.982
0.983
0.986
0.986
0.988
0.988
0.989
0.990
0.990
0.991
0.991
0.991
0.991
0.991
0.992
0.992
0.992
visibility ^2
0.336
0.671
0.872
0.892
0.897
0.912
0.916
0.925
0.927
0.930
0.941
0.942
0.943
0.944
0.946
0.946
0.947
0.950
0.950
0.951
0.000
0.005
0.001
0.014
0.019
0.048
0.059
0.089
0.095
0.110
0.170
0.175
0.184
0.190
0.201
0.207
0.211
0.233
0.237
0.243
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Statistics of MS cool stars
700
• Select K-M main sequence
stars
600
16 m
100 m
500
200 m
• V<10, K<5
• Use B-V (measured or
estimated) to infer angular
diameter
• Total ~610 stars
• Best targets 90% < Vis <
20%
# Stars
• Apply Paranal limits
400
300
200
100
0
1
0.98
0.95
0.9
0.5
0.15
0
Visibility
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Simulated Teff calibration
• With 1% absolute error on
visibility, errors on the angular
diameters are between 1% and
5%
7
8
• Assume 5% error on bolometric
flux
10
• Errors in Teff would be 1.8% to
3.8%
11
12
13
4000
3750
3500
3250
3000
7
2750
T eff [K]
8
• Assume 0.5 mag random error on
absolute magnitude
• Simulate random distribution of
200 stars
9
M Bol
M Bol
9
10
11
12
13
4000
3750
3500
3250
3000
2750
T eff [K]
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Teff of PMS stars
Rationale:
• Direct Teff measurements do not exist yet
• Permit model-independent location of the stars in the HR diagram
• Check of theoretical tracks
• Implications for age estimates, star and disk formation mechanisms, ...
Practical difficulties:
• they have very small angular diameters!
• a solar precursor ( 5 R ) has 0.30 mas at the distance of Tau-Aur SFR,
0.8 mas at TW Hya
• effect of circumstellar environment
• effect of spots
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Surface features in T Tau stars
Doppler imaging
of the surface of
a T Tau star,
V410 Tauri.
Adapted from
Surdin & Lamzin
(2001).
Desirable to
model the effects
on visibility.
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The age and masses of PMS stars
From Gomez et al. 1992
Relatively high accuracy
is required on Teff
3x105 yrs
1x106 yrs
3x106 yrs
1x107 yrs
Mazzitelli (1989) tracks
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Resolving PMS stars with the VLTI
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Limb-darkening
Same diameter, 3 different LD
1.2000
Visibility
1.0000
0.8000
Important to measure around the
first zero of the visibility
0.6000
0.4000
0.2000
0.
00
8.
00
16
.0
0
24
.0
0
32
.0
0
40
.0
0
48
.0
0
56
.0
0
64
.0
0
72
.0
0
80
.0
0
88
.0
0
96
.0
0
0.0000
Baseline [m]
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Limb-darkening measurements
NPOI, 0.65 to 0.85 m
3 baselines 19 to 38 m
UD =6.82 mas
LD =7.44 mas
FD =7.85 mas
  ~ 0.1mas
From Wittkowski
et al. (2001)
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Potential LD measurements with VINCI
Psi Phe, preliminary
result: =8.3 ±0.3mas
analysis by M. Wittkowski
ESO/NEVEC IDL DRS
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Asymmetries
Fast rotators.
Recent detection of 14% equator/pole
flattening in Altair (P=10.4hours,
V_eq=210 km/s)
For a solar analogue, flattening is
0.001%
Flattening ratios up to 20% are
expected for many B & A fast rotating
stars. Details of visibility curves will
depend strongly on orientation of the
polar axis, and on surface
temperature (brightness) differences.
Narrow-band and emission line
observations.
Good models are required!
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Binary stars
• orbital motions --> masses
• different informations from different types of binary systems
• frequency among YSOs--> key to star formation
• dynamics and evolution of binary/disk systems
• “Special binary stars”: BD companions, hot Jupiters
Two approaches are available to measure orbital motions:
• accurate visibilities (Self-contained, lower precision)
• narrow-angle astrometry (wrt to nearby stars)
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Main parameters of binary systems
taken from J. Davis, 1996
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Visibilities of binary stars
Simulations of some
representative cases of
binary systems
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Spica: the full picture
taken from J. Davis, 1996
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Binaries among YSO
Apparent excess of binary
stars in Taurus/Auriga, wrt
to the solar stars in the
solar neighbourhood.
Possible excess in
Oph/Sco.
No excess in Orion.
VIMA
VISA
VIMA
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What can the VLTI do?
Short term
Long Term
Survey nearby SFRs
Nearby SFRs
• Resolution range
• Orbits close binaries
• Include all stars
• Disks
Benefits
Distant SFRs
• Calibration
• Potential x103
• Fast science results
• Diversity
Spectroscopy
• SF mechanisms
• IR spec. binaries
Extended SEDs
Survey distant SFRs
• IR companions
• Include fainter stars
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Accurate visibilities vs. diffraction limit
1.0
0.8
Visibility
21.3%
0.6
1.00 mas
1.10 mas
0.4
0.2
0.0
0
20
40
60
80
100 120 140 160 180 200
Baseline [m]
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Orbital motions from accurate visibilities
Binary with two point sources, 1:50 Br. Ratio, J band
1.00
Visibility
0.2%
1.00 mas
1.01 mas
0.95
0.90
0
20
40
60
80 100 120 140 160 180 200
Baseline [m]
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Orbital motions by phase referencing
Narrow-angle astrometry can
measure the separation from a
distant reference star with 10as
accuracy
•
Orbital motions in a 10AU system
(P30 yrs) at 50pc
(0.2” separation)
could be detected
in one day.
•
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Circumstellar Structure
Close circumstellar shells
Mass loss
Close companions, tidal interactions
Jets
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IRC +10216
Note: no long-baseline interferometric observations yet!
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Atmospheres of AGB stars
HST observation
of Mira
(Karovska et al. 1997)
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Circumstellar emission
From Mennesson et al. (2000).
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Asymmetric envelope with the VLTI
Normalized Diameter
Diameter vs. Hour Angle
1.02
1.00
0.98
0.96
0.94
0.92
0.90
0.88
0.86
0.84
0.82
0:00
1:12
2:24
3:36
4:48
6:00
7:12
8:24
UT Time
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VLTI commissioning observations of Mira
33.00
Ang. Diam (mas)
32.00
23-Oct
31.00
24-Oct
30.00
10-Nov
29.00
16-Nov
28.00
18-Nov
27.00
26.00
-3.00
-2.00
-1.00
0.00
1.00
2.00
3.00
Hour Angle
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Detection of the envelope around Mira
40.0
38.0
36.0
34.0
32.0
23-Oct
24-Oct
30.0
10-Nov
16-Nov
28.0
18-Nov
26.0
24.0
22.0
20.0
-20.0
A. Richichi
-15.0
-10.0
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-5.0
0.0
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The environment around YSO
500 AU
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Model for IRAS
16293:1629, adapted
from Surdin & Lamzin
(2001)
55
Herbig AeBe stars
HAEBEs are young intermediate
mass PMS stars
Ages in the 105 and 107 yrs range,
distances 100-300pc
Masses in the 2-8 M range
Analogue to T Tauris
Likely progenitors of Vega-like
debris disk stars
Very large IR excess due to CS
material in a disk, possible site
of planetary formation
some have mm interferometry sizes
of several 100AU (~sec”)
~1AU in K, 10-20AU in N
slides from R. van Boekel, F. Paresce
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Disks around Herbig AeBe stars
SED can be reproduced
by a passive irradiated
flaring disk model
(Dullemond et al.,
2001) determined
mainly by:
m, L, Te and d of star
(known)
total mass and
opacity of dust
Rin, Rout inner and
outer disk radius
Hrim, height of inner
wall
inclination of disk to
LOS
VLTI Objective is to test
the spatial predictions
of the model and to
strongly constrain free
parameter space
57
Model visibilities and parameters
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Other parameters
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Consistency with SED
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Observations of T Tau
Akeson et al. 2001
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Refining dust models by interferometry
Akeson et al. 2001
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Measuring distances by interferometry
Parallax
Astrometry is possible with some interferometers.
Precisions of 10-100 arcsec are possible.
Cepheids
Traditionally the standard candles in the distance scale.
The angular diameter of the nearest ones is now
potentially within reach of interferometers.
Eclipsing Spectroscopic Binaries
An alternative standard candle.
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Cepheid Stars
Rationale:
• Period-Luminosity Law
• Standard Candle
• Non-Radial modes?
• Details of pulsation lightcurves not yet completely understood
What modern interferometry can achieve:
• Measurement of angular diameters, with spectacular improvement over
current data
• A priori information available, high efficiency
• Repeated measurements necessary
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Some Cepheids visibile from Paranal
^2
Data
provided by
P. Kervella
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Zeta Gem
Simulated Observations of Zeta Geminorum with
VINCI/VLTI Siderostats
Angular size
(milliarcsec)
1.750
Single measurement: +/- 4 mas
Absolute calibration: +/- 9 mas
1.700
IOTA/Fluor
1.650
Kervella et al. (2000)
1.600
1.550
1.500
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Phase
Simulation by P. Kervella
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1
Eclisping spectroscopic binaries
Rationale:
• Eclipses give orbital elements in absolute units
• By-product: stellar radii (calibration, still uncertain, could yield distance)
• Astrometric orbit: yield distance with higher accuracy
• Use as a standard candle
Furthermore:
• Case of binaries with partially resolved discs
• Characteristics (br. ratio, period, epoch) can be estimated in advance, high
efficiency
• Repeated measurements desirable
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Orbits of well-detached eclipsing binaries
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Orbits of contact eclipsing binaries
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Eclipsing binaries as M-m indicators
Distance to the LMC from
the eclipsing binary HV
2274 (Guinan et al. 1998,
Udalski et al. 1998).
Uncertainty due to
reddening introduces a
significant difference in
the [M-m]
(18.47 vs. 18.22)
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Santiago 16-01-02
70
Some eclipsing binaries from Paranal
Cross–Identifications
Zet Phe
Del Lib
TZ For
TY Pyx
SZ Psc
V624 Her
HU Tau
Z Her
CD Tau
ZZ Boo
GG Lup
U Oph
Coordinates

d
1.0823082
15.0058349
3.1440093
8.5942722
23.1323786
17.4417247
4.3815830
17.5806980
5.1731153
13.5609518
15.1856375
17.1631716
-55.144474
-8.310820
-35.332759
-27.485869
2.403158
14.243624
20.410500
15.082190
20.075463
25.550736
-40.471760
1.123796
Quick referecence data
V
K
Spectrum a[mas]
estim.
3.97
4.95
6.89
6.90
7.44
6.20
5.86
7.27
6.77
6.78
5.59
5.90
4.3
5.0
5.3
5.3
5.6
5.8
5.9
5.9
5.9
5.9
5.9
5.9
B6V+...
B9.5V
G2V
G5V
K1IV-V+...
A3m
B8V
F4IV-V
F7V
F2V
B7V
B5Vnn+...
0.598
0.684
3.254
1.021
0.792
0.540
0.506
0.716
0.848
0.765
0.351
0.315
Data provided by B. Paczynski
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The hunt for extrasolar planets
Need direct
detection, to derive
separation and
resolve the orbital
parameters.
Interferometry is
the most promising
technique from the
ground.
Mass function of extrasolar planets in units of Jupiter mass detected so far out of ~1000
72
stars from Queloz (ESA SP-451, 2000)
Extrasolar planets as special binary stars
73
Astrometry with PRIMA
Phased implementation plan
Accuracy: 50 arcsec initially, later 10 arcsec
Reference star within 30”
Limiting magnitudes eventually K>18 UTs, 15 ATs.
equip ATs first, later UTs
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Santiago 16-01-02
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Detection without PRIMA
From Lopez & Petrov (1999)
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Extragalactic Science
• Quasars, AGNs, Seyferts
• SNe in distant galaxies
Requirements
Can we find a reference star nearby? PRIMA!
• Limit set by AT/UT, wavelength, visibility, field separation
• Statistical approach
What can we expect to measure?
• Issue of field of view, imaging vs. parametric models
• Does [magnitude x visibility] kill us?
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Interferometry Week, ESO
Santiago 16-01-02
76
NGC 1068
NGC 1068 observed with AO (K, H) [Rouan et al. 1998]
Kmag=9.3 witin 0.2”.
A. Richichi
[J-H]=7.0
[H-K]=3.8
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The visibility of NGC 1068
NGC 1068 by speckle Wittkowski et al. (1998)
K band, 6m (0.076mas)
Note: when the visibility goes down, the SNR goes down.
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Interferometry Week, ESO
Santiago 16-01-02
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The issue of image complexity
Model
4 telescopes, 6 hours
8 telescopes, 6 hours
Simulation made by
C. Haniff (COAST)
79
SN and transient phenomena
Position of photocenter wrt nearby
bright star
t1
New position of
photocenter
Phase
Shift
t2
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Microlensing
Delplancke, Gorski, Richichi (2001)
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Santiago 16-01-02
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Photocenter wobble
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The neutron star RX J185635-3754
Min_d=300 mas
MF606W=26.5
Using
D=61pc
M=1.4M
Predicted shift=0.6mas
Duration ~1 year
Aim: direct mass determination of an isolated
neutron star, with high accuracy and
independently of model assumptions.
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Santiago 16-01-02
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The size of Trans-Neptunian Objects
Aim: direct
determination of the
diameter of TNO.
The largest one,
recently observed
with AVO, has a
size of 1200km @
1.5DN, or ~40mas.
VLTI case: one can measure ~10x smaller TNOs with the VLTI. The luminosity
will decrease correspondingly. KX76 has K~18, so we need to go fainter than
that.
At the same time, UT measurements of objects as large as KX76 will sample
the visibility beyond the first minimum, permitting studies on 2nd order
geometrical properties.
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MIDI
overview
Instrument
Overview - MIDI
MIDI
[D/F/NL; PI: Heidelberg]
Paranal: November 2002
First Fringes with UTs: December 2002
Mid IR instrument (10–20 m) , 2-beam, Spectral Resolution: 30-260
Limiting Magnitude N ~ 4 (1.0Jy, UT with tip/tilt, no fringe-tracker) (0.8 AT)
N ~ 9 (10mJ, with fringe-tracker) (5.8 AT)
Visibility Accuracy 1%-5%
Airy Disk
0.26” (UT), 1.14” (AT)
Diffraction Limit [200m]
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0.01”
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AMBER overview
AMBER
[F/D/I;
PI: Nice]
Paranal: January 2003
First Fringes with UTs (AO): July 2003
Near IR Instrument (1–2.5 m) , 3-beam combination (closure phase)
Spectral dispersion: ~35, ~1000, ~10000
Limiting Magnitude K =11 (specification, 5, 100ms self-tracking)
J=19.5, H=20.2, K=20 (goal, FT, AO, PRIMA, 4 hours)
Visibility Accuracy
Airy Disk
1% (specification), 0.01% (goal)
0.03”/0.06” (UT), 0.14”/0.25” (AT) [J/K band respectively]
Diffraction Limit [200m]
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0.001” J, 0.002” K
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MIDI Goals for GTO, first runs
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AMBER Scientific Drivers
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Idiosyncrasies of interferometry
☼ two telescopes do not point as one
☼ night shadows on Paranal
☼ left is right, up is down, 30 = 435 = 254 = 10!
☼ get your dark hours right
☼ magnitudes are not your usual magnitudes
☼ integration time and Earth rotation
☼ living in Fourier space
☼ always shoot in the right spot
☼ calibrate, calibrate, calibrate!
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Interferometry Week, ESO
Santiago 16-01-02
89
Calibrators!
VLTI October 24-25, 2001
Vm,1=  Vo,1
73.0%
Vm,2=  Vo,2
Transfer Function
71.0%
69.0%
Cal 1
Cal 2
Cal 3
Cal 4
67.0%
65.0%
=transfer f.
63.0%
61.0%
6:
41
5:
52
5:
01
4:
34
4:
11
3:
43
2:
55
2:
01
0:
38
59.0%
UT TIME
A. Richichi
Interferometry Week, ESO
Santiago 16-01-02
Aver.
Cal 1 w.m
Cal 2 w.m.
Cal 3
Cal 4 w.m.
67.3%
67.7%
68.6%
65.2%
62.8%
90
2.3%
0.2%
0.2%
0.4%
1.0%
Fringes on the WEB
ESO VLTI:
http://www.hq.eso.org/projects/vlti/
AMBER and MIDI:
http://buz.obs-nice.fr/amber/
http://www.mpia-hd.mpg.de/MIDI/
This presentation:
http://www.eso.org/~arichich/download/iwtutorial/