TPF-I SWG Report - Exoplanet Exploration Program - NASA

More documents

Recommendations

Info

C HAPTER 4 15 10 Response 5 0 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 -5 -10 θ x / μrad 0 ± π/2 ± π ± 3π/2 0.40 1 2 3 4 Beamtrain optics Planet photon rate / s -1 0.30 0.20 0.10 0.00 0 1 2 3 4 5 6 -0.10 -0.20 Single-mode spatial filter -0.30 -0.40 Array rotation angle / radians Figure 4-3. Chopped dual Bracewell configuration. Lower left – schematic of interferometer; upper left – section through response on the sky; upper right – response on sky showing star at central null and planet offset. The planet follows the red locus as the array is rotated about the line of sight to the star; the corresponding photon rate vs. rotation angle is shown at lower right. The lower right panel of Figure 4-3 shows the variation of the chopped planet photon rate with the rotation angle of the array. This characteristic signature depends on the location of the planet relative to the star. As we change the ‘azimuthal’ offset of the planet, the signature pattern is shifted left or right with respect to the array rotation angle. Increasing the radial offset of the planet from the star means that the circular locus in the upper right panel of Figure 4-3 expands and passes through more peaks and valleys of the response, resulting in a signature pattern with higher ‘frequency’. In general, the data must be inverted to obtain the fluxes and locations of any planets that are present. The approach that has been used most commonly to do this is correlation mapping, first suggested by Angel and Woolf (1997). The principle is described in Figure 4-4. The process is closely analogous to the Fourier transform used for standard interferometric image synthesis. The cross-correlation process generates a “dirty map” (a term borrowed from radio synthesis imaging), which must be deconvolved to extract the point-like planets. The example in Figure 4-4 shows the noise-free dirty map for a single point source, and therefore represents the point-spread function (PSF) for the array. Because we are dealing 62
D ESIGN AND A R C H I T E C T U R E T RADE S TUDIES Measured X-Array, 2:1, L = 80 m, λ = 10 μm Template 2 Template 1 Template 3 Template 4 Figure 4-4. Calculation of the cross-correlation map. The measured chopped planet photon rate vs. array rotation angle is shown in the upper left (no noise). For each possible location of a planet in the map, we can generate a template for the signal that would be obtained. This grid of templates is crosscorrelated with the measured signal, and the level of correlation is plotted as the grey-scale. Template 1 would result from a planet in the upper left of the plot. The template is clearly a poor match to the measured signal, and the correlation is low. The highest correlation is obtained with template 2, which corresponds to the actual location of the planet. Template 3 is from a slightly offset location and has reduced correlation. Template 4 is from the opposite side of the star and has a perfect anticorrelation with the measured signal. with a phased array in which more than two collectors are combined in a single output, the PSF is more complex than for a standard imaging array in which each baseline is measured independently. There are satellite peaks in addition to the main peak, each of which has sideobes, and the PSF varies with the position in the map. Section 4.9.2 shows how these properties depend on the array configuration. Approaches to deconvolution are described in Section 4.9.4. Up to this point the analysis has been for a single wavelength. The measurements in practice span a broad range of wavelengths (nominally 6.5–18 μm). Independent of the desire to do spectroscopy, the measurement must be broken out into a number of spectroscopic channels to avoid smearing together the different planet signatures (photon vs. array-rotation angle) obtained at each wavelength. Each of these channels is processed independently to obtain a correlation map. The correlation maps can then be co-added (with appropriate weighting) to obtain the net correlation map. The wide range of wavelengths greatly extends the u-v coverage of the array, suppressing the sidelobes of the PSF. 63
Page 1 and 2:
JPL Publication 07-1 Terrestrial Pl
Page 3:
Abstract Over the past two years, t
Page 7 and 8:
Acknowledgements Twenty-two represe
Page 9 and 10:
Table of Contents 1 Introduction...
Page 11 and 12:
4.8.3 Post-Nulling Calibration.....
Page 13 and 14:
6.4.5 Double Fourier Interferometry
Page 15 and 16:
I NTRODUCTION 1 Introduction Over 2
Page 17 and 18:
I NTRODUCTION et al. 2004), and res
Page 19 and 20:
I NTRODUCTION Standard Interferomet
Page 21:
I NTRODUCTION 1.4 References Angel,
Page 24 and 25:
C HAPTER 2 0.7 to 1.5 AU scaled by
Page 26 and 27: C HAPTER 2 Table 2-2. Illustrative
Page 28 and 29: C HAPTER 2 Classical interferometry
Page 30 and 31: C HAPTER 2 trivial in the absence o
Page 32 and 33: C HAPTER 2 Figure 2-3. Simulated mi
Page 34 and 35: C HAPTER 2 would be in atmospheres
Page 36 and 37: C HAPTER 2 Figure 2-6. The mid-infr
Page 38 and 39: C HAPTER 2 Lines of constant stella
Page 40 and 41: C HAPTER 2 presence of zodiacal clo
Page 42 and 43: C HAPTER 2 S EZ 2π ∫ θ max ∫
Page 44 and 45: C HAPTER 2 Figure 2-11. Observation
Page 46 and 47: C HAPTER 2 Figure 2-12. Models of t
Page 48 and 49: C HAPTER 2 Beichman, C. A., Fridlun
Page 50 and 51: C HAPTER 2 2.7.4 Suitable Targets E
Page 52 and 53: C HAPTER 2 Reach, W. T., Franz, B.
Page 54 and 55: C HAPTER 3 3.1.1 Darwin/TPF-I Prope
Page 56 and 57: C HAPTER 3 clouds or an OB associat
Page 58 and 59: C HAPTER 3 Figure 3-3. Three possib
Page 60 and 61: C HAPTER 3 the circumstellar disk,
Page 62 and 63: C HAPTER 3 Figure 3-6. (Left panel)
Page 64 and 65: C HAPTER 3 Continuum interferometry
Page 66 and 67: C HAPTER 3 Figure 3-9: Simulated im
Page 68 and 69: C HAPTER 3 3.3 Conclusions Darwin/T
Page 70 and 71: C HAPTER 3 Nguyen, H. T., Kallivaya
Page 73 and 74: D ESIGN AND A R C H I T E C T U R E
Page 75: D ESIGN AND A R C H I T E C T U R E
Page 111: D ESIGN AND A R C H I T E C T U R E
Page 114 and 115: C HAPTER 5 Heavy launch vehicle. Th
Page 116 and 117: C HAPTER 5 5.3.2 Combiner Spacecraf
Page 118 and 119: C HAPTER 5 5.3.5 Beam Transfer betw
Page 120 and 121: C HAPTER 5 Figure 5-8. Control sche
Page 122 and 123: C HAPTER 5 Figure 5-9. First sectio
Page 124 and 125: C HAPTER 5 Figure 5-9 shows the fir
Page 126 and 127:
C HAPTER 5 5.4.4 Shear Metrology Sh
Page 128 and 129:
C HAPTER 5 Figure 5-15. TPF-I Fligh
Page 130 and 131:
C HAPTER 5 secondary mirror along t
Page 132 and 133:
C HAPTER 5 a) c) b) d) IWA = 43 mas
Page 134 and 135:
C HAPTER 5 planets found. Figure 5-
Page 136 and 137:
C HAPTER 5 30 25 5 M earth 3 M eart
Page 138 and 139:
C HAPTER 5 5.8.4 Angular Resolution
Page 140 and 141:
C HAPTER 5 Table 5-3. Angular Resol
Page 142 and 143:
C HAPTER 5 The optimization works b
Page 145 and 146:
T E C H N O L O G Y R OADMAP FOR TP
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
F UTURE D EVELOPMENTS 7 Preparatory
Page 175 and 176:
F UTURE D EVELOPMENTS • To comple
Page 177 and 178:
F UTURE D EVELOPMENTS Table 7-1. Pr
Page 179 and 180:
D ISCUSSION AND C ONCLUSION 8 Discu
Page 181 and 182:
Appendices 167
Page 183 and 184:
T E C H N O L O G Y A DVISORY C O M
Page 185 and 186:
F L I G H T S YSTEM C ONFIGURATION
Page 187:
F L I G H T S YSTEM C ONFIGURATION
Page 190 and 191:
A PPENDIX C 2. Identical FACS fligh
Page 192 and 193:
A PPENDIX C 2. Recall that the coef
Page 194 and 195:
A PPENDIX C Once the formation has
Page 196 and 197:
A PPENDIX C Figure C-3. Example of
Page 198 and 199:
A PPENDIX C Figure C-4. FAST Flight
Page 200 and 201:
A PPENDIX C The “true” time of
Page 202 and 203:
A PPENDIX C References Cohen, S., a
Page 204 and 205:
A PPENDIX D DC DCB DM DM DOCS DOD D
Page 206 and 207:
A PPENDIX D NaCl NAR NASA NASTRAN N
Page 208 and 209:
A PPENDIX E Appendix E TPF-I Review
Page 210 and 211:
A PPENDIX F Alice Quillen, Universi
Page 212:
A PPENDIX F Figure 3-1 - Original f
show all

TPF-I SWG Report - Exoplanet Exploration Program - NASA

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?