Contributions to Observations of Near-Earth Objects by a Wide-Field CMOS Camera: Tomo-e Gozen

A presentation material in IAAPDC2017 in Tokyo.

Transcript

1. Contributions to Observations of Near-Earth Objects by a Wide-Field CMOS Camera: Tomo-e Gozen Ryou Ohsawa (Univ. Tokyo) Shigeyuki Sako, Naoto Kobayashi, Mamoru Doi (Univ. Tokyo), Fumihiko Usui (CPS), Jun-ichi Watanabe, Ko Arimatsu (NAOJ), Seitaro Urakawa, Shin-ichiro Okumura (BJSGC), Makoto Yoshikawa (JAXA), and Tomo-e Gozen Development team IAA-PDC-17-02-09 IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15
2. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15
3. Outline IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Introduction: NEO surveys and 20-m class asteroids Tomo-e Gozen: a Wide-Field CMOS mosaic camera Possible contributions by the Tomo-e Gozen 1. 2. 3.
4. an Overview of NEO surveys IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15
5. Annual Detections of NEOs IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 0 5 10 15 20 1995 2000 2005 2010 2015 (×102) Detected NEOs Year all size larger than 140m larger than 1km 0 5 10 15 20 1995 2000 2005 2010 2015 data from cneos.jpl.nasa.gov
6. NEO completeness IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 from the presentation by Alan Harris (2014) 10 15 20 25 30 108 106 104 102 100 102 104 106 108 Detected (2012) Estimated (2012) ~10km ~1km ~0.1km ~0.01km asteroid diam. Absolute Magnitude, H Impact Interval (years) Number of Events, N(>H)
7. NEO completeness IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 from the presentation by Alan Harris (2014) 10 15 20 25 30 108 106 104 102 100 102 104 106 108 Detected (2012) Estimated (2012) ~10km ~1km ~0.1km ~0.01km asteroid diam. Absolute Magnitude, H Impact Interval (years) Number of Events, N(>H) Impactors of Tunguska & Chelyabinsk
8. Tomo-e Gozen IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15
9. Kiso Observatory IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 E 137° 37′42″ .2, N 35° 47′ 38″ .7 Kiso-gun, Nagano, Japan 1-m Schmidt telescope the University of Tokyo, since 1974
10. Kiso Observatory IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 E 137° 37′42″ .2, N 35° 47′ 38″ .7 Kiso-gun, Nagano, Japan 1-m Schmidt telescope the University of Tokyo, since 1974
11. Tomo-e Gozen IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 An overview of the Tomo-e Gozen camera 2K×1K CMOS image sensor by Canon 84 CMOS sensors are tiled over the focal plane covering area ~ 20deg2 moon ~ 9degree
12. Tomo-e Gozen IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 An overview of the Tomo-e Gozen camera Specifications Observatory Kiso Observatory Telescope 1.0-m f/3.1 Schmidt telescope Sensor format 2160×1200pixchip-1 Field of view 39′.7×22′.4 × 84chips Pixel scale 19μm, 1″ .189pix-1 Wavelength 350−700nm (peak at 500nm) Filters optical broadband (transparent) Frame rate 2Hz (max, continuous, full frame) Read noise ~ 1.9e- at 2Hz Dark current ~ 0.1e-sec-1pix-1 at 277K Well depth ~ 6,400e - 5σ lim. mag. ~ 18.5mag. in 0.5sec exposure
13. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Specifications Observatory Kiso Observatory Telescope 1.0-m f/3.1 Schmidt telescope Sensor format 2160×1200pixchip-1 Field of view 39′.7×22′.4 × 8chips Pixel scale 19μm, 1″ .189pix-1 Wavelength 350−700nm (peak at 500nm) Filters optical broadband (transparent) Frame rate 2Hz (max, continuous, full frame) Read noise ~ 1.9e- at 2Hz Dark current ~ 0.1e-sec-1pix-1 at 277K Well depth ~ 6,400e - 5σ lim. mag. ~ 18.5mag. in 0.5sec exposure Prototype of Tomo-e Gozen a prototype of the Tomo-e Gozen mounted on the 1.0-m Schmidt telescope a HDR image of the Orion BN region composed of ~5,000× 0.5s exposures
14. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Specifications Observatory Kiso Observatory Telescope 1.0-m f/3.1 Schmidt telescope Sensor format 2160×1200pixchip-1 Field of view 39′.7×22′.4 × 8chips Pixel scale 19μm, 1″ .189pix-1 Wavelength 350−700nm (peak at 500nm) Filters optical broadband (transparent) Frame rate 2Hz (max, continuous, full frame) Read noise ~ 1.9e- at 2Hz Dark current ~ 0.1e-sec-1pix-1 at 277K Well depth ~ 6,400e - 5σ lim. mag. ~ 18.5mag. in 0.5sec exposure Prototype of Tomo-e Gozen a prototype of the Tomo-e Gozen mounted on the 1.0-m Schmidt telescope a HDR image of the Orion BN region composed of ~5,000× 0.5s exposures
15. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Comparison with other facilities Field of view Telescope Exposure time Lim. magnitude Pixel scale Tomo-e Gozen ~ 20deg2 1.0m Schmidt 0.5−3.0sec ~ 18.5mag. 1″ .1 Pan-STARRS(PS2) 2× 7deg2 2× 1.8m 30sec 22.0mag. 0″ .3 Catalina(CSS) ~ 19deg2 0.7m Schmidt 30sec 19.5mag. 2″ .5 LSST ~ 9.6deg2 8.4m 15sec 24.6mag. 0″ .2
16. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Survey with the Tomo-e Gozen
17. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Survey with the Tomo-e Gozen 6× 0.5s exposures
18. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Survey with the Tomo-e Gozen 6× 0.5s exposures 6× 0.5s exposures
19. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Survey with the Tomo-e Gozen 6× 0.5s exposures 6× 0.5s exposures 6× 0.5s exposures 6× 0.5s exposures 2× 2 dithering
20. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Survey with the Tomo-e Gozen 6× 0.5s exposures 6× 0.5s exposures 6× 0.5s exposures 6× 0.5s exposures 2× 2 dithering
21. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Survey with the Tomo-e Gozen 6× 0.5s exposures 6× 0.5s exposures 6× 0.5s exposures 6× 0.5s exposures 2× 2 dithering ~10,000deg2 sky will be covered in 2hours ~ > 3 images will be taken of each point per night.
22. Detectability of 20m class NEOs IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15
23. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Detactability of 20m class NEOs Detection of 10--50m class NEOs with a 1-m telescope ⇉ the distance to the NEO should be small (d ≪ 1au) d
24. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Detactability of 20m class NEOs Detection of 20m class NEOs with a 1-m telescope ⇉ the distance to the NEO should be small (d ≪ 1au) ⇉ an aparent motion is not negligible mock image A fast-moving object appears as a line segment The surface brightness degraded: "Trail Loss"
25. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Detactability of 20m class NEOs Detection of 20m class NEOs with a 1-m telescope ⇉ the distance to the NEO should be small (d ≪ 1au) ⇉ an aparent motion is not negligible mock image A fast-moving object appears as a line segment The surface brightness degraded: "Trail Loss" Trail Loss effect ∝ tpix /texp
26. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Detactability of 20m class NEOs Detection of 20m class NEOs with a 1-m telescope ⇉ the distance to the NEO should be small (d ≪ 1au) ⇉ an aparent motion is not negligible A fast-moving object appears as a line segment The surface brightness degraded: "Trail Loss" ⇉ detactabilies are estimated: Sun Earth NEO [Lkm] d zero phaseangle, distance d, diameter L Trail Loss effect ∝ tpix /texp
27. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Detactability of 20m class NEOs Detection of 20m class NEOs with a 1-m telescope ⇉ the distance to the NEO should be small (d ≪ 1au) ⇉ an aparent motion is not negligible A fast-moving object appears as a line segment The surface brightness degraded: "Trail Loss" ⇉ detactabilies are estimated: Sun Earth NEO [Lkm] d R V zero phaseangle, distance d, diameter L the relative velocity ~ Keplerian rotation Trail Loss effect ∝ tpix /texp
28. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Detactability of 20m NEOs Detection of 20m class NEOs with a 1-m telescope ⇉ the distance to the NEO should be small (d ≪ 1au) ⇉ an aparent motion is not negligible A fast-moving object appears as a line segment The surface brightness degraded: "Trail Loss" ⇉ detactabilies are estimated: Sun Earth NEO [Lkm] d R V zero phaseangle, distance d, diameter L the relative velocity ~ Keplerian rotation the detection threshold ⇆ S/N ≧ 5 Trail Loss effect ∝ tpix /texp
29. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Detactability of 20m NEOs 10-2 10-1 100 10-3 10-2 10-1 100 Diameter (km) Distance (au) LSST Pan-STARRS Catalina Tomo-e Gozen 10-2 10-1 100 10-3 10-2 10-1 100 Detectable not Detectable degraded by the Trail Loss Results for Albedo = 0.3
30. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Detactability of 20m NEOs 10-2 10-1 100 10-3 10-2 10-1 100 Diameter (km) Distance (au) LSST Pan-STARRS Catalina Tomo-e Gozen 10-2 10-1 100 10-3 10-2 10-1 100 Detectable not Detectable degraded by the Trail Loss Results for Albedo = 0.3
31. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Detactability of 20m NEOs 10-2 10-1 100 10-3 10-2 10-1 100 Diameter (km) Distance (au) LSST Pan-STARRS Catalina Tomo-e Gozen 10-2 10-1 100 10-3 10-2 10-1 100 Detectable not Detectable degraded by the Trail Loss Results for Albedo = 0.3
32. IAA Planetary Defense Conference 2017 in Tokyo, 2017.05.15 Summary Tomo-e Gozen: a wide-field CMOS mosaic camera The next flagship instrument at Kiso Observatory, the University of Tokyo. Equipped with 84 CMOS sensors, covering about 20deg2. The Tomo-e Gozen is able to take images continuously at 2Hz. Optimized for a shallow, high-cadance, and wide-area (~10,000deg2) survey. The Tomo-e Gozen can detect 20m-class asteroids at a distance of ~0.01au. 2013 2014 2015 2016 2017 2018 Sensor Development Sensor Evaluation Camera Design Assembly Observation 8-chip first light 21-chip first light 84-chip first light