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Recent Results from NEOWISE

Explore the recent results and future prospects of the NEOWISE asteroid survey, including data analysis, asteroid families, and potential for restarting the survey. Discover new asteroids and track their movements with the NEOWISE team.

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Recent Results from NEOWISE

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  1. Recent Results from NEOWISE Amy Mainzer JPL

  2. WISE/NEOWISE • WISE • 4 imaging channels covering 3 – 25 mm • 40 cm telescope operating at <17K • Surveyed entire sky 2x • Surveyed from Jan 2010 – Feb 2011 • PI: Ned Wright, UCLA Wide Field Infrared Survey Explorer • NEOWISE • WISE not a dedicated asteroid mission • NEOWISE is Planetary Science-funded enhancement to the main WISE pipeline • Two tasks: • Create archive of individual epoch images + solar system-friendly query tool • Discover new asteroids with WISE • Tracklets delivered to Minor Planet Center within 10 days • WISE Moving Object Pipeline (WMOPS) derived from PS MOPS

  3. NEOWISE Team • PI: Amy Mainzer • James Bauer: JPL/IPAC • Roc Cutri: IPAC • Tommy Grav: PSI • Robert Jedicke: IfA • Joe Masiero: NPP postdoc  JPL staff scientist • Bob McMillan: LPI • Carrie Nugent: NPP postdoc • Rachel Stevenson: NPP postdoc • Dave Tholen: IfA • Russ Walker: MIRA • Ned Wright: UCLA • Students: ~15 so far, including Emily Kramer (UCF), Carrie Nugent (UCLA), Jessica Watkins (UCLA)

  4. 1 YEAR NEOWISE SURVEY Sept. 29, 2010 Lost all 12 mm Sept. 29, 2010 - Feb. 1, 2011 3.4 & 4.6 mm only Aug. 5, 2010 Lost 22 mm • >158,000 asteroids detected • >34,000 new discoveries • ~750 NEOs detected • 135 new discoveries • 150 comets detected • 21 comets discovered NEOs – NEOWISE-discovered NEOs – others’ detected Comets – others’ detected Comets – NEOWISE-discovered All other detected objects

  5. NEOWISE Science Data Analysis • Final release of NEOWISE Post-Cryo survey phase data 5/22/2013 • Rerunning WMOPS at lower SNR • Test runs at SNR=3.5 yielded 20% more detections, each with 2x more detections/object (10 20) • Stacking on all known cataloged objects • Creating catalog of physical properties in PDS

  6. Near-Earth Asteroid Numbers & Sizes • Use well-known sensitivity & uniformity of four band survey to compute total numbers from observed sample • 20,500+/-3000 @ 100m vs. prior estimates of 36,000 – 100,000 • >90% of 1 km and larger NEAs have been discovered: Spaceguard goal • Mainzer et al. 2011 ApJ 743, 156 Shallower slope: -1.32+/-0.14 break

  7. NEOWISE Detections of Small NEOs • Smallest NEOs detected by NEOWISE are 8m in diameter • Detected in band W2 at 3-4 lunar distances from the spacecraft, so similar objects could be detected if WISE is restarted • More in data that haven’t been identified yet • 12 NEOs detected with diameters <25m so far, 7 in band W2, so could be detected with reactivated NEOWISE • 100 additional close-approaching NEOs recovered from NEOWISE data in addition to ~550 published to date; 66 detected in band W2 • Diameters & albedos computed (Mainzer et al. in prep)

  8. Determining Sizes • IR radiometry allows determination of size & albedo, can indicate rapid rotation and/or high thermal inertia 2010 XA11: 10±2 m, 57±25% albedo 2010 GH7: 8±2 m, 11±3% albedo, rapid rotator 2010 FD6: 8±2 m, 55±15% albedo, rapid rotator 2010 TN4: 13±3 m, 12±6% albedo

  9. Asteroid Families • Masiero et al. 2013 ApJ 770, 7 “Asteroid Family Identification using the Hierarchical Clustering Method and WISE/NEOWISE Physical Properties” • Use albedo + velocity cuts in HCM method to identify new families/family members w/ ~120,000 Main Belt Asteroids detected by NEOWISE • Link ~38,300 asteroids into 76 families

  10. Restarting NEOWISE • Possible to restart NEOWISE & resume survey using bands W1 and W2 only (3.4 & 4.6 mm) • No consumables now, but limited lifetime due to orbit precession • Orbital plane drift rate depends on solar activity

  11. Restarting NEOWISE • With baseline cadence, would discover ~50-60 new NEOs/year, 25% of which are PHAs (vs. <10% from ground) • Expect to detect & obtain diameters/albedos for ~2000 NEOs in total after 3 year survey • 3 coorbitals detected by NEOWISE in Post-Cryogenic survey phase, including 2 discoveries: horseshoe + Earth Trojan • Possible to discover more coorbitals & set improved limits on population • Same data delivery policies as before

  12. How Restarting Would Work • Spacecraft currently power-positive but pointing at Earth for half of each orbit • Need to resume zenith pointing & wait for cooldown (3-4 months) • Need ~1-2 months to recalibrate distortion, remap bad pixels, etc. • Possible to alter cadence – might improve NEO detectability

  13. NEOWISE Data Use • Total citation count using NEOWISE data & discoveries up to ~100 refereed publications • Total citation count for WISE ~500 refereed publications • NEOWISE is a synoptic mid-infrared all-sky survey, so its science spans many areas of astrophysics & planetary science: • Asteroids • Meteoritics • Variable stars • Icy bodies in the outer solar system • Distance ladder determinations for cosmology • Human exploration • Supernovae • Pulars • Exoplanets • Black hole accretion disks

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