RecentResults&from&NEOWISE& · 2013-07-17 · NEOWISE Team • PI: Amy Mainzer • James Bauer:...
Transcript of RecentResults&from&NEOWISE& · 2013-07-17 · NEOWISE Team • PI: Amy Mainzer • James Bauer:...
Recent Results from NEOWISE
Amy Mainzer JPL
WISE • 4 imaging channels covering 3 – 25 µm
• 40 cm telescope opera7ng at <17K • Surveyed en7re 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
WISE/NEOWISE
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)
Aug. 5, 2010 Lost 22 µm
Sept. 29, 2010 Lost all 12 µm
Sept. 29, 2010 -‐ Feb. 1, 2011 3.4 & 4.6 µm only
NEOs – NEOWISE-‐discovered NEOs – others’ detected Comets – others’ detected Comets – NEOWISE-‐discovered All other detected objects
1 YEAR NEOWISE SURVEY
• >158,000 asteroids detected • >34,000 new discoveries • ~750 NEOs detected • 135 new discoveries • 150 comets detected • 21 comets discovered
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 detecbons, each with 2x more detecbons/object (10 20)
• Stacking on all known cataloged objects
• Creabng catalog of physical properbes in PDS
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
break
Shallower slope: -1.32+/-0.14
NEOWISE Detecbons of Small NEOs
• Smallest NEOs detected by NEOWISE are 8m in diameter – Detected in band W2 at 3-‐4 lunar distances from the spacecrah, so similar objects could be detected if WISE is restarted
– More in data that haven’t been idenbfied yet
• 12 NEOs detected with diameters <25m so far, 7 in band W2, so could be detected with reacbvated NEOWISE
• 100 addibonal close-‐approaching NEOs recovered from NEOWISE data in addibon to ~550 published to date; 66 detected in band W2 – Diameters & albedos computed (Mainzer et al. in prep)
Determining Sizes
• IR radiometry allows determinabon of size & albedo, can indicate rapid rotabon and/or high thermal inerba
2010 XA11: 10±2 m, 57±25% albedo
2010 TN4: 13±3 m, 12±6% albedo
2010 GH7: 8±2 m, 11±3% albedo, rapid rotator
2010 FD6: 8±2 m, 55±15% albedo, rapid rotator
Asteroid Families
• Masiero et al. 2013 ApJ 770, 7 “Asteroid Family Idenbficabon using the Hierarchical Clustering Method and WISE/NEOWISE Physical Properbes”
• Use albedo + velocity cuts in HCM method to idenbfy new families/family members w/ ~120,000 Main Belt Asteroids detected by NEOWISE
• Link ~38,300 asteroids into 76 families
Restarbng NEOWISE • Possible to restart NEOWISE & resume survey using bands W1 and W2 only (3.4 &
4.6 µm) • No consumables now, but limited lifebme due to orbit precession
• Orbital plane drih rate depends on solar acbvity
Restarbng 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 aher 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 populabon
• Same data delivery policies as before
How Restarbng Would Work • Spacecrah currently power-‐posibve but poinbng at Earth for half of each orbit
• Need to resume zenith poinbng & wait for cooldown (3-‐4 months)
• Need ~1-‐2 months to recalibrate distorbon, remap bad pixels, etc. • Possible to alter cadence – might improve NEO detectability
NEOWISE Data Use • Total citabon count using NEOWISE data & discoveries up to ~100 refereed
publicabons – Total citabon count for WISE ~500 refereed publicabons
• NEOWISE is a synopbc mid-‐infrared all-‐sky survey, so its science spans many areas of astrophysics & planetary science: – Asteroids – Meteoribcs – Variable stars – Icy bodies in the outer solar system – Distance ladder determinabons for cosmology – Human explorabon – Supernovae – Pulars – Exoplanets – Black hole accrebon disks