Observations of NEO Encounters: 1998 QE 2 and 2012 DA 14 Nick Moskovitz NSF Postdoctoral Fellow MIT EAPS 2013 SBAG Washington, DC 11 July, 2013
Collaborators Rick Binzel (MIT) Francesca De. Meo (MIT) Tom Endicott (UMass) Franck Marchis (SETI) Thomas Augesteijn David Polishook (MIT) (NOT) Eileen Ryan (NM Carl Hergenrother (UA) Tech) Bin Yang (If. A) Bill Ryan (NM Tech) Tim Lister (LCOGT)
NEO Encounters Predictable thanks to exponential growth of known objects → Catalina, LINEAR, LONEOS, Spacewatch, NEAT, Pan-STARRS ΔMoon = 0. 0025 AU = 60 R♁ Geostationary = 6 R♁ Roche Limit = 2 -3 R♁ (JPL Horizons)
(285263) 1998 QE 2 ‣ Passed at ~0. 04 AU or 15 x lunar distance on May 31, 2013 ‣ Diameter = 2. 7 km Albedo = 6% (Trilling et al. 2010) ‣ Observed by Goldstone and Arecibo → Binary
(285263) 1998 QE 2 ‣ Passed at ~0. 04 AU or 15 x lunar distance on May 31, 2013 ‣ Diameter = 2. 7 km Albedo = 6% (Trilling et al. 2010) ‣ Observed by Goldstone and Arecibo → Binary ‣ Rare spectral type for NEOs = Ch-type RELAB (Pieters & Hiroi 2004) Visible: Palomar Hale 200” (Mike Hicks/JPL) Near-IR: IRTF/Spe. X
(285263) 1998 QE 2 Thermal Emission Tmax ~ 400 K
(285263) 1998 QE 2 Opposition-centered Orbital Longitude: ☍
(285263) 1998 QE 2 Opposition-centered Orbital Longitude: ☍ Afternoon Morning
(285263) 1998 QE 2 ‣ Evolution of thermal emission → Prograde rotation? Low T Pre-opposition May 30 June 2 July 5 Post-opposition High T May 11 May 30 data courtesy of Ellen Howell (Arecibo) and colleagues Vervack, Fernandez, Magri and Nolan
2012 DA 14 ‣ Discovered Feb. 23, 2012 by La Sagra Sky Survey ‣ 40 m asteroid passed at ~4 R♁ on Feb. 15, 2013 (NASA/JPL, P. Chodas)
DA 14: Encounter Predictions ‣ Change in rotation state ‣ Tidal disruption or mass loss Induced seismic shaking ‣ (Richardson et al. 1998) Max. Distance Avg. Distance Min. Distance 20 25 30 35 40 45 Post-Encounter Rotation Period (hr) (Scheeres et al. 200
DA 14: Spectroscopy Visible spectra: Gemini/GMOS NOT/ALFOSC (Bell ‣ Linked to CO/CV carbonaceous chondrites 1988; Gaffey et al. 1993; Burbine et al. 2002) or Fe. O-bearing spinel (CAIs) (Sunshine et al. 2008) ‣
DA 14: Rotational light Data from: Wise (Israel), VATT (Mt. Graham), Kitt Peak curve (Arizona), • Hereford (Arizona), Shefford (UK), Magdalena Ridge (New Mexico) • Tumbling rotation state Post Flyby Light curve fit: P 1 = 6. 35 hr P 2 = 8. 73 hr
DA 14: Periodogram Analysis Post Flyby (2013) 6. 3 hr 8. 9 hr Light curve fit: P 1 = 6. 35 hr P 2 = 8. 73 hr
DA 14: Periodogram Analysis Post Flyby (2013) 6. 3 hr Discovery (2012) 5. 5 ± 1 hr Light curve fit: P 1 = 6. 35 hr P 2 = 8. 73 hr 8. 9 hr Pre-Flyby (2013) 4. 8 ± 1 hr
1998 QE 2 ‣ Binary object passed at ~0. 04 AU on May 31, 2013 ‣ Low-albedo → strong thermal emission in near-IR ‣ Phase dependent variability 2012 DA 14 ‣ Passed at 4 Earth-radii on February 15, 2013 ‣ No clear evidence for spectroscopic changes ‣ Possible suggestion of change in rotation state
IRTF NEO Rapid Response: Close Encounters of the Asteroid Kind PI: Nicholas Moskovitz (MIT) Richard Binzel (MIT), Bobby Bus (UH), Tim Spahr (Cf. A), Steve Chesley (JPL) Francesca De. Meo (MIT), David Polishook (MIT) ‣ Multi-semester To. O program at NASA’s IRTF ‣ Observe close encounters, TC 3 -like impactors, very low Δv objects ‣ Rapid response (<48 hours) capability (Polishook et al. 2012)
The Mission Accessible Near-Earth Object PI: Nicholas Moskovitz Survey (MANOS) (MIT) David Trilling (NAU) Mark Willman (UH) Francesca De. Meo (MIT) Michael Person (MIT) Will Grundy Cristina Thomas (Goddard) (Lowell) Eric Christensen (UA) Henry Roe (Lowell) Richard Binzel David Polishook (MIT) Michael Busch (NRAO) Spectra, light curves, & astrometry for >300 subkm, low Δv NEOs ‣ NOAO: 24 nights per semester for 3 years ‣ Assets: Gemini-N Gemini-S Kitt Peak SOAR 4 m 4 m Lowell CTIO 1. 3 m UH 2. 2 m Magellan ‣
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