Ground-Based Observations of NEO Encounters: 1998 QE2 and 2012 DA14 Ground-Based Observations of NEO Encounters: 1998 QE2 and 2012 DA14 Nick Moskovitz NSF Postdoctoral Fellow MIT EAPS Nick Moskovitz NSF Postdoctoral Fellow MIT EAPS 2013 SBAG Washington, DC 11 July, 2013 Collaborators Rick Binzel (MIT) Francesca DeMeo (MIT) David Polishook (MIT) Eileen Ryan (NM Tech) Bill Ryan (NM Tech) Tim Lister (LCOGT) Rick Binzel (MIT) Francesca DeMeo (MIT) David Polishook (MIT) Eileen Ryan (NM Tech) Bill Ryan (NM Tech) Tim Lister (LCOGT) Tom Endicott (UMass) Franck Marchis (SETI) Thomas Augesteijn (NOT) Carl Hergenrother (UA) Bin Yang (IfA) Tom Endicott (UMass) Franck Marchis (SETI) Thomas Augesteijn (NOT) Carl Hergenrother (UA) Bin Yang (IfA) NEO Encounters (JPL Horizons) Moon = AU = 60R Geostationary = 6R Roche Limit = 2-3R Predictable thanks to exponential growth of known objects Catalina, LINEAR, LONEOS, Spacewatch, NEAT, Pan-STARRS (285263) 1998 QE2 Passed at ~0.04 AU or 15x lunar distance on May 31, 2013 Diameter = 2.7km Albedo = 6% (Trilling et al. 2010) Observed by Goldstone and Arecibo Binary (285263) 1998 QE2 Passed at ~0.04 AU or 15x lunar distance on May 31, 2013 Diameter = 2.7km Albedo = 6% (Trilling et al. 2010) Observed by Goldstone and Arecibo Binary Rare spectral type for NEOs = Ch-type Visible: Palomar Hale 200 (Mike Hicks/JPL) Near-IR: IRTF/SpeX RELAB (Pieters & Hiroi 2004) (285263) 1998 QE2 Thermal Emission T max ~ 400 K (285263) 1998 QE2 Opposition-centered Orbital Longitude: (285263) 1998 QE2 Opposition-centered Orbital Longitude: AfternoonMorning (285263) 1998 QE2 Evolution of thermal emission Prograde rotation? Low T High T Pre-opposition Post-opposition May 11 June 2 July 5 May 30 data courtesy of Ellen Howell (Arecibo) and colleagues Vervack, Fernandez, Magri and Nolan May 30 2012 DA14 Discovered Feb. 23, 2012 by La Sagra Sky Survey 40m asteroid passed at ~4R on Feb. 15, 2013 (NASA/JPL, P. Chodas) DA14: Encounter Predictions Change in rotation state Tidal disruption or mass loss Induced seismic shaking (Scheeres et al. 2005) Post-Encounter Rotation Period (hr) (Richardson et al. 1998) Max. Distance Avg. Distance Min. Distance DA14: Spectroscopy Visible spectra: Gemini/GMOS NOT/ALFOSC Linked to CO/CV carbonaceous chondrites or FeO-bearing spinel (CAIs) (Bell 1988; Gaffey et al. 1993; Burbine et al. 2002) (Sunshine et al. 2008) DA14: Rotational light curve Post Flyby Data from: Wise (Israel), VATT (Mt. Graham), Kitt Peak (Arizona), Hereford (Arizona), Shefford (UK), Magdalena Ridge (New Mexico) Tumbling rotation state Light curve fit: P 1 = 6.35 hr P 2 = 8.73 hr DA14: Periodogram Analysis 8.9 hr 6.3 hr Light curve fit: P 1 = 6.35 hr P 2 = 8.73 hr Post Flyby (2013) DA14: Periodogram Analysis Discovery (2012)Pre-Flyby (2013) 5.5 1 hr 4.8 1 hr Post Flyby (2013) 8.9 hr 6.3 hr Light curve fit: P 1 = 6.35 hr P 2 = 8.73 hr 1998 QE DA14 Binary object passed at ~0.04 AU on May 31, 2013 Low-albedo strong thermal emission in near-IR Phase dependent variability 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 Multi-semester ToO program at NASAs IRTF Observe close encounters, TC3-like impactors, very low v objects Rapid response (300 sub- km, low v NEOs NOAO: 24 nights per semester for 3 years Assets: PI: Nicholas Moskovitz (MIT) Gemini-NGemini-S Kitt Peak 4mSOAR 4m LowellCTIO 1.3m UH2.2mMagellan David Trilling (NAU)Cristina Thomas (Goddard)Will Grundy (Lowell) Mark Willman (UH)Eric Christensen (UA)Henry Roe (Lowell) Francesca DeMeo (MIT)David Polishook (MIT)Richard Binzel (MIT) Michael Person (MIT)Michael Busch (NRAO)