Ground-Based Observations of NEO Encounters: 1998 QE2 and 2012 DA14

Ground-Based Observations of NEO

Encounters: 1998 QE2 and 2012

DA14

Ground-Based Observations of NEO

Encounters: 1998 QE2 and 2012

DA14

Nick MoskovitzNSF Postdoctoral FellowMIT EAPS

Nick MoskovitzNSF Postdoctoral FellowMIT EAPS

2013 SBAGWashington, DC

11 July, 2013

CollaboratorsRick 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)

ΔMoon = 0.0025 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 QE2Thermal EmissionTmax ~ 400 K

(285263) 1998 QE2Opposition-centered Orbital Longitude:

☍

(285263) 1998 QE2Opposition-centered Orbital Longitude:

Afternoon Morning

☍

(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)

20 25 30 35 40 45

(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:P1 = 6.35 hrP2 = 8.73 hr

DA14: Periodogram Analysis

8.9 hr6.3 hr

Light curve fit:P1 = 6.35 hrP2 = 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 hr6.3

hr

Light curve fit:P1 = 6.35 hrP2 = 8.73 hr

1998 QE2

2012 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 NASA’s IRTF

‣Observe close encounters, TC3-like impactors, very low Δv objects

‣Rapid response (<48 hours) capability

PI: Nicholas Moskovitz (MIT)

Richard Binzel (MIT), Bobby Bus (UH), Tim Spahr (CfA), Steve Chesley (JPL) Francesca DeMeo (MIT), David Polishook (MIT)

(Polishook et al. 2012)

The Mission Accessible Near-Earth Object Survey (MANOS)

‣ Spectra, light curves, & astrometry for >300 sub-km, low Δv NEOs

‣ NOAO: 24 nights per semester for 3 years

‣ Assets:

PI: Nicholas Moskovitz (MIT)

Gemini-N Gemini-SKitt Peak 4m

SOAR 4m

LowellCTIO 1.3m

UH2.2m Magellan

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)