Near-Earth Asteroid Astrometry with Gaia David BANCELIN IMCCE, - - PowerPoint PPT Presentation
Near-Earth Asteroid Astrometry with Gaia David BANCELIN IMCCE, Paris Observatory GREAT-SSO, Pisa, May 4-6 2011 Outline Gaia Mission Scientific goals Nominal Scanning Law Astrometry for known NEAs Impact on current and long
GREAT-SSO, Pisa, May 4-6 2011
Gaia Mission
Scientific goals Nominal Scanning Law
Astrometry for known NEAs
Impact on current and long term uncertainty Collision probability
Astrometry for unknown NEAs
Alert Mode Combination space/ground-based data
GREAT-SSO, Pisa, May 4-6 2011
Scientific goals
GREAT-SSO, Pisa, May 4-6 2011
Scientific goals
GREAT-SSO, Pisa, May 4-6 2011
Nominal Scanning Law
GREAT-SSO, Pisa, May 4-6 2011 Influence on date of observations Influence on the number of
Statistic of observations
GREAT-SSO, Pisa, May 4-6 2011
PHA (Potentially Hazardous Asteroid) discovered
MOID ≤ 0.05 A.U. and H ≤ 22.0 1213 PHAs known (~ 15% NEAs) and 148 with
Deep close-approach with Earth in 2029 (~ 38 000
Choatic orbit Impact trajectories
GREAT-SSO, Pisa, May 4-6 2011
Gaia observations of Apophis
Inhomogenous size of
sets.
Set with longuest arc
used for simulations.
GREAT-SSO, Pisa, May 4-6 2011
Impact on keplerian elements uncertainty
G.B. Only G.B.+ Gaia Gain σO σO
+ G
σO/σO
+ G
a (A.U.) 1.9E-08 6.8E-11 275 e 6.9E-08 3.9E-09 18 i (°) 1.8E-06 1.2E-07 15 Ω (°) 9.9E-05 2.2E-06 45 ω (°) 9.9E-05 2.3E-06 43 M (°) 7.4E-05 6.5E-07 114
Ground-Based data : Optical
(1366) and Radar (5)
Gaia data : 9 observations with
5 mas accuracy
GREAT-SSO, Pisa, May 4-6 2011
Impact on position uncertainty
GREAT-SSO, Pisa, May 4-6 2011
Impact on 2029 b-plane uncertainty
b-plane uncertainty Nominal Orbit Nominal orbit + Gaia data σξ (km) 10.5 0.3 σζ (km) 87 1.4
3σ ellipse uncertainty in (ξ, ζ) in 2029
b-plane
Primary (✳) and Secondary keyholes at
ascending (◾) and descending (◾) node. With Gaia data Without Gaia data GREAT-SSO, Pisa, May 4-6 2011
Number of alerts expected
Family Number Percentage (%) Amor 379 1.9 Apollo 1313 6.6 Atens 205 1 IEO 24 0.1 PHAs 583 2.9 Total 2614 12.5
GREAT-SSO, Pisa, May 4-6 2011
Statistic on a 20000 synthetic NEAs population
Recovery Strategy
GREAT-SSO, Pisa, May 4-6 2011
Hypothetical Geographos (PHA) detected
(α,δ) prediction
GREAT-SSO, Pisa, May 4-6 2011
12'x12' field of view centered in ML
Combination space and ground-based data
One night observation
GREAT-SSO, Pisa, May 4-6 2011 x
Combination space and ground-based data
GREAT-SSO, Pisa, May 4-6 2011
Good improvement of PHAs orbits (even with faint
Useful data for Earth-impact threat study Necessity of a useful strategy for recovery Necessity of a Follow-up for G.B. observations
GREAT-SSO, Pisa, May 4-6 2011