Input of natural extraterrestrial material into our atmosphere
Meteors!
Perseid Meteor Shower 2023 ( youtube @MagicCarpetMedia )
Meteors!
- Cover the basics of natural input & meteors
(broad, interdisciplinary, ...) - If I didn't cover your question: ask us later!
This presentation
Perseid Meteor Shower 2023 ( youtube @MagicCarpetMedia )
Meteors!
Where do meteoroids come from?
Rosetta OSIRIS - 67P/Churyumov-Gerasimenko
- Comet sublimation
- Asteroid collision
- Catastrophic disruption
- Dynamical perturbation
- Impact ejecta
- Interstellar?
- ...
Meteoroid streams and meteor showers
Credit: www.meteorshowers.org
Meteors!
Where do meteoroids come from?
Meteors!
Where do meteoroids come from?
- (Jacchia et al. 1967):
99% photographic - (Starczewski & Jopek 2004):
22% radio, 52% photographic, 47% video - (Jopek & Williams 2013):
67% all
Observed cometary sporadics:
No dynamics, instrumental bias, ...
Meteors!
Where do meteoroids come from?
- (Ye 2018) IAU established showers
~87% cometary
Observed streams:
History of "asteroids" -> comet activity
Meteors!
Where do meteoroids come from?
- (Ceplecha et al. 1998)
< 25% visual streams - (Brown et al. 2007)
< 10% radar streams - (Jenniskens et al. 2015)
26% optical streams
Observed Streams vs Sporadic:
Sporadic dominates
The making of a meteor
The making of a meteor
Dyrud et al. 2008
John Plane, 2012
The measurement of a meteor
Meteors and space objects
- (Drolshagen et al. 2007)
$30 - 180 t d^{-1}$
Best guess: $32 - 54 t d^{-1}$ - (Carrillo-Sánchez et al. 2020)
$28 \pm 16 t d^{-1}$
Mass influx estimates:
Background credits: NASA/Reid Wiseman
John's legendary table
John Plane, "Cosmic dust in the earth's atmosphere", 2012
Background credits: NASA/Reid Wiseman
Radar meteor head echoes
Shigaraki Middle and Upper Atmosphere (MU) radar, Japan
Radar & optical meteor distributions
MU radar in Japan
Kastinen & Kero 2022
EMCCD optical system in Ontario, Canada
Mills et al. 2021
Meteoroids/asteroids that survive atmospheric entry?
Video: Chelyabinsk superbolide - Dash-cam footage February 15th 2013
Meteorites
UK Polar Meteorite Exploration and Research, Image by K Joy
Meteorites
UK Polar Meteorite Exploration and Research, Image by K Joy
- Many types:
stony, stony-iron, and iron meteorites
Chondrites, achondrites, pallasites, mesosiderite, ... - (Schulz & Glassmeier 2021)
Meteorites + in-situ collected dust + ...
$\approx$ metal (31%), metalloid (13%), nonmetallic (47%), other (8%)
Tricky: meteorite bias, discovery bias, influx origin, ...
Synergies
- Same instrumentation for re-entry and meteors
- In principle same governing dynamics and ablation physics
but different population characteristics - Different composition & origin (sometimes known!)
Future work
- Fitting ablation to data is currently underdetermined
- More meteorites with known orbits
- Reconcile and improve total mass input estimates
- -> Imrpove observations!
- Improve meteoroid source models
- ...
Video: AMS226 @ IRF roof - DK
Thank you for listening!
Video: AMS226 @ IRF roof - DK
Meteor cameras
Estimating mass
$$ \frac{1}{2}\pi R^2 \rho_a v^3 \Lambda = 4 \pi R^2 \sigma \epsilon ( T_s^4 - T_a^4) + \frac{4}{3}\pi R^3 \rho_m C \frac{dT_m}{dt} + L \frac{dm}{dt} \\ \frac{dv}{dt} = -\frac{\Gamma \rho_a \pi R^2 v^2}{m} $$- Atmosphere: density ${\color{8888FF}\rho_a}$, temperature ${\color{8888FF}T_a}$
- Meteoroid state: velocity ${\color{green}v}$, surface and mean temperature ${\color{green}T_s, T_m}$
- Meteoroid properties: radius ${\color{red}R}$, density ${\color{red}\rho_m}$, specific heat ${\color{red}C}$, head of vaporization ${\color{red}L}$, emissivity ${\color{red}\epsilon}$, drag parameter ${\color{red}\Gamma}$, mass ${\color{red}m}$
Single body, homogenous, spherical, ...