Sky & Telescope - December 2024 - 17

All the red lines are from atmospheric nitrogen and
oxygen and are complex, multiple lines and bands
Na
Fe
Mg (close triplet)
O
N/O
O
Unresolved
iron lines
Iron
lines
Iron
lines
METEOR MAKEUP From top to bottom, these colorized spectra show
the compositional differences of Leonid, Geminid, and iron meteoroids.
The top two spectra span the near-ultraviolet to the near-infrared (380 nm
to 883 nm); their colors are scaled here to include the wavelengths
outside our visible range. Note that this Geminid fireball shows sodium,
which often isn't the case. The iron meteoroid spectrum spans 380 nm to
551 nm and is higher resolution. Nearly every line there is from iron.
altitudes when they arrive in October - an indication that
they are very fragile, because they break up even before diving
into the denser part of Earth's atmosphere. Meteoroids from
comets generally burn up at higher altitudes than those from
asteroids, because they're less sturdy, but the Draconids are
particularly delicate.
By combining multi-station camera data with aerodynamic
models, astronomers can precisely measure the height
and mechanical strength of these meteoroids. The results
show that they can be weaker even than fresh snow! Datamodeling
efforts like this one are becoming increasingly
important, as they allow us to assess certain cometary (and
sometimes, asteroidal) materials without expensive samplereturn
missions (S&T: July 2024, p. 20).
Looking Ahead
Meteor observations effectively use the whole atmosphere
as the detector, and hence meteor science heavily relies on
crowd sourcing the data from observers all over the world. As
such, meteor science is one of the areas where contributions
from citizen scientists remain crucial.
For many years, visual observation has been an important
data source for meteor research. It requires no more than
a pencil and a piece of paper (and preferably an armchair).
Observers still submit their counting data and fireball sightings
to the International Meteor Organization (IMO; imo.net)
and the American Meteor Society (AMS; amsmeteors.org).
On another front, the miniaturization of cameras and
computers in the last decade has helped the rise of digital
surveillance networks. The Global Meteor Network (GMN;
globalmeteornetwork.org), for example, has developed a
low-cost, open-source system based on commercially available
CMOS cameras and Raspberry Pi computers. The GMN
has deployed over 1,200 cameras worldwide. Such efforts have
been crucial in revealing many transient meteor outbursts
that would be missed in the old days and in refining the
structures of known meteor showers.
Meteor astronomy, and our understanding of the solar
system as a whole, will also benefit from the large, next-generation
ground- and space-based telescopes. Surveys such as
the Vera C. Rubin Observatory's Legacy Survey of Space and
Time and NASA's upcoming Near-Earth Object Surveyor mission
will map the solar system with unprecedented sensitivity,
likely finding many meteor-shower parents in the process
(S&T: June 2024, p. 34). Multi-purpose facilities such as the
James Webb Space Telescope and the Atacama Large Millimeter/submillimeter
Array will enable targeted observations of
comets and asteroids with unparalleled sensitivity and spectral
coverage. By combining knowledge on all fronts, we will
deepen our understanding of comets and asteroids as well as
the role that they play in the evolution of our solar system.
The advancement of planetary science and interplanetary
exploration has taken meteor research out of our world, too.
The impact hazard from meteoroids is a legitimate concern
for human spaceflight and robotic spacecraft near and far.
Research on this topic also provides valuable information
about dust's distribution throughout the solar system.
In late 2014, for example, Comet C/2013 A1 Siding Spring
flew close past Mars - whizzing only a third of the EarthMoon
distance away from the Red Planet. The flyby brought
an intense meteor shower to the planet, an event that was
well captured by a fleet of orbiters at Mars and told us a lot
about the comet itself as well as the planet's atmosphere and
magnetic environment.
More broadly, known and unknown meteoroid streams
would bring meteor showers to any planets and moons with
an atmosphere that intercept the meteoroids' orbits, although
none of these has been directly observed yet elsewhere in the
solar system. But we can expect that future orbiters, landers,
rovers, and even human explorers will one day observe shooting
stars on another planet or moon just like we do on Earth,
and appreciate the rich information that they bring to us.
¢ QUANZHI YE is a planetary astronomer at the University
of Maryland and Boston University. He still enjoys going out
stargazing when he is not doing his day (night) job.
sk yand tele scope .o r g * DECEMBER 2024 17
DR. BILL WARD / INTERNATIONAL METEOR ORGANISATION / UNIV. OF THE WEST OF SCOTLAND
http://www.imo.net http://www.amsmeteors.org http://www.globalmeteornetwork.org http://www.skyandtelescope.org
Sky & Telescope - December 2024

Table of Contents for the Digital Edition of Sky & Telescope - December 2024
