Suborbital Observations of Meteor Showers

Suborbital observations of meteor showers: finding the parent bodies of our daytime showers Peter Jenniskens1 (1SETI Institute, Mountain View, California, USA; [email protected])

Summary Manned suborbital flights will on occasion observe meteors from daytime meteor showers against a dark sky background all around the spacecraft. This enables optical observations, which can help trace the meteoroids back to their Near Earth Object parent body source, by measuring fundamental physical properties of their matter released as mm-cm sized grains.

Introduction What meteor showers will delight the suborbital researchers who go up to the 80-100 km altitude range where hypervelocity meteoroids flare into bright lights? If the first flights will be daytime flights, that could be daytime meteor showers! When the spacecraft gains altitude, the sky Figure1: November 2010 night-time showers, as darkens. Against this dark daytime sky, meteors measured by CAMS (Jenniskens et al., 2011). can be studied by optical techniques.

Daytime showers and the Daytime zeta Perseids and Daytime beta The International Astronomical Union recognizes 8 Taurids, twins of the night-time Northern and meteor showers that carry the predicate “Daytime” Southern Taurid showers shown in Figure 1. Their (Table 1). These are defined as approaching Earth precise relation and origin (2P/Encke?) remains from a direction within 32º of the Sun. Such unclear at present. At the end of September, the meteoroid streams approach from the Sun, but Daytime Sextantids are strong, originating from light up everywhere around the spacecraft when asteroid 2005 UD and related to asteroid 3200 the Sun is up. Another 34 such showers are in the Phaethon and the Geminids. Not all daytime Working List, awaiting confirmation. showers have a night-time counterpart, notably if the other node is far from Earth orbit. This is more Table 1. Established daytime meteor showers likely for high inclination showers, such as the ones #144 Daytime April Piscids April tracing to potentially hazardous comets. #171 Daytime Arietids June #172 Daytime zeta Perseids June Radars typically do not isolate showers well from #173 Daytime beta Taurids June sporadic meteors and donʼt provide insight into #325 Daytime lambda Taurids June meteoroid elemental composition, contents of #188 Daytime xi Orionids July organic matter, and meteoroid penetration depths, #212 Daytime kappa Leonids September for example. The ability to deploy optical #221 Daytime Sextantids September techniques can provide a new window on the universe around us. These daytime showers are known from radar observations only. Especially the month of June is References known to be an active season, with intense Jenniskens P., et al., 2011. CAMS: Cameras for showers of Daytime Arietids, originating from Allsky Meteor Surveillance to validate minor breakup of the Marsden Sungrazer Comet family, meteor showers. Icarus 216, 40-61.