Single grain noble gas analysis of Antarctic micrometeorites by stepwise heating method with a newly constructed miniature furnace

Earth, Planets and Space

Table 5. Temperatures for 50% release of ⁴He and estimated velocities.

Sample No.	Diameter d′ (μm)	Weight μg	Density ρ′ (g/cm³)	Diameter ¹⁾d (μm)	Temperature ²⁾ °C	Entry velocity km/s
D03IB05	105	0.83	1.35	71	>800		³⁾
D03IB10	97	0.33	0.69	34	>800		³⁾
D03IB18	92	0.26	0.64	29	>800		³⁾
D03IB19	106	0.14	0.22	12	680	12
D03IB45	120	0.48	0.53	32	>800		³⁾
D05IB20	76	0.42	1.83	69	500	< 10
D05IB27	245	18.49	2.40	294	> 800		³⁾
D05IB74	124	1.03	1.03	64	500	< 10

1) Calculated diameter equivalent to a spherical particle with density 2.0 g/cm³.
2) Temperature for 50% release of ⁴He shown in Fie. 11.
3) Out of the simulated range in Love and Brownlee (1994).