# (31345) 1998 PG

Discovery and designation LONEOS 19 August 1998 2.8042 AU (419.50 Gm) 1.2262 AU (183.43 Gm) 2.0152 AU 0.3915 2.86 yr 93.233° 6.4941° 222.8° 155.97° 1 125.7425 deg / yr 2.86299 yr (1045.708 d) 900 m (3,000 ft)[2] 2.5162 h[1][3] 0.16[2] 188 K (-85°C) Q 17.3[2]

(31345) 1998 PG is a near-earth object discovered by the LONEOS program on August 3, 1998. It is known to have a moon, S/2001 (31345) 1.[4]

## Status as a Near-Earth Object

1998 PG is classified as an Amor asteroid. It has made multiple close approaches to Earth, with the closest being 35,648,680 kilometres (22,151,060 mi) on 15 October 1978.[1]

## Moon

Table Mountain Observatory, where S/2001 (31345) 1 was discovered.
The 1998 PG system compared to other binary asteroids.

1998 PG has a single moon, S/2001 (31345) 1. The moon was discovered at the Table Mountain Observatory by analyzing observations from 29 August to 25 October 1998. S/2001 (31345) 1 has a size of 300 metres (980 ft), one-third the size of the asteroid itself, and orbits every 14 hours with a semi-major axis of 1.5 kilometres (0.93 mi).[2] From the surface of 1998 PG, the moon would have an angular diameter of about 16.3°.[a] For comparison, the Sun appears to be 0.5° from Earth.

## Notes

1. ^ Calculated by solving $\scriptstyle{\mathrm{tan}\left(\frac{\theta}{2}\right) = \frac{\mathrm{radius~of~moon}}{\mathrm{distance~from~surface~of~asteroid~to~center~of~moon}}}$.

## References

1. ^ a b c
2. ^ a b c d Johnston, W. R. (1 September 2005). "(31345) 1998 PG". Johnston's Archive. Retrieved 2013-09-20.
3. ^ Pravec, P. et al. (2000). "Two-Period Lightcurves of 1996 FG3, 1998 PG, and (5407) 1992 AX: One Probable and Two Possible Binary Asteroids". Icarus 146 (1): 190–200. Bibcode:2000Icar..146..190P. doi:10.1006/icar.2000.6375.
4. ^ Lance, B. (6 August 2013). "Binary and Ternary Near-Earth Asteroids Detected by Radar". JPL/NASA. Retrieved 2013-09-20.