Catching up on the last week in comet and asteroid discoveries… A week ago new NEA announcements were coming left and right but the flood completely stopped a few days before Full Moon. Most surveys take a break for a few days around Full Moon since the bright sky is really not conducive for finding much of anything.
Last week saw one and probably two comet discoveries. C/2010 S1 (LINEAR) is a large perihelion (q = 4.4 AU) long-period comet. Currently 17th magnitude and 8.5 AU from the Sun (almost the distance of Saturn), it should brighten to magnitude 12-13 near perihelion in the summer of 2013. This comet marks the 44th (non-SOHO-STEREO) comet discovery of the year and LINEAR’s 199th comet find.
2010 BK118 was first seen back in January by the WISE (Wide Infrared Space Explorer) spacecraft. WISE is conducting a survey of the sky at 4 infrared wavelengths. Though not specifically designed to find asteroids/comets, the spacecraft observes at wavelengths optimal for finding these types of objects. Though not identified as anything special back in January, it was independently rediscovered by LINEAR last week. After a few days of observation, January’s WISE object and this month’s LINEAR object were linked as one and the same. So far there have been no reports of cometary activity even though the orbit is very cometary (long-period type). If it is truly a extinct or dormant comet than it is very large for a comet nucleus at H = 10.2 and a diameter of ~60 km. I’d be very surprised if this object doesn’t turn out to be an actual comet when larger telescopes are pointed its way.
2010 SW3 passed within 0.0058 AU of Earth on Sept. 10. This distance equals 540,000 miles, 860,000 km or 2.1 Lunar Distances. The 10 to 30 meter in diameter rock was discovered by the Mount Lemmon Survey eight days after close approach.
Asteroid Type MOID a e i H Mag Discoverer MPEC 2010 SE12 Amor 0.115 1.36 0.18 9.3 24.3 20 Spacewatch 2010-S34 2010 SD12 Amor 0.076 1.80 0.41 23.6 23.8 20 Mount Lemmon 2010-S33 2010 SA12 Amor 0.147 2.25 0.50 6.2 20.8 20 Mount Lemmon 2010-S32 2010 SX11 Apollo 0.026 1.16 0.25 5.3 24.8 20 Spacewatch 2010-S30 2010 SZ3 Apollo 0.014 1.18 0.14 2.0 28.3 20 Mount Lemmon 2010-S26 2010 SY3 Amor 0.224 2.08 0.41 6.0 22.8 21 Mount Lemmon 2010-S25 2010 SX3 Amor 0.066 1.59 0.33 8.0 24.9 20 Mount Lemmon 2010-S24 2010 SW3 Apollo 0.0005 1.62 0.40 1.6 26.6 20 Mount Lemmon 2010-S23 2010 SV3 Apollo 0.056 1.51 0.52 6.2 20.5 19 Catalina 2010-S21 2010 ST3 Apollo 0.040 2.06 0.53 3.8 25.1 21 PanSTARRS 2010-S20 2010 SS3 Amor 0.393 1.61 0.24 26.9 20.8 21 Mount Lemmon 2010-S19 2010 SR3 Amor 0.187 1.74 0.37 12.2 21.8 21 Mount Lemmon 2010-S18 2010 SP3 Apollo 0.004 1.98 0.63 0.4 24.6 18 Catalina 2010-S16 2010 RG137 Amor 0.105 2.36 0.55 9.9 21.0 19 Mount Lemmon 2010-S15 Comet Type T q a e i Mag Period MPEC C/2010 S1 (LINEAR) LPC 2013-05-09 4.41 1.0 126.9 17 2010-S41 2010 BK118 (discovered by WISE, rediscovered by LINEAR) ECC 2010-01-01 6.12 293.7 0.98 143.9 19 5030 2010-S36 Type Aten - Earth crossing with semi-major axis (avg distance from Sun) < 1 AU Apollo - Earth crossing with semi-major axis (avg distance from Sun) > 1 AU Amor - non-Earth crossing with perihelion distance < 1.3 AU JFC - Jupiter family comet HFC - Halley family comet LPC - Long-period comet MBC - Main belt comet ECC - Suspected extinct or dormant (or just unrecognized) comet T - Date of Perihelion MOID - Minimum Orbit Intercept Distance, minimum distance between asteroid and Earth's orbit a - semi-major axis, average distance from Sun in AU (1 AU = 93 million miles) e - eccentricity i - inclination H - absolute magnitude Mag - magnitude at discovery Discoverer - survey or person who discovered the object MPEC - Minor Planet Electronic Circular, the discovery announcement
The Transient Sky - Comets, Asteroids, Meteors 
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