The Asteroid/Comet Connection's
daily news journal about
asteroids, comets, and meteors

Today's issue status: done

• Small objects – report for 2-8 February
• Not-so-small objects – 2004 results to date
• News briefs – asteroid taxonomy & Hubble news
• Risk monitoring

Cover image: See below for more about 2004 CC, which was the only newly found small object (H>22.0) announced last week. Robert Hutsebaut's image from Thursday is a stack of three frames centered on the motion of this fast, faint object. Background stars appear as three beads.

Discovery & follow-up 2-8 February

With the full Moon, this last week was a wash for observing the smallest near-Earth asteroids, especially when compared with the previous week and

the week before that. 2004 CC was the only new small object discovered, and tomorrow it will fly past Earth at about 13.8 lunar distances (0.0356 AU).

This report summarizes this observing activity

more about Small objects >>

<< continued from part 1

with objects listed in size order, smallest first. H (absolute magnitude) and Earth MOID (minimum orbital intersection) are from the JPL NEO Orbital Elements page, and other planetary MOIDs are from Lowell Observatory. Earth MOIDs that would be considered hazardous if for larger objects are flagged in yellow. Current Minor Planet Center H is also given, along with the original H from each object's discovery MPEC. Diameters are best estimates from a standard but very inexact H-to-size formula. Priorities, visibilities, and campaigns are from the European Spaceguard Central Node (SCN).

Missing from the week were observations of 2004 BN41 (H=25.75), an object with impact solutions that SCN had noted as going out of view for most observers tomorrow — February 9th — before removing it from its Priority List on the 3rd. It was last seen January 30th after seven days of observation, and has been near the bright Moon since.

Six discoveries in 2004's first five weeks

The current main goal of NEO surveys is to catalog kilometer-plus near-Earth objects (NEOs). The first such object of the year, 2004 AF, was discovered January 5th and announced the next day, and was listed with impact solutions from then until the 9th. It is still the largest NEO found this year, based on JPL's absolute magnitude calculation of H=16.07, which converts by standard formula to a rough best estimate of 2.07 km. (1.28 miles) wide.

Another comparable object wasn't found for two more weeks, until 2004 BO41 was discovered on January 19th but wasn't confirmed until January 23rd and 24th, when it was announced. After further observing, JPL posted a single impact solution on January 26th for BO41, and removed it three days later with the next observations. This object had been announced with H=16.8, but today JPL has it at 17.19 — roughly 1.23 km. (0.77 mile) wide.

2004 BE85 and BV102 were discovered on January 28th and 31st and announced on January 30th and February 1st, respectively. At H=17.63 and 17.29, they are estimated to be in the range of 1.0 to 1.2 km. (0.62-0.73 mile) in diameter.

Neither of those two has been listed with impact solutions, but the next discovery, 2004 BB103, had solutions until yesterday. It was discovered at about the same time as 2004 BV102 on the 31st, and was announced on February 2nd. (2004 BB103 was on the Major News cover for February 3rd.)

Like the other five objects, the latest in this category, 2004 CB, was discovered by LINEAR in New Mexico. It was first spotted on Tuesday and announced Thursday. Originally put at H=18.0, it appears now to be about the same size as 2004 BB103 (H=16.77 vs. 16.81 for BB103), on the order of 1.48 km. (0.92 mile) wide. 2004 CB presently has impact solutions (see "Risk monitoring" below), and Lowell Observatory shows that it can come within 0.554 AU of Jupiter.

Hubble:  Reuters UK has a story today, "NASA Engineers Dispute Decision to Ax Hubble." It says that "two reports . . . written by NASA engineers who feared they would lose their jobs if their names were made public. . . . maintain it is no riskier to service the orbiting telescope than to use shuttle astronauts to finish building the International Space Station." Keith Cowing today posted those two documents on SpaceRef.com.

The Tucson Arizona Daily Star has an article today, "New space scope may lay ancient questions to rest," about the NASA James Webb Space Telescope (JWST), future successor to the Hubble and Spitzer space telescopes. It explains why and how it will view only in the infrared spectrum, and tells about the University of Arizona's involvement. With a 6.5m primary mirror, it will have resolution equivalent to distinguishing "a soccer ball 340 miles away," and will be able to detect infrared radiation from "an ice cube and objects much colder than that."

Asteroid taxonomy:  Gerard Faure has informed the Minor Planet Mailing list (MPML) that a number of changes were needed in his "Description of the System of Asteroids," which was recently revised to incorporate 2003 results, so new French and English versions have now been posted. The previous links are now obsolete, and have been updated in A/CC's original news item

Risk monitoring 8 Feb.

The Sunday Daily Orbit Update MPEC carries observations of 2004 CB from Tenagra II Observatory in Arizona yesterday morning, and early today from Great Shefford Observatory in England. NEODyS and JPL today updated their risk assessments for this object, cutting their impact solution counts and slightly lowering their overall risk assessments for this object estimated at a kilometer and a half wide.