Tuesday3 February 200412:08am MST 4 Feb.2004-02-04 UTC 0708 back top next  

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


Today's issue status: done
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Today's cover is an Astrometrica screen shot from Robert Hutsebaut's participation yesterday in confirming LINEAR discovery, 2004 BB103, a kilometer-plus object with impact solutions. He was working from Belgium using a Rent-a-scope telescope at New Mexico Skies Observatory, and succeeded despite the bright Moon, "thanks to [Astrometrica author] Herbert Raab's work." The faint object is marked by orange bars, while green circles show the stars used by the software to determine the astrometric position. This stack is made from 12 20-second exposures.

Small objects – part 1/4 Major News for 3 Feb. 2004 back top next  
Small objects  

Discoveries & follow-up 26 Jan. – 1 Feb.

Among the smallest asteroids that come near enough to be noticed and watched, three were discovered and 13 more were tracked last week. This report summarizes that observing activity with objects listed in size order, smallest first. The data is as of Sunday, with H (absolute magnitude) and Earth MOID (minimum orbital intersection) from the JPL NEO Orbital Elements page and other planetary MOIDs 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 an object's discovery MPEC. Diameters are best estimates from a standard but very inexact H-to-size formula. Priorities, visibilities, and campaigns are from European Spaceguard Central Node (SCN).

A/CC has been developing a special focus on the smallest near-Earth asteroids since last September, and has run weekly summaries since December. The last two were for through January 18th and January 25th.

If an asteroid's orbit brings it to within 0.05 AU of Earth's orbit, it is categorized as "potentialy hazardous" unless it has an absolute magnitude H greater than 22.0, which corresponds to a diameter on the order of 135 meters/yards or less. Larger H is dimmer, thus smaller. 0.05 astronomical units (AU) is about 19.5 times the distance between Earth and Moon (0.00256 AU).
2004 BN41   Apollo
Est. diameter: 24 meters/yards
JPL H=25.75   MPC H=26.1 (25.4)
Earth MOID: 0.01001 AU
Has impact solutions
SCN Necessary, vis. ends 9 Feb.
SCN observing campaign
2004 BN41 was reported this last week as observed on 25 Jan. by Great Shefford Obs., on 28 Jan. with the Spacewatch 1.8m telescope, and on 30 Jan. by the Spacewatch 1.8m telescope. 2004 BN41 was discovered on 23 Jan. by LINEAR and was announced in MPEC 2004-B39 of 24 Jan. This object has an MOID of 0.022 AU with Mars.
2004 BV18   Apollo
Est. diameter: 26 meters/yards
JPL H=25.57   MPC H=25.9 (26.1)
Earth MOID: 0.01192 AU
SCN Useful, vis. ends 3 Mar.
2004 BV18 was reported this last week as observed on 27 Jan. by Tenagra II Obs., on 29 Jan. by LINEAR, on 30 Jan. by LINEAR, and on 31 Jan. by Sabino Canyon Obs., LINEAR, Desert Moon Obs., and Tenagra II Obs. 2004 BV18 was discovered on 19 Jan. with the Spacewatch 0.9m telescope and was announced in MPEC 2004-B23 of 20 Jan. This object has an MOID of 0.033 AU with Mars.
Small objects – part 2/4 Major News for 3 Feb. 2004 back top next  
2004 BK86   Apollo
Est. diameter: 27 meters/yards
JPL H=25.46   MPC H=25.4 (24.6)
Earth MOID: 0.00096 AU
SCN Urgent, vis. ends 1 Feb.
NEW: 2004 BK86 was discovered on 27 Jan. with the Spacewatch 0.9m telescope, was confirmed on 28 Jan. with the Spacewatch 1.8m telescope and on 29 Jan. with the Spacewatch 1.8m telescope, and was announced in MPEC 2004-B64 of 29 Jan.
2004 BG41   Apollo
Est. diameter: 36 meters/yards
JPL H=24.89   MPC H=24.9 (24.8)
Earth MOID: 0.01348 AU
SCN Necessary, vis. ends 18 Feb.
2004 BG41 was reported this last week as observed on 28 Jan. by Desert Moon Obs. 2004 BG41 was discovered on 22 Jan. by LINEAR and was announced in MPEC 2004-B36 of 23 Jan.
2004 AD   Apollo
Est. diameter: 43 meters/yards
JPL H=24.49   MPC H=24.4 (24.3)
Earth MOID: 0.02486 AU
SCN Useful, vis. ends 8 Feb.
2004 AD was reported this last week as observed on 11 Jan. by Camarillo Obs. and on 30 Jan. by Jornada Obs. 2004 AD was discovered on 4 Jan. by LONEOS and was announced in MPEC 2004-A23 of 5 Jan.
2004 AE6   Apollo
Est. diameter: 44 meters/yards
JPL H=24.45   MPC H=24.5 (24.7)
Earth MOID: 0.05589 AU
SCN Urgent, vis. ends 18 Feb.
2004 AE6 was reported this last week as observed on 28 Jan. with the Spacewatch 1.8m telescope. 2004 AE6 was discovered on 15 Jan. with the Spacewatch 0.9m telescope and was announced in MPEC 2004-B04 of 17 Jan. This object has an MOID of 0.026 AU with Mars.
2004 BA75   Apollo
Est. diameter: 44 meters/yards
JPL H=24.45   MPC H=24.4 (25.4)
Earth MOID: 0.01342 AU
NEW: 2004 BA75 was discovered on 30 Jan. by LINEAR, was confirmed on 31 Jan. by Catalina Sky Survey (CSS), and was announced in MPEC 2004-B79 of 31 Jan. 2004 BA75 was reported this last week as observed on 30 and 31 Jan. with the Spacewatch 1.8m telescope. This object has MOIDs of 0.023 AU with Venus and 0.019 AU with Mars.
2004 BY1   Aten
Est. diameter: 44 meters/yards
JPL H=24.41   MPC H=24.5 (25.0)
Earth MOID: 0.02118 AU
SCN Necessary, vis. ends 19 Feb.
2004 BY1 was reported this last week as observed on 28 Jan. by Tenagra II Obs. 2004 BY1 was discovered on 17 Jan. by NEAT/Haleakala and was announced in MPEC 2004-B10 of 18 Jan. This object has an MOID of 0.004 AU with Venus.
Small objects – part 3/4 Major News for 3 Feb. 2004 back top next  
2004 BH11   Apollo
Est. diameter: 49 meters/yards
JPL H=24.19   MPC H=24.1 (24.1)
Earth MOID: 0.01722 AU
SCN Necessary, vis. ends 3 Feb.
2004 BH11 was reported this last week as observed on 28 Jan. with the Spacewatch 1.8m telescope. 2004 BH11 was discovered on 18 Jan. with that telescope and announced in MPEC 2004-B17 of 19 Jan.
2004 BF11   Amor
Est. diameter: 51 meters/yards
JPL H=24.11   MPC H=24.1 (24.2)
Earth MOID: 0.14183 AU
SCN Necessary, vis. ends 24 Feb.
2004 BF11 was reported this last week as observed on 28 Jan. with the Spacewatch 1.8m telescope. 2004 BF11 was discovered on 18 Jan. with that telescope and announced in MPEC 2004-B15 of 19 Jan. It has an MOID of 0.047 AU with Mars.
2004 BK11   Amor
Est. diameter: 106 meters/yards
JPL H=22.53   MPC H=22.4 (22.5)
Earth MOID: 0.27748 AU
SCN Necessary, vis. ends 27 Feb.
2004 BK11 was reported this last week as observed on 28 Jan. with the Spacewatch 1.8m telescope. 2004 BK11 was discovered on 18 Jan. with that telescope and announced in MPEC 2004-B19 of 19 Jan.


2004 AD1   Apollo
Est. diameter: 113 meters/yards
JPL H=22.39   MPC H=22.5 (22.5)
Earth MOID: 0.02858 AU
SCN Necessary, vis. ends 17 Feb.
2004 AD1 was reported this last week as observed on 26 Jan. by LONEOS. 2004 AD1 was discovered on 13 Jan. by LONEOS and was announced in MPEC 2004-A53 of 14 Jan.
2004 BB75   Amor
Est. diameter: 108 meters/yards
JPL H=22.48   MPC H=22.9 (22.6)
Earth MOID: 0.03598 AU
SCN Necessary, vis. ends 16 Mar.
NEW: 2004 BB75 was discovered on 28 Jan. by LINEAR, was confirmed on 29 Jan. by Great Shefford Obs. by LONEOS, and was announced in MPEC 2004-B65 of 29 Jan. It was reported this last week as observed on 29 Jan. by LINEAR and on 30 Jan. by Tenagra II. A BB75 image from Great Shefford was the Major News Sunday cover.
2004 BB75 confirmation image stack
from Great Shefford Obs. 29 Jan. 2004
Great Shefford Obs. 2004 BB75 confirmation image.
Small objects – part 4/4 Major News for 3 Feb. 2004 back top next  
2004 BW18 on 29 Jan. 2004 by Pla D'Arguines Obs. 2004 BW18   Amor
Est. diameter: 128 meters/yards
JPL H=22.11   MPC H=22.5 (22.5)
Earth MOID: 0.04561 AU
SCN Useful, vis. ends 28 May
2004 BW18 was reported this last week as observed on 24 Jan. by Modra Obs., on 29 Jan. by Pla D'Arguines Obs. [animation], and on 30 Jan. by LINEAR. 2004 BW18 was discovered on 19 Jan. by LINEAR and announced 20 Jan. in MPEC 2004-B24.
2004 BT58   Aten
Est. diameter: 144 meters/yards
JPL H=21.86   MPC H=22.0 (22.1)
Earth MOID: 0.07794 AU
SCN Necessary, vis. ends 25 Feb.
2004 BT58 was reported this last week as observed on 25 Jan. by Great Shefford Obs., on 27 Jan. by Tenagra II Obs., and on 28 Jan. by Tenagra II Obs. 2004 BT58 was discovered on 23 Jan. by LINEAR and announced 25 Jan. in MPEC 2004-B44. It has an MOID of 0.050 AU with Venus.
Earth's neighborhood on 1 Feb. 2004
ecliptic grid at 20 lunar distances
2004 BM11   Apollo
Est. diameter: 147 meters/yards
JPL H=21.81   MPC H=22.1 (22.2)
Earth MOID: 0.06096 AU
SCN Urgent, vis. ends 6 Feb.
2004 BM11 was reported this last week as observed on 26 Jan. from Mauna Kea and on 28 Jan. by Tenagra II Obs. 2004 BM11 was discovered on 18 Jan. by NEAT/Palomar and announced 19 Jan. in MPEC 2004-B21. It has MOIDs of 0.014 AU with Venus and 0.038 AU with Mars.

Left: Earth's neighborhood on February 1st with known small objects (H>22.0) shown as green dots. The 16 that were reported observed last week are identified with orbit, red circle, and designation. This graphic is made up from two screen shots from the EasySky planetarium software for Windows with the "ecliptic grid" set at 20 lunar distances
News briefs – part 1/1 Major News for 3 Feb. 2004 back top next  
News briefs

Spitzer results:  A "preliminary analysis" of data from January 21st was posted yesterday as a 19Kb PDF "to help observers planning GO-1 observations of asteroids, or observations in the ecliptic plane between -5° to +5° ecliptic latitude." It is a technical document with the title, "The Spitzer Space Telescope First Look Survey — Ecliptic Plane Component Thermal Observations and Preliminary Number Counts."

The First Look Survey (FLS) Ecliptic Component page says:

Our main goal is to characterize the population of moving objects, at 8 and 24 microns, and to explore smaller members of the asteroid population (< 1 km diameter). This survey has been designed to target asteroids in the main belt region between 2 and 4 AU, to determine number counts and ecliptic plane scale heights. With supporting ground-based observations at visible wavelengths we will also provide asteroid sizes and orbits to enable followup observations.

Rosetta:  The European Space Agency (ESA) posted another Rosetta comet mission preview today ahead of the February 26th launch.

[Even] Ariane 5, the most powerful launcher on the market today, lacks the power to hurl the probe on a direct route to the comet. To get the required momentum, it will rely on swing-by manoeuvres, using the gravitation pull of Mars (in 2007) and the Earth (three times, in 2005, 2007 and 2008). 

During the ten years en route, there will be instrument tests, course corrections, and at least one asteroid encounter, but mostly just long silences.

Impact theory:  An Astronomy & Geophysics article and Cardiff University news release at EurekAlert today [see also] revisit the idea that "very cold summers around 536-540 AD" resulted from a comet impact:

The work was carried out by two Cardiff undergraduate students . . . under the supervision of Dr Derek Ward-Thompson [who said it] "shows that even a comet of only half a kilometre in size could have global consequences. Previously nothing less than a kilometre across was counted as a global threat."

UPI has a report today at the Washington Times as "Scientists: Comet caused Dark Age frosts."

Risk monitoring - part 1/2 Major News for 3 Feb. 2004 back top next  
Risk monitoring 3 Feb.

The Tuesday Daily Orbit Update MPEC (DOU) carries observations from LINEAR early yesterday in New Mexico of 2004 BB103, which was posted by NEODyS today and by JPL yesterday. The new data extends the short viewing arc by about 12 minutes, and today JPL very slightly lowered its risk ratings for this kilometer-plus object.

2004 BE68 has observations reported from early Saturday from Tenagra II Observatory in Arizona. This didn't add to the observing arc, but today JPL slightly, and NEODyS very slightly, lowered risk assessments for this object, while the NEODyS impact solution count rose from 44 to 55.

A single position is reported in the DOU from Saturday morning from Linz Observatory in Austria for 2004 BZ74. This didn't extend the viewing arc, but today both risk monitors cut their impact solution counts from 27 to 22 and very slightly raised their risk assessments for this object.

more Risk monitoring >>

Summary Risk Table - sources checked at 0703 UTC, 4 Feb

Object

Assessment

Years

VI
PS
cum
PS
max
T
S
Arc 
days
 2004 BZ74 NEODyS 2/32016-208022-2.65-3.1105.393
JPL 2/32016-209422-2.44-2.7405.393
 2004 BN41JPL 1/312086-20982-6.57-6.6906.998
 2004 BG86 NEODyS 2/12015-207310-4.24-4.6803.006
JPL 1/312015-20151-4.56-4.5603.006
 2004 BE68 NEODyS 2/32008-208055-2.63-3.3305.390
JPL 2/32016-210245-2.69-3.4705.390
 2004 BB103 NEODyS 2/32009-208094-2.40-3.0802.053
JPL 2/32009-2103184-2.08-2.7802.053
 2003 YG118JPL 2/3R E M O V E D
NEODyS 12/31R E M O V E D
VI = count of "virtual impactors" (impact solutions)
See A/CC's Consolidated Risk Tables for more and maybe
  newer details, and check the monitors' links for latest info.
Note that only objects recently in view are shown here.

Today's "Risk monitoring" report narrates routine activity in the night-and-day cycle of observation and analysis that identifies and usually soon removes risk possibilities. There is nothing unusual or alarming here. An "impact solution" (aka "virtual impactor" or "VI") is not a prediction but rather a possibility that hasn't been eliminated yet. To learn more, see "Understanding Risk Pages" by Jon Giorgini of JPL, and other links related to this subject.

Risk monitoring - part 2/2 Major News for 3 Feb. 2004 back top next  

<< continued from part 1

The DOU has a set of LINEAR observations of 2003 YG118 from early yesterday, and today JPL, for the third time since January 2nd, has removed a last single YG118 impact solution.

The European Spaceguard Central Node (SCN) Priority List today removed 2004 BN41 (more info above). Yesterday it had been noted at level 2 Necessary and in view for most observers until February 9th. An SCN observing campaign remains in effect.

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