CRT Archive for Objects Discovered in 2004 & Earlier

Current assessments:  NEODyS [backup] & JPL NEOPO

Diameter:  580 meters (JPL estimate)

JPL:  Orbit Viewer     NEODyS:  object home page [backup] & observations [backup]

Packed designation:  E4898 (originally K04V17D)

Circulars:  MPECs 2004-V40 & 2005-V96

  [jump to assessment tables]

Notes:  2004 VD17 was discovered on 7 Nov. 2004 by LINEAR in New Mexico and was announced the next day. It was posted with impact solutions at JPL and NEODyS on 9 Nov. when further observations became available. JPL elevated 2004 VD17 to Torino Scale 1 (a routine alert that an object "merits special monitoring") on 22 Nov., and NEODyS put it at TS-1 on the 23rd.

2004 VD17 had been noted to go out of view on 5 Feb. 2005 and wasn't observed after 28 Jan. until David Tholen's team picked it up from Mauna Kea on March 4th, which was published 13 days later.

On 15 Nov. 2005 it was reported that Tholen's team had recovered 2004 VD17 on the 4th, 11th, and 13th of that month using the University of Hawaii 2.2m telescope on Mauna Kea. This more than tripled the object's observation arc, from 117 to 371 days.

2004 VD17 brightened into view in early Feb. 2006 and was picked up with the Spacewatch 1.8m telescope on 6 Feb. It remains in view until around June 22nd, then comes back again in late July for the rest of the year.

On 6 Feb. 2006, for only the second time in risk monitoring history, 2004 VD17 was raised to a Torino Scale rating of 2 (for "a somewhat close but not highly unusual pass near the Earth ... an actual collision is very unlikely"). JPL raised it to TS-2 after the next observations became available on Feb. 23rd.

The DOU MPEC of 12 March 2006 reported three positions from Sergio Foglia, Giuseppe Forti, and Maura Tombelli using archive images from NEAT's Mt. Palomar telescope from 16 Feb. 2002, tripling 2004 VD17's observation arc from 487 to 1,482 days. This data was supplanted in the next DOU MPEC with two positions calculated from the 16 Feb. 2002 archive images, and three positions were added from 14-15 March 2002, all coded as "very faint images." This new data was submitted to the MPC by Rob Matson, who told A/CC that, even though "these five points are pretty self-consistent," they are "basically at the noise floor" for NEAT/Palomar images. Subsequently, the original uncompressed archive images were provided to Matson and Foglia by NEAT to attempt a sure precovery. NEODyS and JPL updated on Matson's data on March 21st, and the new positions were published by the MPC on March 22nd.

On 22-23 May 2006 JPL and NEODyS brought 2004 VD17 back down to Torino Scale 1.

About astrometry, the European Spaceguard Central Node (SCN) first page stated on May 15th, "observations needed with a large telescope (higher astrometric accuracy) in May and June 2016."

2004 VD17 was out of view for ground-based optical telescopes from about June 23rd until around Aug. 5th, and after May was next reported observed in late September, from Catalina Station in Arizona. On 17 Oct. 2006 NEODyS and JPL lowered their Torino Scale ratings for 2004 VD17 to zero ("likelihood of collision is zero, or so low as to be effectively zero") after observation was reported from June 1st. That was from the Spacewatch 1.8m telescope in Arizona, which then went on to report observations from 18, 27, and 28 Oct. NEODyS and JPL on Oct. 29th removed the last single impact solution each had for this object, but posted solutions again a day later.

On 12 Dec. 2006 this object was numbered and is now identified as 144898 2004 VD17, which in formatted MPECs appears as "packed number" E4898.

Magdalena Ridge Observatory (MRO) observed 144898 2004 VD17 on 13 Feb. 2008, following which JPL removed its last impact solution for this object and NEODyS updated its risk assessment.

[ 2004 VD17 top | page top ]

Current assessment:  NEODyS [backup]

JPL:  Orbit Viewer     NEODyS:  object home page [backup] & observations [backup]

Circulars:  MPEC 2004-S05

Notes:  2004 RQ252 was discovered by the Siding Spring Survey on 15 Sept. 2004 and announced the next day. It was posted on 16 Sept. by JPL with impact solutions, and NEODyS posted it on the 17th. Both risk monitors removed it on the 20th, but NEODyS reposted it on Sept. 25th, and JPL on the 28th. And on Oct. 3rd, when the first observations since Sept. 26th became available, both risk monitors again removed all impact solutions. However NEODyS reposted it again on Oct. 4th, 2004.

In the year 2006, 2004 RQ252 was calculated to be back in view for most NEO observers, but has not been reported observed. The Spaceguard Central Node's observing campaign's first page dated April 21st (removed by June 7th) said that it was a "unique recovery opportunity (!) at magnitude 21.0 V. Its sky uncertainty ranges from 34' (max brightness at the end of April) to 20' when it will fade to magnitude 22.0 around the end of May. Large facilities with wide-field of view should make this recovery not difficult."

Packed designation:  K04RP2Q

Current assessments:  NEODyS [backup] & JPL NEOPO

Diameter:  250 meters (JPL estimate)

JPL:  Orbit Viewer     NEODyS:  object home page [backup] & observations [backup]

Packed designation:  99942 (originally K04M04N)

Circulars:  MPECs 2004-Y25, 2004-Y60, 2004-Y63, 2004-Y64, 2004-Y66, 2004-Y68, 2004-Y69, 2004-Y70 & 2004-Y71

  [jump to assessment tables]

Notes:  2004 MN4 was discovered on 19 June 2004 by the team of Roy Tucker, David Tholen, and Fabrizio Bernardi, with Roy Tucker at the 90" Bok Telescope at Kitt Peak in Arizona. It was designated 2004 MN4 at the time, but a discovery MPEC was not issued. This object was rediscovered on 18 Dec. by Gordon Garradd at the Siding Spring Survey (SSS) and it received its first MPEC, 2004-Y25, on the 20th.

After the next observations became available, from SSS on the 22nd, both JPL and NEODyS posted 2004 MN4 with the first-ever Torino Scale 2 rating ("merits concern" for "A somewhat close, but not unusual encounter. Collision is very unlikely."). The next day NEODyS and JPL raised their ratings to yet another unprecedented level — TS-4 ("merits concern" for "A close encounter, with 1% or greater chance of a collision capable of causing regional devastation"). From the 24th forward, both risk monitors also had sets of several impact solutions rated at TS-1 (a routine alert for "merits special monitoring").

On 27 Dec. 2004 it was reported in MPEC 2004-Y70 that 2004 MN4 had been found in images from the Spacewatch 0.9m telescope from March 15th, extending this object's observing arc by a very significant 96.060 days.

Very early on 28 Dec. UT, NEODyS eliminated solutions earlier than 2044 and lowered its overall assessment to TS-1. And JPL soon revised its assessment also to TS-1. On several occasions since going to TS-1, JPL or NEODyS have put out assessments that went to TS-0 (not shown in the compiled risk tables) but were later corrected to TS-1.

2004 MN4 was observed by radar from Arecibo in Puerto Rico on 27, 29, and 30 Jan. and 7 Aug. 2005.

2004 MN4 was numbered 99942 2004 MN4 on 24 June 2005 and 99942 2004 MN4 on 19 July 2005 was named 99942 Apophis after the Greek name for the ancient Egyptian's Apep, god or demon of darkness, chaos, and destruction.

JPL on 5 Aug. 2006 (still the 4th in Pasadena) lowered its 99942 Apophis risk assessment Torino Scale rating to TS-0 ("likelihood of collision is zero, or so low as to be effectively zero"). NEODyS lowered its rating to TS-0 on Sept. 1st.

About astrometry, the Spaceguard Central Node's observing campaign's first page dated April 21st says, "Optical observations not very useful before the apparition in 2013." It was observed again by radar from Arecibo on 6 May 2006, which was reflected in risk assessment updates on May 18th. Optical observations were occasionally reported during January to October of 2006, after which there were none, although 99942 Apophis was calculated to be in view for ground-based telescopes until May of 2007. It next comes into (limited) view in late Nov. 2007.

Resources (newest first)

• JPL summary, "Predicting Apophis' Earth Encounters in 2029 and 2036," with new information and analysis based on radar data, Oct. 2007
• JPL statement, "Radar Observations Refine the Future Motion of Asteroid 2004 MN4," 3 Feb. 2005
• NEODyS statement, "Near-Earth Asteroid 2004 MN4: current status," 2 Feb. 2005
• JPL statement, "Possibility of an Earth Impact in 2029 Ruled Out for Asteroid 2004 MN4," 27 Dec. 2004
• JPL statement, "Near-Earth Asteroid 2004 MN4 Reaches Highest Score To Date On Hazard Scale," issued 23 Dec., updated on the 24th
• Roy Tucker's 1 July 2004 article, "A sweet position," about the observing run in which 2004 MN4 was first discovered, although not mentioned in the article

News coverage (newest first)

• "Asteroid 2004 MN4: A Really Near Miss!" Sky & Tel. 4 Feb. 2005 article
• "Closest Flyby of Large Asteroid to be Naked-Eye Visible," Space.com 4 Feb. 2005 article
• "Asteroid Earth impact in 2029 ruled out," AP story at CNN 29 Dec. 2004
• "Earth Safe from Asteroid 2004 MN4," Sky & Tel. 28 Dec. 2004
• "2004 MN4: swing and a miss," Astronomy.com 27 Dec., updated 28 Dec. 2004
• "Whew! Asteroid Won't Hit Earth in 2029, Scientists Now Say," Space.com 27 Dec. 2004
• "Asteroid Watch: Odds of 2029 Collision Stuck at 1-in-40," Space.com 27 Dec. 2004
• "Worrisome Asteroid Underscores Planetary Defense Mission," Space.com 27 Dec. 2004
• "Asteroid Has Outside Chance of Hitting Earth in 2029," Space.com 24 Dec. 2004
• "Asteroid gets elevated risk rating, but impact unlikely," AP story at Arizona Central 23 Dec. 2004

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