ANEOPP Home Page

The Arcetri Near Earth Object Precovery Program (ANEOPP)

The Arcetri Near-Earth Object Precovery Program (ANEOPP) is dedicated to the systematic search of NEO images on existing photographic plate archives.

ANEOPP was born in July 1999 of a collaboration between Andrea Boattini, Astronomical Observatory of Rome, and Giuseppe Forti, Arcetri Astrophysical Observatory in Florence.

Later other people became involved with this project: Roy Gal, Maura Tombelli, Luciano Tesi and Germano D'Abramo.

The main goal of ANEOPP is to locate newly discovered NEOs on old observations as soon as possible. This reduces the amount of time needed from follow-up observing stations in securing preliminary orbits for future recoveries. The contribution of this program has been conceived as a segment of the worldwide NEO follow-up efforts under the coordination of the Spaceguard Central Node . It also works in close collaboration with the Department of Mathematics at the University of Pisa and with the observing activities at San Marcello Pistoiese and Montelupo observatories.

Introduction
Archives available
Activity
Team
Results and statistics
Selected images
Acknowledgements

• Summary Report from Edinburgh

Introduction

Photographic archives from wide-field telescopes represent a huge resource for improving our orbital knowledge of minor planets and, in particular, Near-Earth Objects. It is estimated that there are two million plates/films worldwide from professional collections. The work of locating minor planets on archival images is called precovery (recovery from pre-existing images).

Even though most of these archives are not really suitable for astrometric purposes because of their poor limiting magnitude, scale and state of conservation, there are very useful collections that have not been explored yet. Probably the most valuable such resources are those collected with the biggest Schmidt telescopes because of their deep limiting magnitude. Telescopes in this size class have been used over the last few decades to map the entire sky in different colours. Print copies of these surveys have been distributed all over the world and represent our current resource of identifications.

Precovery searching of minor planets (comets and asteroids) is not a new activity and it led to the achievement of scientifically valuable results. For example, the identification of the Amor-type object (4015) = 1979 VA with Periodic Comet Wilson-Harrington on a plate from 1949, showed clear evidence that the distinction between asteroids and comets is not very straightforward. Two well-known comets, P/Swift-Tuttle and Hale-Bopp had their orbital solutions significantly improved thanks to precovery data.

After the initial efforts from the AANEAS program in Australia, made since 1990, newly discovered NEOs are now routinely searched for on photographic archives by a few dedicated programs. Most such archival collections still remain unaccessible, but after the recent precoveries of two potential hazardous objects for the Earth, 1997 XF11 and 1999 AN10, more efforts will be made to improve this situation.

Archives available

Two main sources are usually available for this activity:

a) The Arcetri Plate Library
b) The Digitized Sky Survey

The Arcetri Plate Library

The Arcetri Plate Library became regularly available in February 2000. The first result was the identification of the Apollos 2000 CN101 and 2000 BF19. It consists of the following plate copy collections:

• Palomar Observatory Sky Survey I (POSS-I)
• Palomar Observatory Sky Survey II ( POSS-II)
• SERC-EJ + SERC-J copies from the UK Schmidt Telescope archive ( UKST)
• A few SR and I copies from the UK Schmidt Telescope archive

Checks at the plate library are usually conducted twice a month, when time allows. Precoveries of targets with higher ephemeris uncertainties are made on the plate copies with an eyepiece, although most identifications are made on the Digital Sky Survey. The print copies of the POSS-I are virtually useless due to their poor quality, and so far, have not been utilized.

The Digitized Sky Survey (DSS)

Most of the work with ANEOPP is performed using the Digitized Sky Survey (DSS). Currently, two sources are used:

• The The Space Telescope Science Institute (STScI) Digitized Sky Survey .
• The US Naval Observatory (USNO) Digitized Sky Survey.

These databases have many digitized plates in common, but not all. They include a set of plates from the 1.2-m UK Schmidt telescope (UKST) at Siding Spring Observatory, Australia, and the 1.2-m Oschin Schmidt telescope at Mount Palomar Observatory. The USNO collection also includes a set of digitized red plates taken with the 1.1-m European Southern Observatory (ESO) Schmidt telescope at La Silla, Chile.

DSS images are always used for astrometric purposes whether or not the object has been found directly on them. When the digitized images do not look satisfactory, compared with the plate copies in the library, a new digitization of a portion of the plate copy is repeated at the observatory laboratory.

From the summer of 1999, Roy Gal of the California Institute of Technology (Caltech), has provided images from the Digitized Palomar Observatory Sky Survey (DPOSS), that could not be retrieved from the web. This is part of a collaboration with Caltech that we hope to expand in the future to include the team led by Eleanor Helin of the Jet Propulsion Laboratory (JPL).

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Working with the UKST archive at Edinburgh: a Preliminary Report

The work of ANEOPP with non survey plates from the UK Schmidt archive at Edinburgh is over for now. A systematic search for images of known NEOs with poor orbits was carried out from September 19 to October 3, 2000. About 300 plates were investigated, resulting in the identification of about 30 NEOs. For more information you can read this Summary Report.

Activity

The great bulk of the precovery work has been focused towards NEOs observed only in the course of one opposition. It is organized in a few steps:

• As soon as a preliminary orbit of a new object is available, we produce fully perturbed n-body ephemerides using the Orbfit software and compare it to the catalog files of the UK, Palomar and ESO Schmidt archives, in order to identify possible candidates. Self-made software, mostly done by G. Forti, is used for this task. The output (a list of candidate plates) is available in different forms, depending on the expected ephemeris uncertainty of the target and the amount of time we can invest.

• The second step is to distinguish the plates that are available as copies in the plate library from those in digitized form.

• As soon as we have located an identification opportunity, we produce the relative observing prediction, which shows the line of variation (l-o-v) of the object.

• Any candidate close to the l-o-v, with motion rate and magnitude close to the predictions, is measured using the USNO A2.0 catalogue.

• If the orbital linkage with the new data is successful, the cross-checking process is repeated in order to locate additional images of the object, with the advantage of a much smaller ephemeris uncertainty. After this step the data are finally submitted to the Minor Planet Center. Two different nights are now necessary for the issue of a precovery M.P.E.C..

Other groups working on a similar program:

DANEOPS, the DLR-Archenhold Near Earth Objects Precovery Survey

ANEOPP Team

Principal investigators

Mike Read - Royal Observatory, Edinburgh

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Results and Statistics

Atens, Apollos, Amors

All of the detections listed below refer to NEOs that were observed only in the course of one opposition and later became multi-opposition targets following these identifications.

From POSS-I

1999 GJ4 *, 1999 YT , 1999 UM3 , 2000 CQ101, 2000 ED104, 1998 WT

From POSS-II

1998 MX5 , 1997 WT22 , 1997 GL3 , 1999 HZ1 , 2000 BF19 , 1998 QH2 ,

1999 WC2 , 1999 XA143 , 1999 RD32 , 2000 DH8 , 2000 GP82 , 2000 DV110 ,

2000 PN9 , (2000 QJ1) , 2000 NG11 , 1998 NU , 2000 GV147 , 2000 UV13 ,

2000 UT16 , 2000 VM2 , (2000 YK29), (2000 YJ66), (2001 BW15), 2001 AU43 ,

2001 KY66 , 2001 MG1 , 2001 SL9 , (2001 RM) , 2002 AW , 2001 RP17 ,

2002 LJ3 , 2002 KH4 , 2002 VT85 , 2002 NT7 , 2002 XA40

From UKSTU (survey plates)

1996 BZ3 , 1999 LF6 , 1998 FM5 , 2000 CN101 , 1999 VM40 , 1999 RH33 ,

(2000 ES70) , 2000 BO28 , 2000 GQ146 , 2000 GC2 , 2000 GR146 , 2000 HO14 ,

2000 JQ66 , 2000 HA24 **, 2000 HD24 , 2000 CG59 , 2000 LY27 , 2000 JN10 ,

2000 PM8 , 2000 SY2 , 2000 SE45 , 2000 VN2 , 2001 TN41 , 2002 CE

From UKSTU (non survey plates - Edinburgh)

1999 RM28 ***, 1998 YB8 , 1999 JU3 , 2000 JS66 , 1998 WM , 1999 KX4 ,

1999 RR28 , 2000 QP , 1998 OR2 , 2000 EZ148 , 1998 UT18 , 1998 BX7 ,

1999 GJ2 , 1992 BL2 , 1999 YB , 2000 NF11 , 1999 JV3 , 1999 LQ28 ,

1999 RP36 , 2000 JT66 , 2000 PG5 , 2000 UV16 , 2000 WP148 , 2000 XK44 ,

2001 CV26 , 2000 XK47 , 2001 LE6 , 2001 QL142 , 2001 TC2 , 2001 WR1 ,

2001 YJ4 , 2002 CC19 , 2002 GD11 , 2002 HK12 , 2002 JM97 , 2003 BD44 ,

2002 TN30

From ESO plates

2002 BY

From PACS project at Mount Palomar

2001 MQ3 , 2001 QH96 , 1998 QQ63 , 2000 XL44 , 2002 AU4

From identifications on existing observations or similar data

1998 MR24**** , 1991 NT3

Notes:

Objects in parenthesis are independent detections.

* 1999 GJ4 was found in the course of a joint effort with a team led by Ted Bowell at the Lowell Observatory in Arizona.

** 2000 HA24 was independently located by E. Helin and K. Lawrence on 1993 photos from the PCAS archive.

*** 1999 RM28 was located and measured by R. H. McNaught based on ANEOPP predictions.

**** 1998 MR24 was independently identified by G. Sansaturio.

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This plot shows the size distribution in absolute magnitude (H) of the Atens, Apollos, Amors (NEAs) precovered by ANEOPP. The cut-off towards the bigger objects can be explained by the fact that few of them were single-opposition targets at the time of the identification, but also a minor fraction of them still remains undiscovered. The cut-off on the side of faint magnitudes is justified both by the relative small number of known NEAs of this size and the more infrequent opportunities to record them accidentally on photographic plates.

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NEOs found in the course of their discovery apparition

Some time has been invested in locating NEO trails during their discovery apparition, in order to extend the observing arc. Following is a list of targets found under these circumstances:

1988 PA (*), 1989 VB (**), 1991 TB2 (**), 1992 BC (**), 1992 SZ (***),

1994 NE (***), 1995 WL8 (***), 1997 YM3 (*)

(*) it indicates that the object is now easily recoverable (unlike before).

(**) it indicates that a direct recovery is still very difficult, but not

impossible (unlike before when the object was completely lost). The best

examples of this situation are the cases of 1991 TB2 and 1992 BC.

(***) it means that the precovery observations have not significantly improved

the status of the recovery prospects.

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Other NEOs

Occasionally we have located and measured multi-opposition NEOs, but it is not a priority of this project, unless they show significant sky uncertainty. Here is a list of such findings:

1950 DA, 1991 VE, 1996 AS1, 1997 WS22, 1997 XF11, 1998 EP8, 2000 NF5, (02212), 2000 OG, 1998 TX6, 1991 NT3, 1991 JG1, 2001 RM

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In addition to the work on Near-Earth Objects, a little time is also devoted to other minor planet populations: Unusual objects, main-belt objects and Centaurs. Here follows a very brief overview of the results.

Unusual objects

1998 XB9 , 1996 TE11 , 1999 US3

Centaurs

(10199) = Chariklo

Main belt objects

Another segment of the activity is the identification of precovery images of main-belt objects (MBO) discovered from several Italian observing stations: Cima Ekar (098), San Marcello Pistoiese (104), Montelupo (108), Campo Imperatore (599) and Pianoro (610). The MBO program is coordinated by Maura Tombelli and Luciano Tesi.

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Selected Images

We have chosen images of two NEAs: 2000 LY27 and 2000 BF19. They have been some of the most difficult objects to locate, with ephemeris uncertainty of many degrees. The object with the highest ephemeris uncertainty found so far, is 1998 NU, as you can see here.

The PHA 2000 LY27 was located on June 14, 2000 on a Siding Spring photographic plate copy available at Arcetri Observatory. This plate, taken on 1976 June 28, was digitized by the US Naval Observatory. 2000 LY27, at magnitude 18.4 V, is the short trailed object at the centre of the image. It was discovered by LINEAR on June 7, 2000.

As often happens, many NEO trails recorded on these deep archives do not show high motion rates and could not be distinguished from main-belt objects at the time the plate was taken. The occurence of these short NEO trailed images is due to the reduced loss in limiting magnitude because of the trailing effect.

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2000 BF19

The location of 2000 BF19 on a POSS-2 plate marks the beginning of regular access to the Arcetri Plate Library. Discovered by the Spacewatch program on January 28, 2000, 2000 BF19 was put to the attention of the Astronomical Community during the early stages of the follow-up process, because it was found to have a remote chance of a collision with the Earth. Further observations averted this possibility and allowed the identification of the following precovery image, digitized by the STScI. It was taken on October 4, 1991 in the course of the POSS II, with BF19 being of magnitude 18.

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Acknowledgements

The DSS are copyrighted material. See their proper acknowledgements.

We thank and acknowledge all the observers who took the original plates included in this project. While we have the appropriate information for most of the plates taken in the course of the POSS II, unfortunately we have just about nothing for the other surveys.

We also want to thank all the people that helped us during the early stages of this program. Particular thanks go to Dr. Gian Paolo Tozzi of the Arcetri Observatory for giving us access to the plate library.

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For questions about this page, please contact Giuseppe Forti or Andrea Boattini

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Updated on May 23, 2003, by Andrea Boattini and Giuseppe Forti