Digital Astronomical Archeology: the Data Base of Physical and Dynamical Properties of Near Earth Asteroids (NEAs)

The Data Base of Physical and Dynamical Properties of Near Earth Asteroids (NEAs), was developed by Gerhard Hahn at the Institute of Planetary Research of the German Aerospace Center (DLR) in Berlin-Adlershof, Germany.It went offline fromt the DLR website around 2015, however it was mirrored and archived by the WaybackMachine (https:/archive.org).

The present dataset was recovered through systematic extraction from archived snapshots of the original E.A.R.N. website, preserved by the Internet Archive's Wayback Machine. By identifying all reachable NEA pages within the archived structure, the content was programmatically downloaded, parsed, and converted into structured tabular form. This process enabled the restoration of individual asteroid records, including their observational and physical parameters, as they were originally presented, effectively reconstructing the full E.A.R.N. NEA database in machine-readable format.

The reconstructed dataset represents a comprehensive archive of Near-Earth Asteroid (NEA) physical, photometric, and taxonomic properties as they were compiled by the European Asteroid Research Node (E.A.R.N.) during its operational period. This includes:

Astrometric and discovery metadata, such as discovery dates, observing sites, and Minor Planet Center references;

Photometric parameters, including absolute magnitude (H), slope parameter (G), and color indices (U-B, B-V, V-R, R-I);

Physical properties, such as estimated diameter (including uncertainty ranges), albedo (measured or inferred), rotation periods, and lightcurve amplitudes;

Taxonomic classifications derived from spectral or photometric surveys;

Spin and rotation state information, when available, including spin vector orientations and sense of rotation;

Supporting observational datasets, such as radar, infrared, and spectral observations;

Linkages to external databases (e.g., NEODyS, CBAT, MPEC) for orbit refinement and historical discovery context;

Archival timestamps documenting when each record was preserved via web capture.

The dataset reflects the state of NEA knowledge and classification as published by E.A.R.N. before its disappearance. Its historical value lies in preserving legacy designations, early estimates of physical parameters, and provenance of scientific interpretation that may differ from or precede current catalogs such as JPL SBDB or MPCORB.

This reconstruction is a contribution to astronomical data preservation, enabling continued access to an otherwise lost research asset.

The original webpage is available via archive.org at this link https://web.archive.org/web/20150905141056fw_/http://earn.dlr.de/nea/

A total of 11,552 Near-Earth Asteroid (NEA) records were successfully recovered from the archived E.A.R.N. database via the Internet Archive. This includes:

5,944 Apollo-class asteroids (out of 6,400 originally listed)

4,653 Amor-class asteroids (out of 5,592)

955 Aten-class asteroids (out of 956)

The remaining 1,395 records could not be retrieved, as they were not preserved in the Wayback Machine’s archive. The reconstructed dataset thus represents 89.2% coverage of the original E.A.R.N. NEA catalog.

The dataset contains the following fields.

Filename, [string]: Original file name of the archived HTML page.designation, [string]: Official IAU designation of the asteroid.designation_provisional, [string]: Alternate or provisional designation.designation_compact, [string]: MPC-style packed designation used for internal cross-referencing.designation_neodys, [string]: Object identifier used in NEODyS URL queries.archive_date, [string]: Date and time (ISO 8601) when the page was archived on the Wayback Machine.

Discovery_Circumstances, [string]: Raw discovery text including observer and date.Discovery_Circumstances_ref, [string]: Reference code or label for discovery information.Observatory_Name, [string]: Name of observatory or survey responsible for the discovery.Discovery_Date, [string]: Discovery date in ISO format (YYYY-MM-DD).Discovery_Mjd, [REAL]: Modified Julian Date of discovery.Discovery_Year, [REAL]: Discovery year expressed as a decimal.

Orbital_Type, [string]: Orbital class (e.g., AM = Amor, AP = Apollo, AT = Aten).Orbital_Type_ref, [string]: Reference source for orbital type.

Taxonomic_Type, [string]: Taxonomic classification (e.g., S, C, X, etc.).Taxonomic_Type_ref, [string]: Reference source for taxonomic classification.

Albedo, [string]: Original albedo string (may include codes or symbols).Albedo_Value, [REAL]: Parsed geometric albedo as a numeric value.Albedo_ref, [string]: Reference for the albedo measurement or estimate.

Diameter, [string]: Original text describing estimated diameter.Diameter_ref, [string]: Reference for the diameter estimate.Diameter_Min, [REAL]: Minimum estimated diameter (in kilometers).Diameter_Max, [REAL]: Maximum estimated diameter (in kilometers).Diameter_Mean, [REAL]: Mean of min and max diameter, or single value if range not present.

H, [string]: Original absolute magnitude (H) as reported.H_Value, [REAL]: Parsed absolute magnitude (H) as numeric.H_ref, [string]: Reference source for H.

G, [REAL]: Slope parameter G (used in H-G system).G_ref, [string]: Reference for G.

U-B, [REAL]: U–B color index (ultraviolet minus blue).U-B_ref, [string]: Reference for U–B.B-V, [REAL]: B–V color index (blue minus visual).B-V_ref, [string]: Reference for B–V.V-R, [REAL]: V–R color index (visual minus red).V-R_ref, [string]: Reference for V–R.R-I, [REAL]: R–I color index (red minus infrared).R-I_ref, [string]: Reference for R–I.

Rotation_Period, [REAL]: Measured rotation period in hours.Rotation_Period_ref, [string]: Reference for rotation period.

Quality, [string]: Quality rating of the lightcurve or rotational data.Quality_ref, [string]: Reference for quality flag.

Lightcurve_Amplitude, [REAL]: Amplitude of brightness variation in lightcurve (magnitudes).Lightcurve_Amplitude_ref, [string]: Reference for amplitude.

Spin_Vector, [string]: Description of spin axis orientation, if available.Spin_Vector_ref, [string]: Reference for spin vector data.

Sense_of_Rotation, [string]: Reported sense of rotation (e.g., prograde, retrograde).Sense_of_Rotation_ref, [string]: Reference for rotation sense.

Radar_Observations, [string]: Presence or description of radar data.Radar_Observations_ref, [string]: Reference for radar observations.

Spectral_Observations, [string]: Summary of spectral observations.Spectral_Observations_ref, [string]: Reference for spectral data.

IR_Observations, [string]: Presence of infrared observations.IR_Observations_ref, [string]: Reference for IR data.

NEODyS_Link, [URL]: Link to the NEODyS dynamic orbit page.CBAT_Link, [URL]: Link to CBAT circular or publication (if available).MPEC_Link, [URL]: Link to the MPEC notice reporting discovery or updates.

References, [string]: Structured list of references associated with the entry.