Astrophyzix Observatory - Live PHA NEO Asteroid Tracking, Data Analysis, News

Live Apophis Tracker V5.2 :: Astrophyzix

Integrating Extended N-Body Trajectory

Loading Live Data

DOPRI5(4) :: tol 1e-9 :: 8 planets (Simon 1994) + Moon + 16 MBAs + GR + Yarkovsky

Astrophyzix Flagship Series OBS-09

PHA LIVE N-BODY FLOAT64

Live Apophis Asteroid Tracker Console V5.2

Real-time numerical propagation of PHA asteroid 99942 Apophis using Dormand-Prince 5(4) adaptive Runge-Kutta. Eight major planets seeded from Simon et al. (1994) A&A 282, 663 analytical elements (superseding Standish 1992; planet position error reduced from \~50,000 km to \~500 km). Separated Earth and Moon via Brown-Meeus lunar series, sixteen most-massive main-belt asteroids, Schwarzschild GR correction, and Yarkovsky thermal drag. JPL Horizons orbital solution baseline. Float64 throughout. DOI registered documentation on Astrophyzix.academia.edu and zenodo.org.

INTEGRATORDOPRI5(4)

PERTURBERS26 BODIES

PLANET EPHSIMON 1994

PRECISIONFLOAT64

Documentation/DOI10.5281/zenodo.22828907

EPH ERROR\~500 km

UTC clock initialising...

Integrator Status

SOLVERDOPRI5(4) :: 7-stage FSAL :: PI step

STEPS- steps

TOLERANCEtol 1e-9

SELF-TEST-

PLANET EPHSimon et al. 1994 A&A 282, 663

Closest Approach Countdown

2029 Apr 13 :: 21:46 UTC

38,015 km from geocentre (31,637 km altitude) :: peak mag 3.1 (naked-eye)

Days

Hrs

Min

Sec

Live Position (numerical integration)

HELIO DIST

EARTH DIST

AU / Mkm

SPEED

km / s

VIS MAG

apparent V

RA J2000

h m s

DEC J2000

deg ' "

LIGHT TIME-

RANGE-RATE-

KEPLER RESIDUAL-

OSC. CLASS-

Orbit Canvas

HELIOCENTRIC ECLIPTIC J2000 N-BODY

Time Offset +/-0 d

View

JPL 2029 CA 38,015 km geocentric +/-3.3 km 3-sigma

Ephemeris :: +/-15 days from current offset

Date (UTC)	r (AU)	Delta (AU)	v (km/s)	Mag	RA	Dec	Elong

Estimated Light Curve (H=19.09, G=0.24)

Speed Context

ISS orbital speed

7.7 km/s

Apophis vs Earth (flyby)

7.4 km/s

Apophis at aphelion

25.5 km/s

Earth around Sun

29.8 km/s

Apophis at perihelion

37.7 km/s

Apophis NOW

Live Force Budget (current cached state)

Magnitude of each acceleration term acting on Apophis at the current time offset. Bars are log-scaled (each tick = x10). Sun is the central two-body force; everything else is what makes Kepler propagation drift. MBAs Sum is the vector sum of the Big-16 main-belt asteroid contributions.

Notable Near-Earth Asteroids

Object	Diameter	e	a (AU)	Class	Visited by
99942 Apophis	\~340-450 m	0.192	0.923	PHA, Aten	OSIRIS-APEX, Ramses
101955 Bennu	490 m	0.204	1.126	PHA, Apollo	OSIRIS-REx (sample 2023)
65803 Didymos	780 m + 150 m	0.384	1.644	PHA, binary	DART (2022), Hera (2026)
162173 Ryugu	900 m	0.190	1.190	Apollo, C-type	Hayabusa2 (sample 2020)
433 Eros	16.8 km	0.223	1.458	Amor, S-type	NEAR Shoemaker (2001)

Orbital Elements (JPL Horizons :: Soln 2024-Jun-25)

ECCENTRICITY (e)0.19152moderately elliptical

SEMI-MAJOR AXIS (a)0.92251 AUsmaller than Earth orbit

PERIHELION (q)0.74583 AUjust outside Venus orbit

APHELION (Q)1.09919 AUjust outside Earth orbit

INCLINATION (i)3.337 deglow - near ecliptic

ASC NODE (Omega)204.039 deg

ARG PERIHELION126.652 deg

ORBITAL PERIOD (P)0.886 yr (323.6 d)Aten-class NEO

EPOCHJD 2459215.52021-Jan-01.0 TDB

Physical and Derived

DIAMETER\~340-450 mpeanut-shaped, \~170 m short axis

ABSOLUTE MAG (H)19.09Sq-class (stony)

ALBEDO0.350moderately reflective

ROTATION30.56 hrnon-principal-axis tumbler

EARTH MOID0.000382 AU\~57,200 km - extremely close

YARKOVSKY A2-2.901e-14 AU/d^2Perez-Hernandez and Benet 2022

MEAN MOTION (n)1.1124 deg/day

SPEED PERIHELION37.7 km/svis-viva, heliocentric

SPEED APHELION25.5 km/s

DISCOVERY2004-Jun-19Tucker, Tholen, Bernardi (Kitt Peak)

2029 Flyby :: Once-in-a-Generation Event

CLOSEST APPROACH2029 Apr 13, 21:46 UTCFriday the 13th

DIST FROM SURFACE31,637 kmWGS84 equatorial radius

DIST FROM CENTRE38,015.1 km0.000254115 AU :: +/-3.3 km 3-sigma

GEO BELT ALTITUDE35,786 kmApophis passes INSIDE the GEO ring

PEAK MAGNITUDE+3.1naked-eye visible

EARTH-RELATIVE SPEED7.4 km/sat closest approach

ANGULAR SPEEDup to 42 deg/hr\~8 lunar diameters per minute

VISIBLE FROMEurope, Africa, W Asiamoves Centaurus to Pisces (205 deg arc)

LUNAR PASS (16h LATER)\~95,000 km from Moon

IMPACT PROBABILITY0ruled out for >100 yr (Sentry, 2021)

Mission and Discovery Timeline

2004 Jun 19

Discovery - Tucker, Tholen, Bernardi at Kitt Peak; provisional designation 2004 MN4.

2004 Dec 27

Peak impact scare - 2.7% chance of 2029 impact; reaches Torino Scale level 4 (highest ever).

2005 Jul

Numbered and named - asteroid (99942) Apophis, after the Egyptian god of chaos.

2013 Jan 09

Earth flyby at 0.097 AU - Goldstone and Arecibo radar observations rule out 2036 impact.

2021 Mar 06

0.113 AU flyby - radar observations rule out impact for over 100 years; removed from Sentry table.

2024 Jun

Latest orbit solution - JPL refines trajectory with Yarkovsky effect; 2029 distance uncertainty +/-3.3 km.

2028 Apr

ESA Ramses launch - Rapid Apophis Mission for Space Safety; arrives Feb 2029.

2029 Apr 13

CLOSE APPROACH - 21:46 UTC; 38,015 km from geocentre (inside GEO); mag 3.1; visible naked-eye from Europe and Africa.

2029 Jun

OSIRIS-APEX arrival - NASA spacecraft (formerly OSIRIS-REx) studies post-encounter Apophis.

2036 Mar 30

Next approach - 0.31 AU (\~46 million km); orbit now Apollo-class after the 2029 perturbation.

2051 Apr 19

0.04 AU approach - first sub-10-million-km pass after 2029.

JPL Horizons reference :: JPL#220 / SBDB

Published solution, not a product of this integrator. 3-sigma uncertainty +/-3.3 km on the geocentric miss. Surface figure uses WGS84 equatorial radius 6378.137 km.

CLOSEST APPROACH2029 Apr 13, 21:46 UTCFriday the 13th

GEOCENTRIC DIST38,015.1 km0.000254115 AU

ALTITUDE (WGS84 eq.)31,637 kmGEO ring 35,786 km altitude — Apophis passes inside

3-SIGMA+/-3.3 km

EARTH-RELATIVE SPEED7.4 km/s

PEAK V MAG+3.1naked-eye from Europe / Africa / W. Asia

IMPACT PROBABILITY0ruled out for >100 yr (Sentry, 2021)

This model :: independent CA on the DOPRI5 cache

Closest Earth approach found by ternary search on interpolated n-body states. Simon 1994 planet ephemeris is \~500-3000 km vs DE441, so kilometre-level agreement with JPL is not expected. The residual is a diagnostic of the 26-body model, not a new orbit solution.

COMPUTED CA (UTC)integrating...

dt vs JPL-

GEOCENTRIC (MODEL)-

ALTITUDE (MODEL)-

RESIDUAL vs JPL GEO-

RELATIVE SPEED-

v-inf (hyperbolic excess)-

DISTANCE TO MOON-

INSIDE GEO RING-

Aten to Apollo :: osculating elements +/-20 d about CA

CLASS BEFORE-

CLASS AFTER-

a BEFORE-

a AFTER-

e BEFORE-

e AFTER-

Runtime Capability Probe

Memory and Storage

Provenance Manifest

All numerical results carry a provenance hash recording the integrator, perturber list, tolerances, and parameter set used to produce them. Persisted to IndexedDB for cross-session reproducibility.

Initial conditions: JPL Horizons orbital solution, soln 2024-Jun-25, epoch JD 2459215.5
Frame: heliocentric ecliptic J2000 for state, BCRS/TDB for time
Planet ephemeris: Simon et al. (1994) A&A 282, 663 - replaces Standish (1992)
Perturbers: 8 planets + Moon (separated) + Big-16 MBAs = 25 bodies
Planet positions: Simon 1994 mean elements; Moon: Brown-Meeus truncated series
Asteroids: fixed Keplerian propagation with precomputed rotation matrices
Integrator: Dormand-Prince 5(4) embedded RK, 7-stage FSAL, PI step controller p=5
Tolerance: abs/rel 1e-9 in scaled error norm
Yarkovsky: A2 = -2.901e-14 AU/d^2 (Perez-Hernandez and Benet 2022)
GR: Schwarzschild correction at the Sun only
Sun J2: 2.2e-7 with R_sun = 0.004652478 AU
SRP: 5.36e-13 AU/d^2 at 1 AU