Exclusivo para Infobservador
Un NEO interesante, porque es bastante grande para poder verlo con telescopios pequeños.
 |
| La órbita del NEO 1998 OR2. |
Y durante este paso esta en posicion muy buena para el hemisferio sur.
¿Que es un NEO?
Son los Near Earth Objetcs, u objetos cercanos a la Tierra. Son pequeños asteroides que tienen órbitas similares a la de nuestro planeta, y por lo tanto, pueden aproximarse mucho.
1998 OR2
Este NEO fue descubierto el 24 de julio de 1998, por NEAT.
Pasará este año a "solo" 6,3 millones de km, (distancia totalmente segura!), el 29 de abril de 2020, a las 9:56 TU (6:56 hora legal Argentina). El asteroide tiene entre 1,8 y 4 km. Su velocidad orbital en ese momento será de 37 km/seg, pero con referencia a la Tierra, de 9 km/seg.). Alcanzará la magnitud 10,9.
 |
| Momento en que pasa mas cercano, el 29/4/2020. A la derecha, nuestro planeta y la órbita de la Luna. |
La Predicción
Varias cosas. Cuando hay objetos como este, muy cercanos, se presenta el recorrido visto desde el centro de la Tierra, lo que significa que puede estar en realidad (en este caso) hasta 3 minutos de arco de la predicción. (moviéndose paralelamente a la línea de recorrido).
Tal vez lo ideal sea que cargues el NEO en el Stellarium, que te dará el recorrido más cercano a la realidad, desde tu lugar de observación.
En el enlace, puedes ver como cargar este asteroide en el Stellarium.
Hay dos momentos interesantes:
1) En la máxima cercanía, el 29/4, porque se mueve muy rápidamente. Aproximadamente unos 8" por minuto. Es lo suficientemente rápido para que se note, si te quedas un rato mirando.
2) Entre el 5 y 6 de mayo, pasará pegado a la galaxia NGC 4945.... todavía con mag. 11. Ideal para una foto.
Al final tienes la efeméride precisa.
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Ephemeris / WWW_USER Mon Apr 20 05:21:12 2020 Pasadena, USA / Horizons
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Target body name: 52768 (1998 OR2) {source: JPL#267}
Center body name: Earth (399) {source: DE431}
Center-site name: GEOCENTRIC
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Start time : A.D. 2020-Apr-20 00:00:00.0000 UT
Stop time : A.D. 2020-May-20 00:00:00.0000 UT
Step-size : 1440 minutes
*******************************************************************************
Target pole/equ : No model available
Target radii : (unavailable)
Center geodetic : 0.00000000,0.00000000,0.0000000 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 0.00000000,0.00000000,0.0000000 {E-lon(deg),Dxy(km),Dz(km)}
Center pole/equ : High-precision EOP model {East-longitude positive}
Center radii : 6378.1 x 6378.1 x 6356.8 km {Equator, meridian, pole}
Target primary : Sun
Vis. interferer : MOON (R_eq= 1737.400) km {source: DE431}
Rel. light bend : Sun, EARTH {source: DE431}
Rel. lght bnd GM: 1.3271E+11, 3.9860E+05 km^3/s^2
Small-body perts: Yes {source: SB431-N16}
Atmos refraction: NO (AIRLESS)
RA format : HMS
Time format : CAL
EOP file : eop.200417.p200709
EOP coverage : DATA-BASED 1962-JAN-20 TO 2020-APR-17. PREDICTS-> 2020-JUL-08
Units conversion: 1 au= 149597870.700 km, c= 299792.458 km/s, 1 day= 86400.0 s
Table cut-offs 1: Elevation (-90.0deg=NO ),Airmass (>38.000=NO), Daylight (NO )
Table cut-offs 2: Solar elongation ( 0.0,180.0=NO ),Local Hour Angle( 0.0=NO )
Table cut-offs 3: RA/DEC angular rate ( 0.0=NO )
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Initial IAU76/J2000 heliocentric ecliptic osculating elements (au, days, deg.):
EPOCH= 2457974.5 ! 2017-Aug-09.00 (TDB) Residual RMS= .20588
EC= .5727639048894702 QR= 1.016720044390039 TP= 2457613.8448492307
OM= 27.06410119583914 W= 174.4445667255005 IN= 5.87964679192903
Equivalent ICRF heliocentric equatorial cartesian coordinates (au, au/d):
X= 3.095301678671118E+00 Y=-3.893597904220648E-01 Z=-3.776013431256448E-01
VX= 5.098871090737723E-03 VY= 5.517439085124372E-03 VZ= 2.746893703798376E-03
Asteroid physical parameters (km, seconds, rotational period in hours):
GM= n.a. RAD= n.a. ROTPER= 4.112
H= 15.8 G= .150 B-V= n.a.
ALBEDO= n.a. STYP= n.a.
***************************************************************************************
Date__(UT)__HR:MN R.A._____(ICRF)_____DEC APmag delta deldot Cnst
***************************************************************************************
$$SOE
2020-Apr-20 00:00 08 57 51.83 +17 52 16.1 12.45 0.06283672546357 -6.2853317 Cnc
2020-Apr-21 00:00 09 05 02.29 +15 12 04.0 12.28 0.05929027739466 -5.9841805 Cnc
2020-Apr-22 00:00 09 12 56.45 +12 10 51.6 12.11 0.05593639020171 -5.6166511 Cnc
2020-Apr-23 00:00 09 21 39.81 +08 46 10.9 11.93 0.05281690404395 -5.1704822 Cnc
2020-Apr-24 00:00 09 31 18.44 +04 55 55.6 11.74 0.04998088998409 -4.6331186 Hya
2020-Apr-25 00:00 09 41 58.94 +00 38 51.8 11.55 0.04748433838178 -3.9935524 Sex
2020-Apr-26 00:00 09 53 48.20 -04 04 40.5 11.37 0.04538846344497 -3.2452848 Sex
2020-Apr-27 00:00 10 06 53.13 -09 11 59.7 11.20 0.04375600782440 -2.3901951 Sex
2020-Apr-28 00:00 10 21 20.06 -14 37 25.0 11.05 0.04264527820000 -1.4422702 Hya
2020-Apr-29 00:00 10 37 13.97 -20 12 09.4 10.93 0.04210252169831 -0.4292507 Hya
2020-Apr-30 00:00 10 54 37.34 -25 45 04.2 10.84 0.04215445214454 0.6097734 Hya
2020-May-01 00:00 11 13 28.87 -31 04 13.9 10.80 0.04280347004384 1.6311073 Hya
2020-May-02 00:00 11 33 42.07 -35 58 53.2 10.79 0.04402751319513 2.5951501 Cen
2020-May-03 00:00 11 55 04.23 -40 21 03.0 10.83 0.04578458259939 3.4732887 Cen
2020-May-04 00:00 12 17 16.26 -44 06 15.8 10.89 0.04802007238347 4.2505254 Cen
2020-May-05 00:00 12 39 53.71 -47 13 29.1 10.98 0.05067437400438 4.9240334 Cen
2020-May-06 00:00 13 02 29.05 -49 44 22.5 11.09 0.05368891709216 5.4995568 Cen
2020-May-07 00:00 13 24 34.84 -51 42 23.0 11.20 0.05700999248477 5.9875927 Cen
2020-May-08 00:00 13 45 46.86 -53 11 53.3 11.33 0.06059058698195 6.4004223 Cen
2020-May-09 00:00 14 05 46.35 -54 17 30.5 11.46 0.06439081958570 6.7502281 Cen
2020-May-10 00:00 14 24 20.96 -55 03 39.1 11.58 0.06837756284079 7.0481061 Lup
2020-May-11 00:00 14 41 24.55 -55 34 14.7 11.71 0.07252368034188 7.3036759 Cir
2020-May-12 00:00 14 56 56.13 -55 52 37.9 11.83 0.07680714849155 7.5250334 Cir
2020-May-13 00:00 15 10 58.43 -56 01 33.4 11.95 0.08121020726397 7.7188758 Cir
2020-May-14 00:00 15 23 36.65 -56 03 13.5 12.07 0.08571860560971 7.8906917 Cir
2020-May-15 00:00 15 34 57.29 -55 59 22.5 12.18 0.09032096180150 8.0449617 Nor
2020-May-16 00:00 15 45 07.42 -55 51 21.2 12.28 0.09500823577030 8.1853435 Nor
2020-May-17 00:00 15 54 14.09 -55 40 12.2 12.39 0.09977330031675 8.3148280 Nor
2020-May-18 00:00 16 02 24.01 -55 26 43.3 12.48 0.10461059501938 8.4358697 Nor
2020-May-19 00:00 16 09 43.42 -55 11 31.0 12.58 0.10951584707854 8.5504890 Nor
2020-May-20 00:00 16 16 17.95 -54 55 03.0 12.67 0.11448584522347 8.6603537 Nor
$$EOE
***************************************************************************************
Column meaning:
TIME
Times PRIOR to 1962 are UT1, a mean-solar time closely related to the
prior but now-deprecated GMT. Times AFTER 1962 are in UTC, the current
civil or "wall-clock" time-scale. UTC is kept within 0.9 seconds of UT1
using integer leap-seconds for 1972 and later years.
Conversion from the internal Barycentric Dynamical Time (TDB) of solar
system dynamics to the non-uniform civil UT time-scale requested for output
has not been determined for UTC times after the next July or January 1st.
Therefore, the last known leap-second is used as a constant over future
intervals.
Time tags refer to the UT time-scale conversion from TDB on Earth
regardless of observer location within the solar system, although clock
rates may differ due to the local gravity field and no analog to "UT"
may be defined for that location.
Any 'b' symbol in the 1st-column denotes a B.C. date. First-column blank
(" ") denotes an A.D. date. Calendar dates prior to 1582-Oct-15 are in the
Julian calendar system. Later calendar dates are in the Gregorian system.
NOTE: "n.a." in output means quantity "not available" at the print-time.
R.A._____(ICRF)_____DEC =
Astrometric right ascension and declination of the target center with
respect to the observing site (coordinate origin) in the reference frame of
the planetary ephemeris (ICRF). Compensated for down-leg light-time delay
aberration.
Units: RA in hours-minutes-seconds of time (HH MM SS.ff)
DEC in degrees-minutes-seconds of arc (sDD MN SC.f)
APmag =
Asteroid's approximate apparent visual magnitude from the standard
IAU H-G magnitude relationship:
APmag = H + 5*log10(delta) + 5*log10(r) - 2.5*log10((1-G)*phi1 + G*phi2).
For solar phase angles > 90 deg, the error could exceed 1 magnitude. For phase
angles > 120 degrees, output values are rounded to the nearest integer to
indicate error could be large and unknown.
Units: MAGNITUDE
delta deldot =
Range ("delta") and range-rate ("delta-dot") of target center with respect
to the observer at the instant light seen by the observer at print-time would
have left the target center (print-time minus down-leg light-time); the
distance traveled by a light ray emanating from the center of the target and
recorded by the observer at print-time. "deldot" is a projection of the
velocity vector along this ray, the light-time-corrected line-of-sight from
the coordinate center, and indicates relative motion. A positive "deldot"
means the target center is moving away from the observer (coordinate center).
A negative "deldot" means the target center is moving toward the observer.
Units: AU and KM/S
Cnst =
Constellation ID; the 3-letter abbreviation for the name of the
constellation containing the target center's astrometric position,
as defined by IAU (1930) boundary delineation. See documentation
for list of abbreviations.
Computations by ...
Solar System Dynamics Group, Horizons On-Line Ephemeris System
4800 Oak Grove Drive, Jet Propulsion Laboratory
Pasadena, CA 91109 USA
Information: http://ssd.jpl.nasa.gov/
Connect : telnet://ssd.jpl.nasa.gov:6775 (via browser)
telnet ssd.jpl.nasa.gov 6775 (via command-line)
Author : Jon.D.Giorgini@jpl.nasa.gov
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