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Dwarf Planets and Asteroids » 

Asteroid 20 Massalia

Above the horizon.  Rise: 8:53 | Tran: 15:41 | Set: 22:31
Alt: 43.36°   Az: 143.86°   Direction: South-East

Asteroid 20 Massalia was discovered by astronomer Annibale de Gasparis on September 19, 1852. It is named after the ancient Greek city of Massalia, which is now modern-day Marseille, France. Massalia is a relatively large and bright asteroid, with a diameter of about 146 kilometers. It is classified as an S-type asteroid, meaning that it is composed primarily of silicate rock and metal. Massalia has a relatively short rotation period of just over 6 hours and orbits the Sun every 4.3 years at an average distance of 2.41 astronomical units (AU).

Asteroid 20 Massalia is in the constellation of Pisces, at a distance of 385,186,830.0 kilometers from Earth. The current Right Ascension is 01h 37m 13s and the Declination is +09° 52’ 44” (apparent coordinates). The magnitude of Asteroid 20 Massalia is 11.29 (data provided by JPL Horizons).

Finder Charts

Map showing Asteroid 20 Massalia in Pisces on February, 18 2025. Field of view: 50x30 degrees
View interactive star map
Sky map showing Asteroid 20 Massalia in Pisces on February, 18 2025. Field of view: 15x9 degrees. View in interactive sky chart

High precision deep sky finder chart, 60 arcmin wide, showing where Asteroid 20 Massalia is right now. Click on the image to see a more detailed fullscreen tracker view.

20 Massalia
RA: 01h 35m 53s
Dec: +09° 45’ 04”
Deep sky finder chart for Asteroid 20 Massalia. Field of view: 60x40 arcmins. View in deep sky object tracker

Also check out Where is Asteroid 20 Massalia?, a page that provides all the information needed to find Asteroid 20 Massalia in the sky and additional links to sky charts.

Celestial Coordinates

Apparent

01h 37m 13s
+09° 52’ 44”
22h 16m 48s
23h 54m 02s

J2000

01h 35m 53s
+09° 45’ 04”

Additional Information

Pisces
11.29

Rise and Set Times

Today's rise, transit and set times of Asteroid 20 Massalia from Greenwich, UK (all times relative to the local timezone Europe/London):

Azimuth: 80.2°
Max altitude: 48.4°
Azimuth: 279.9°
  • 20 Massalia is above the horizon from Greenwich, UK.
  • Right now it is placed in the South-East direction at an altitude of 43.36° above the horizon.
  • Given its current magnitude, 20 Massalia is visible with the help of a binocular with a 70-80mm aperture or a small telescope.
  • Go to interactive sky chart

If you need to access this information frequently for your observations, you can create a simple customized Quick Access page, so that you can easily bookmark it in your browser favorites or add a shortcut to your mobile phones' home screen.

Distance from Earth

The distance of Asteroid 20 Massalia from Earth is currently 385,186,830.0 kilometers, equivalent to 2.5748149235 Astronomical Units. Light takes 21m 24.845s to travel from Asteroid 20 Massalia and arrive to us.

385,186,830.0
2.5748149235
21m 24.845s

The following chart shows the distance of Asteroid 20 Massalia from Earth as a function of time. In the chart the distance data is measured in Astronomical Units and sampled with an interval of 1 day.

Chart of the distance of Asteroid 20 Massalia from Earth in Astronomical Units (au)

The value of the reported distance might be somewhat inaccurate around the times of closest approach for objects passing extremely close to Earth. The value of the distance of 20 Massalia from Earth is also available as a real time updated value in the Live Position and Data Tracker.

Closest Approach

Between 1 January 1900 and 31 December 2099, the closest approach of Asteroid 20 Massalia to Earth happens on Mon Jan 6 2048 at a distance of 1.077062 Astronomical Units, or 161,126,212 kilometers:

Mon Jan 6 2048
161,126,212
1.077062

NOTE: values for the closest approach are computed with a sampling interval of 1 day.

Light Curve

The following chart is the predicted light curve (visual magnitude as a function of time) of Asteroid 20 Massalia, according to the most recent ephemerides data. Magnitude data is sampled with a 2 days interval and there might be inaccuracies for objects changing brightness very rapidly during the course of a few days. For comets there could be large discrepancies between the observed and predicted brightness because of their highly dynamic behaviour.

Chart of the magnitude of Asteroid 20 Massalia as a function of time

Orbital Elements

The following table lists the orbital elements of Asteroid 20 Massalia at epoch 24 February 2023 00:00 UTC (JD: 2460000.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.14328810
Orbit inclination i 0.70919118°
Perihelion distance q 2.06345443 AU
308,688,390 km
Aphelion distance Q 2.75369454 AU
411,946,840 km
Semi-major axis a 2.40857448 AU
360,317,615 km
Orbital period period 3.7381 years
1,365.3329 days
Date of perihelion transit Tp 2021-Nov-04 02:43:02
2,459,522.6132 JD
Next perihelion transit 2025-Jul-31 10:42
2,460,887.9461 JD
Argument of perihelion peri 257.50682680841°
Longitude of the ascending node node 205.9677482734°
Mean anomaly M 126.00534306121°
Mean motion n 0.26367196°/day

Orbit Visualization

Orbit Diagram of Asteroid 20 Massalia
View Asteroid 20 Massalia in the 3D Solar System Simulator

Physical Data

The following shows the known values of the most important physical parameters of Asteroid 20 Massalia. Source: JPL Small-Body Database

Physical Parameter Value Relative to Earth
Diameter 145.5 km 0.0114
Sideral Rotation 8.0980 hours 0.3383
Absolute Magnitude 6.5
Geometric Albedo 0.2096

15 Days Ephemeris

The following table lists the ephemerides of Asteroid 20 Massalia computed for the past and next 7 days, with a 24 hours interval. Apparent celestial coordinates are provided.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
2025 Feb 11 01h 24m 31s +08° 39’ 39” 11.27 Pisces
2025 Feb 12 01h 26m 09s +08° 49’ 13” 11.27 Pisces
2025 Feb 13 01h 27m 49s +08° 58’ 49” 11.28 Pisces
2025 Feb 14 01h 29m 28s +09° 08’ 27” 11.28 Pisces
2025 Feb 15 01h 31m 09s +09° 18’ 04” 11.28 Pisces
2025 Feb 16 01h 32m 49s +09° 27’ 44” 11.29 Pisces
2025 Feb 17 01h 34m 31s +09° 37’ 23” 11.29 Pisces
2025 Feb 18 01h 36m 13s +09° 47’ 05” 11.29 Pisces
2025 Feb 19 01h 37m 56s +09° 56’ 46” 11.29 Pisces
2025 Feb 20 01h 39m 39s +10° 06’ 29” 11.30 Pisces
2025 Feb 21 01h 41m 22s +10° 16’ 11” 11.30 Pisces
2025 Feb 22 01h 43m 08s +10° 25’ 54” 11.30 Pisces
2025 Feb 23 01h 44m 52s +10° 35’ 38” 11.30 Pisces
2025 Feb 24 01h 46m 38s +10° 45’ 22” 11.30 Pisces

Additional Resources