Asteroid 11 Parthenope is a large, main-belt asteroid with a diameter of approximately 162 kilometers. It was discovered on May 11, 1850, by Italian astronomer Annibale de Gasparis and named after the Siren of Greek mythology, Parthenope. The asteroid orbits the Sun between Mars and Jupiter, with a semi-major axis of approximately 2.45 astronomical units (AU) and an orbital period of about 4.04 years. Parthenope's orbit is relatively eccentric and inclined compared to other asteroids in the main belt. It rotates slowly, with a rotation period of about 16 hours. Parthenope is also classified as a C-type asteroid, indicating that its surface is likely rich in carbonaceous materials.

Find it in the Sky

Chose a date & time and view the position of asteroid 11 Parthenope in the sky on our interactive planetarium.

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Asteroid 11 Parthenope

Above the horizon. Rise: 5:31 | Tran: 13:28 | Set: 21:25

Alt: 14.29° Az: 73.15° Direction: East-North-East

Asteroid 11 Parthenope is in the constellation of Gemini, at a distance of 546,241,848.0 kilometers from Earth. The current Right Ascension is 06h 59m 16s and the Declination is +21° 35’ 45” (apparent coordinates). The magnitude of asteroid 11 Parthenope is 11.92.

Finder Charts

The sky charts below show, at different resolutions, the position of asteroid 11 Parthenope in the sky. Click on each chart to access the interactive star map tool.

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Star map showing the position of asteroid 11 Parthenope in the constellation of Gemini on F, d Y. Field of view: 50x30 degrees. View interactive star map.

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Star map showing the position of asteroid 11 Parthenope in the constellation of Gemini on F, d Y. Field of view: 15x9 degrees. View in interactive star map.

The following map uses photographic imagery from the Digitized Sky Survey (DSS) to realistically visualize the precise position of asteroid 11 Parthenope against the stars in the background. The horizontal size of the map measures 60 arcminutes. Click on the image to access a more detailed full-screen view.

11 Parthenope
RA: 06h 57m 45s
Dec: +21° 37’ 54”

Simplified high-resolution deep sky chart showing the current position of asteroid 11 Parthenope. Field of view: 60 x 40 arcminutes. Go to the dedicated page

Equatorial Coordinates

Apparent

Right Ascension 06h 59m 16s

Declination +21° 35’ 45”

Hour Angle 17h 43m 43s

Sidereal Time 00h 43m 00s

J2000

Right Ascension 06h 57m 45s

Declination +21° 37’ 54”

Additional Information

Constellation Gemini

Magnitude 11.92

Rise and Set Times

The following table lists today's rise, transit and set times of asteroid 11 Parthenope from Greenwich, UK (all times relative to the local timezone Europe/London):

Azimuth: 68.4° RISE 5:31

Max altitude: 60.1° TRANSIT 13:28

Azimuth: 291.6° SET 21:25

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 11 Parthenope from Earth is currently 546,241,848.0 kilometers, equivalent to 3.6514012228 Astronomical Units. Light takes 30m 22.067s to travel from asteroid 11 Parthenope and arrive to us.

Distance Km 546,241,848.0

Distance AU 3.6514012228

Light Travel Time 30m 22.067s

The following graph shows the distance of asteroid 11 Parthenope from Earth as a function of time. In the chart the distance is measured in Astronomical Units and the data is sampled with an interval of 1 day.

Chart of the distance of asteroid 11 Parthenope from Earth in Astronomical Units (au)
Note: The values in this chart may not be entirely accurate around the time of closest approach for objects passing very close to Earth at high speed (e.g., Near-Earth Objects).

The value of the distance of 11 Parthenope from Earth is also available as a real time updated value in the live position tracker.

Closest Approach to Earth

In the period between January 1, 1900 and December 31, 2099, the closest approach of asteroid 11 Parthenope to Earth will happen on Monday 11 August 2081 at a distance of 1.187050 Astronomical Units, or 177,580,172 kilometers:

Date Monday 11 August 2081

Distance Kilometers 177,580,172

Distance AU 1.187050

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

Light Curve

The following chart shows the light curve of asteroid 11 Parthenope, i.e., its apparent magnitude as a function of time. The curve is calculated using the latest ephemerides provided by JPL Horizons. The magnitude data is sampled with the interval of 2 days. Because of this sampling, inaccuracies may occur for objects that have large variations of brightness over a few days. For comets, large discrepancies can arise between the calculated brightness and the observations due to their highly dynamic, and not always precisely predictable, behavior.

Chart of the magnitude of asteroid 11 Parthenope as a function of time

Orbital Elements

The following table lists the orbital elements of asteroid 11 Parthenope at epoch February, 24 2023 00:00 UTC (JD: 2460000.5). Source: JPL Small-Body Database

Element	Symbol	Value
Orbit eccentricity	e	0.09941749
Orbit inclination	i	4.63133416°
Perihelion distance	q	2.20919106 AU 330,490,279 km
Aphelion distance	Q	2.69694697 AU 403,457,525 km
Semi-major axis	a	2.45306902 AU 366,973,902 km
Orbital period	period	3.8421 years 1,403.3406 days
Date of perihelion transit	Tp	January 11, 2024 2,460,320.6847 JD
Next perihelion transit		November 14, 2027 2,461,724.0253 JD
Argument of perihelion	peri	195.73724774726°
Longitude of the ascending node	node	125.52086857436°
Mean anomaly	M	277.86276820831°
Mean motion	n	0.25653075°/day

Orbit Visualization

The following chart is a 3D animated visualization of the orbit of asteroid 11 Parthenope relative to the other major objects in the Solar System. You can access more advanced features using our 3D Solar System Viewer.

Physical Properties

The table below lists the known key physical properties of asteroid 11 Parthenope. The source for this data is the JPL Small-Body Database.

Physical Parameter	Value	Relative to Earth
Diameter	153.33 km	0.0120
Sideral Rotation	13.7204 hours	0.5732
Absolute Magnitude	6.55
Geometric Albedo	0.1803

15 Days Ephemeris

The following table lists the ephemerides of asteroid 11 Parthenope 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
Jun 22 2025	06h 46m 04s	+21° 47’ 00”	11.99	Gemini
Jun 23 2025	06h 47m 53s	+21° 45’ 42”	11.98	Gemini
Jun 24 2025	06h 49m 43s	+21° 44’ 19”	11.97	Gemini
Jun 25 2025	06h 51m 32s	+21° 42’ 52”	11.96	Gemini
Jun 26 2025	06h 53m 21s	+21° 41’ 20”	11.95	Gemini
Jun 27 2025	06h 55m 10s	+21° 39’ 43”	11.94	Gemini
Jun 28 2025	06h 56m 59s	+21° 38’ 01”	11.93	Gemini
Jun 29 2025	06h 58m 48s	+21° 36’ 14”	11.92	Gemini
Jun 30 2025	07h 00m 37s	+21° 34’ 22”	11.91	Gemini
Jul 01 2025	07h 02m 26s	+21° 32’ 26”	11.89	Gemini
Jul 02 2025	07h 04m 15s	+21° 30’ 25”	11.88	Gemini
Jul 03 2025	07h 06m 04s	+21° 28’ 19”	11.86	Gemini
Jul 04 2025	07h 07m 53s	+21° 26’ 08”	11.85	Gemini
Jul 05 2025	07h 09m 41s	+21° 23’ 53”	11.83	Gemini

Ephemeris Calculator

Compute the position of asteroid 11 Parthenope for any date and time between January 1, 1900 and December 31, 2099 and display the results on an interactive star map.