11 Parthenope

{{Short description|Main-belt asteroid}}

{{Use dmy dates|date=January 2020}}

{{Infobox planet

| minorplanet = yes

| background = #D6D6D6

| name = 11 Parthenope

| symbol = 24px or 24px (historical)

| image = 11 Parthenope VLT (2021), deconvolved.pdf

| image_size =

| caption = Deconvolved VLT-SPHERE image of Parthenope

| discoverer = Annibale de Gasparis

| discovery_site = Naples Obs.

| discovered = 11 May 1850

| mpc_name = (11) Parthenope

| alt_names =

| pronounced = {{IPAc-en|p|ɑːr|ˈ|θ|ɛ|n|ə|p|i}} {{respell|parth|EN|ə|pee}}Noah Webster (1884) A Practical Dictionary of the English Language

| named_after = Parthenopē

| adjectives = Parthenopean ({{IPAc-en|ˌ|p|ɑːr|θ|ə|n|ə|ˈ|p|iː|ə|n}} {{respell|PARTH|ə|nə|PEE|ən}})
Parthenopian ({{IPAc-en|ˌ|p|ɑːr|θ|ə|ˈ|n|oʊ|p|i|ə|n}} {{respell|PARTH|ə|NOH|pee|ən}}){{OED|Parthenopean}}, {{OED|Parthenopian}}

| mp_category = Main belt

| orbit_ref = {{cite web

|type=2024-11-29 last obs

|title=JPL Small-Body Database Browser: 11 Parthenope

|url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=11

|accessdate=20 December 2024}}

| epoch = 17.0 October 2024 (JD 2460600.5)

| semimajor = {{Convert|2.45337|AU|Gm|abbr=on}}

| perihelion = {{Convert|2.20942|AU|Gm|abbr=on}}

| time_periastron = 2024-Jan-12

| aphelion = {{Convert|2.69732|AU|Gm|abbr=on|lk=on}}

| eccentricity = 0.09943

| period = 3.84 yr (1403.6 d)

| inclination = 4.63153°

| asc_node = 125.506°

| arg_peri = 196.071°

| mean_anomaly = 71.503°

| avg_speed = 19.02 km/s

| flattening = 0.12{{efn|1=Flattening derived from the maximum aspect ratio (c/a): $f=1-\backslash frac\{c\}\{a\}$, where (c/a) = {{val|0.88|0.05}}.}}

| dimensions = {{val|156|x|152|x|138}} ± 6 km

| mean_diameter = {{val|149|2|u=km}}P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
{{val|142.887|1.008|u=km}}

| mass = {{val|5.5|0.4|e=18|u=kg}}
{{val|6.15|e=18|u=kg}}

| density = {{val|3.20|0.27|u=g/cm3}}
{{val|3.28|0.20|u=g/cm3}}

| surface_grav = 0.0578 m/s{{sup|2}}

| escape_velocity = 0.0941 km/s

| rotation = {{Convert|13.7204|h|d|abbr=on|lk=on}}
{{val|13.72204|0.00001|u=h}}

| axial_tilt = 73°

| spectral_type = S-type asteroid

| magnitude = 8.68{{cite web |title=AstDys (11) Parthenope Ephemerides |publisher=Department of Mathematics, University of Pisa, Italy |url=https://newton.spacedys.com/astdys/index.php?pc=1.1.3.1&n=11&oc=500&y0=2031&m0=7&d0=29&h0=00&mi0=00&y1=2031&m1=7&d1=29&h1=00&mi1=00&ti=1.0&tiu=days |accessdate=26 June 2010}} to 12.16

| abs_magnitude = 6.73
6.55

| pole_ecliptic_lat = {{val|17|4|u=deg}}

| pole_ecliptic_lon = {{val|312|2|u=deg}}

| albedo = 0.187 (calculated)
{{val|0.191|0.021}}

| angular_size = 0.178" to 0.057"

| single_temperature = ~174 K

| mean_motion = {{Deg2DMS|0.256484|sup=ms}} / day

| observation_arc = 63626 days (174.20 yr)

| uncertainty = 0

| moid = {{Convert|1.197|AU|Gm|abbr=on}}

| jupiter_moid = {{Convert|2.54059|AU|Gm|abbr=on}}

| tisserand = 3.483

}}

11 Parthenope ({{IPAc-en|p|ɑr|ˈ|θ|ɛ|n|ə|p|i}} {{respell|parth|EN|ə|pee}}) is a large, bright main-belt asteroid.

Parthenope was discovered by Annibale de Gasparis on 11 May 1850, the second of his nine asteroid discoveries. It was named after Parthenopē, one of the Sirens in Greek mythology, said to have founded the city of Naples. De Gasparis "used his utmost endeavours to realise a 'Parthenope' in the heavens, such being the name suggested by Sir John Herschel on the occasion of the discovery of Hygiea in 1849".{{cite journal| bibcode=1850MNRAS..10..144D| last=De Gasparis| first= Annibale| title=The New Planet Parthenope| journal= Monthly Notices of the Royal Astronomical Society| volume=10| pages=144–147 |date=May 1850| doi=10.1093/mnras/10.7.144| doi-access=free}} Two symbols were proposed for Parthenope: a fish and a star (in the pipeline for Unicode 17.0 as U+1CEC4 𜻄 16px) while such symbols were still in use, and later a lyre (in the pipeline for Unicode 17.0 as U+1F77A 🝺 16px) in lists of symbols. Both are obsolete.{{cite web |url=https://www.unicode.org/L2/L2023/23207-historical-asteroids.pdf |title=Unicode request for historical asteroid symbols |last1=Bala |first1=Gavin Jared |last2=Miller |first2=Kirk |date=18 September 2023 |website=unicode.org |publisher=Unicode |access-date=26 September 2023 |quote=}}{{cite web |url=https://unicode.org/alloc/Pipeline.html |title=Proposed New Characters: The Pipeline |author=Unicode |date= |website=unicode.org |publisher=The Unicode Consortium |access-date=6 November 2023 |quote=}}

There have been two observed Parthenopian occultations, on 13 February 1987, and 28 April 2006.

On 6 August 2008, during a perihelic opposition, Parthenope had an apparent magnitude of 8.8.

In 1988 a search for satellites or dust orbiting this asteroid was performed using the UH88 telescope at the Mauna Kea Observatories, but the effort came up empty.

Based upon a light curve that was generated from photometric observations of this asteroid at Pulkovo Observatory, it has a rotation period of 13.722 ± 0.001 hours and varies in brightness by 0.10 ± 0.0s in magnitude. The light curve displays three maxima and minima per cycle. The JPL Small-Body Database lists a rotation period of 13.7204 hours.