Template:Short description Template:Use dmy dates {{#invoke:infobox|infoboxTemplate | class = vcard | titleclass = fn org | title = 18 Melpomene | image = {{#invoke:InfoboxImage|InfoboxImage|image=18 Melpomene VLT (2021), deconvolved.pdf|upright={{#if:||1.1}}|alt=}} | caption = | headerstyle = {{#if:#D6D6D6|background-color:#D6D6D6|background-color:#E0CCFF}} | labelstyle = max-width:{{#if:||11em}}; | autoheaders = y

| header1 = Discovery

| label2 = Discovered by | data2 = John Russell Hind | label3 = Discovery site | data3 = | label4 = Discovery date | data4 = 24 June 1852 | label5 = Template:Longitem | data5 =

| header10 = {{#if:|Designations|Designations}}

| label11 = Template:Longitem | data11 = (18) Melpomene | label12 = Pronunciation | data12 = Template:IPAc-en<ref>Noah Webster (1884) A Practical Dictionary of the English Language</ref> | label13 = Template:Longitem | data13 = Melpomenē | label14 = Template:Longitem | data14 = | label15 = Template:Longitem | data15 = Main belt | label16 = Adjectives | data16 = Melpomenean Template:IPAc-en<ref>Tim Shephard (2014) Echoing Helicon</ref> | label17 = Symbol | data17 = File:Melpomene symbol (bold).svg (historical)

| header20 = Orbital characteristics{{#ifeq:|yes| (barycentric)}}<ref name=jpldata/>

| data21 = | data22 = {{#if:17.0 October 2024
(JD 2460600.5) |Epoch 17.0 October 2024
(JD 2460600.5)}} | data23 = {{#if: | Uncertainty parameter {{{uncertainty}}}}} | label24 = Observation arc | data24 = | label25 = Earliest precovery date | data25 = | label26 = {{#switch:{{{apsis}}} |apsis|gee|barion|center|centre|(apsis)=Apo{{{apsis}}} |Ap{{#if:|{{{apsis}}}|helion}}}} | data26 = Template:Convert | label27 = Peri{{#if:|{{{apsis}}}|helion}} | data27 = Template:Convert | label28 = Peri{{#if:|{{{apsis}}}|apsis}} | data28 = | label29 = {{#switch:{{{apsis}}} |helion|astron=Ap{{{apsis}}} |Apo{{#if:|{{{apsis}}}|apsis}}}} | data29 = | label30 = Periastron | data30 = | label31 = Apoastron | data31 = | label32 = Template:Longitem | data32 = Template:Convert | label33 = Template:Longitem | data33 = | label34 = Eccentricity | data34 = 0.21827 | label35 = Template:Longitem | data35 = Template:Cvt | label36 = Template:Longitem | data36 = | label37 = Template:Longitem | data37 = | label38 = Template:Longitem | data38 = 113.8711° | label39 = Template:Longitem | data39 = | label40 = Inclination | data40 = 10.132° | label41 = Template:Longitem | data41 = | label42 = Template:Longitem | data42 = 150.34° | label43 = Template:Longitem | data43 = | label44 = Template:Longitem | data44 = 2023-Sep-11 | label45 = Template:Longitem | data45 = 228.05° | label46 = Template:Nowrap | data46 = | label47 = Satellite of | data47 = | label48 = Group | data48 = | label49 = {{#switch: |yes|true=Satellites |Known satellites}} | data49 = | label50 = Star | data50 = | label51 = Earth MOID | data51 = Template:Convert | label52 = Mercury MOID | data52 = | label53 = Venus MOID | data53 = | label54 = Mars MOID | data54 = | label55 = Jupiter MOID | data55 = Template:Convert | label56 = Saturn MOID | data56 = | label57 = Uranus MOID | data57 = | label58 = Neptune MOID | data58 = | label59 = TJupiter | data59 = 3.543

| header60 = Proper orbital elements

| label61 = Template:Longitem | data61 = {{#if: |{{{p_semimajor}}} AU}} | label62 = Template:Longitem | data62 = | label63 = Template:Longitem | data63 = | label64 = Template:Longitem | data64 = {{#if: |{{{p_mean_motion}}} degTemplate:\yr}} | label65 = Template:Longitem | data65 = {{#if:|{{#expr:360/1 round 5}} yr
({{#expr:365.25*360/1 round 3}} d) }} | label66 = Template:Longitem | data66 = {{#if:|{{{perihelion_rate}}} arcsecTemplate:\yr }} | label67 = Template:Longitem | data67 = {{#if:|{{{node_rate}}} arcsecTemplate:\yr}}

| header70 = Template:Anchor{{#if:yes| Physical characteristics|Physical characteristics}}

| label71 = Dimensions | data71 = Template:Nowrap<ref name=Baer/>
(150 × 125 km)<ref name=Hubble1999/>
(150 × 170 km)<ref name=Hubble2005/> | label72 = Template:Longitem | data72 = Template:Val<ref name=VLT>Template:Cite journal</ref>
Template:Val<ref name=jpldata/> | label73 = Template:Longitem | data73 = | label74 = Template:Longitem | data74 = | label75 = Template:Longitem | data75 = | label76 = Flattening | data76 = 0.19Template:Efn | label77 = Circumference | data77 = | label78 = Template:Longitem | data78 = | label79 = Volume | data79 = | label80 = Mass | data80 = Template:Val<ref name=VLT/>
3.0Template:E kg<ref name=Baer/> | label81 = Template:Longitem | data81 = Template:Val<ref name=VLT/>
Template:Val<ref name=Baer/> | label82 = Template:Longitem | data82 = | label83 = Template:Longitem | data83 = | label84 = Template:Longitem | data84 = | label85 = Template:Longitem | data85 = Template:Cvt<ref name=jpldata/>
Template:Val<ref name=VLT/>
Template:Cvt<ref name=AstroSurf/> | label86 = Template:Longitem | data86 = | label87 = Template:Longitem | data87 = | label88 = Template:Longitem | data88 = 64°<ref name=VLT/> | label89 = Template:Longitem | data89 = | label90 = Template:Longitem | data90 = | label91 = Template:Longitem | data91 = Template:Val<ref name=VLT/> | label92 = Template:Longitem | data92 = Template:Val<ref name=VLT/> | label93 = {{#if:yes |Template:Longitem |Albedo}} | data93 = 0.221 (calculated)<ref name=VLT/>
0.223<ref name=ADA/>
0.181 ± 0.033<ref name=jpldata/> | label94 = Temperature | data94 =

| data100 = {{#if:|

{{#if:|}}{{#if:|}}{{#if:|}}{{#if:|}}
Surface temp. min mean max
{{{temp_name1}}}
{{{temp_name2}}}
{{{temp_name3}}}
{{{temp_name4}}}

}}

| label101 = Surface absorbed dose rate | data101 = | label102 = Surface equivalent dose rate | data102 = | label103 = Template:Longitem | data103 = S<ref name=jpldata/><ref name=VLT/> | label104 = Template:Longitem | data104 = | label105 = Template:Longitem | data105 = 7.5<ref name="Pasachoff1983"/> to 12.0 | label106 = Template:Longitem | data106 = 6.35<ref name=jpldata/>
6.51<ref name=VLT/> | label107 = Template:Longitem | data107 = 0.23" to 0.059"

| header110 = Atmosphere

| label111 = Template:Longitem | data111 = | label112 = Template:Longitem | data112 = | label113 = Composition by volume | data113 =

| below = {{#if:||Template:Reflist }}

}}{{#invoke:Check for unknown parameters|check|unknown=Template:Main other|preview=Page using Template:Infobox planet with unknown parameter "_VALUE_"|ignoreblank=y| abs_magnitude | adjective | adjectives | albedo | allsatellites | alt_names | angular_dist | angular_size | aphelion | apoapsis | apsis | apoastron | arg_peri | asc_node | atmosphere | atmosphere_composition | atmosphere_ref | avg_speed | axial_tilt | background | barycentric | bgcolour | caption | circumference | declination | density | dimensions | discovered | discoverer | discovery_method | discovery_ref | discovery_site | earliest_precovery_date | eccentricity | epoch | equatorial_radius | escape_velocity | exosolar planets | extrasolarplanet | family | flattening | group | image | image_alt | image_scale | inclination | jupiter_moid | label_width | long_periastron | magnitude | mars_moid | mass | max_temp_1 | max_temp_2 | max_temp_3 | max_temp_4 | mean_anomaly | mean_diameter | mean_motion | mean_orbit_radius | mean_radius | mean_temp_1 | mean_temp_2 | mean_temp_3 | mean_temp_4 | mercury_moid | min_temp_1 | min_temp_2 | min_temp_3 | min_temp_4 | minorplanet | moid | moment_of_inertia_factor | mp_category | mp_name | mpc_name | name | named_after | neptune_moid | node_rate | note | observation_arc | orbit_diagram | orbit_ref | p_eccentricity | p_inclination | p_mean_motion | p_orbit_ref | p_semimajor | periapsis | periastron | perihelion | perihelion_rate | period | physical_ref | polar_radius | pole_ecliptic_lat | pole_ecliptic_lon | pronounce | pronounced | right_asc_north_pole | rot_velocity | rotation | satellite_of | satellites | saturn_moid | scale_height | semi-amplitude | semimajor | sidereal_day | single_temperature | spectral_type | star | surface_area | surface_grav | surface_pressure | surface_absorbed_dose_rate | surface_equivalent_dose_rate | symbol | synodic_period | temp_name1 | temp_name2 | temp_name3 | temp_name4 | time_periastron | tisserand | uncertainty | uranus_moid | venus_moid | volume }}

18 Melpomene is a large, bright main-belt asteroid that was discovered by J. R. Hind on 24 June 1852,<ref name="IAU_MPC"/> and named after Melpomenē, the Muse of tragedy in Greek mythology. Its historical symbol was a dagger over a star; as of 2023 it was in the pipeline for Unicode 17.0 as U+1CECB 𜻋 (File:Melpomene symbol (fixed width).svg).<ref name=astunicode>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name=pipeline>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Melpomene is classified as an S-type asteroid and is composed of silicates and metals. This asteroid is orbiting the Sun at a distance of Template:Cvt with a period of Template:Convert and an eccentricity (ovalness) of 0.22. The orbital plane is tilted at an angle of 10.1° to the plane of the ecliptic.<ref name=jpldata/>

Melpomene occulted the star SAO 114159 on 11 December 1978. A possible Melpomenean satellite with a diameter of at least 37 km was detected. The satellite candidate received a provisional designation S/1978 (18) 1.<ref name=IAUC3315/> 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.<ref name="Gradie1988"/> Melpomene was observed with the Hubble Space Telescope in 1993. It was able to resolve the asteroid's slightly elongated shape, but no satellites were detected.<ref name=Hubble1999/>

Melpomene has been studied by radar.<ref name="detected"/> Photometric observations during 2012 provided a rotation period of Template:Val with a brightness variation of Template:Val in magnitude, which is consistent with previous studies.<ref name=Pilcher2013/> It has a mean diameter of Template:Val.<ref name=VLT/><ref name=jpldata/>

Melpomene can reach an apparent magnitude of +7.9 at a favorable opposition near perihelion, such as occurred in September 2002 when it was Template:Convert from Earth.<ref name="Horizons2002"/>

NotesEdit

Template:Notelist

ReferencesEdit

Template:Reflist

External linksEdit

Template:Minor planets navigator {{#invoke:Navbox|navbox}} Template:Authority control

vec:Lista de asteroidi#18 Melpòmene