128 Nemesis

{{Infobox planet

| minorplanet=yes

| image=128 Nemesis VLT (2021), deconvolved.pdf

| background=#D6D6D6

| name=128 Nemesis

| discovery_ref=

| discoverer=James Craig Watson

| discovered=25 November 1872

| mpc_name=(128) Nemesis

| alt_names=A872 WA; {{mp|1952 HW|1}}

| pronounced={{IPAc-en|ˈ|n|ɛ|m|ᵻ|s|ɪ|s}}{{OED|Nemesis}}

| adjective=Nemesian {{IPAc-en|n|ə|ˈ|m|iː|ʒ|(|i|)|ə|n}}Hornum (1993) Nemesis, the Roman state and the gamesPeery (1963) Studies in the Renaissance, vol. 10

| named_after=Nemesis

| mp_category=main-belt{{·}}Nemesis

| orbit_ref =

| epoch = 23 March 2018 (JD 2458200.5)

| uncertainty = 0

| observation_arc = 144.93 yr (52,934 d)

| aphelion = {{convert|3.0996|AU|Gm|adj=ri2|2|abbr=on|lk=on}}

| perihelion = {{convert|2.3998|AU|Gm|adj=ri2|2|abbr=on}}

| semimajor = {{convert|2.7497|AU|Gm|adj=ri2|2|abbr=on}}

| eccentricity = 0.1272

| period = {{convert|1665|days|years|2|order=flip}}

| mean_anomaly = 345.49°

| mean_motion = {{Deg2DMS|0.2162|sup=ms}} / day

| inclination = 6.2453°

| asc_node = 76.243°

| arg_peri = 303.82°

| mean_diameter = {{val|163|5|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|162.5|1.3|ul=km}}
{{val|184.2|5.2|u=km}}

| flattening = 0.17{{efn|1=Flattening derived from the maximum aspect ratio (c/a): $f=1-\frac{c}{a}$ , where (c/a) = {{val|0.83|0.04}}.}}

| mass = {{val|3.4|1.7|e=18|u=kg}}
{{val|6.0|2.6|e=18|ul=kg}}

| density = {{val|1.5|0.8|u=g/cm3}}
{{val|1.82|0.79|u=g/cm³}}

| rotation = {{Convert|77.81|h|d|abbr=on|lk=on}}
{{Convert|38.9325|h|d|abbr=on|lk=on}}

| albedo = 0.067 (calculated)
{{val|0.067|0.005}}

| spectral_type = Tholen {{=}} C
SMASS {{=}} C

| abs_magnitude=7.70

}}

128 Nemesis is a large 180 km main-belt asteroid, of carbonaceous composition. It rotates rather slowly, taking about 78 hours to complete one rotation. Nemesis is the largest member of the Nemesian asteroid family bearing its name. It was discovered by J. C. Watson on 25 November 1872, and named after Nemesis, the goddess of retribution in Greek mythology.

file:128 Nemesis (orbit).gif

This object is orbiting the Sun with a period of {{convert|1665|days|years|2|disp=out|abbr=off}} and an eccentricity (ovalness) of 0.13. The orbital plane is inclined by 6.2° to the plane of the ecliptic. It is categorized as a C-type asteroid, indicating a primitive carbonaceous composition. Based on IRAS data Nemesis is about 188 km in diameter and is around the 33rd largest main-belt asteroid, while WISE measurements yield a size of ~163 km. The 77.81‑hour rotation period is the second longest for an asteroid more than 150 km in diameter.

Between 2005 and 2021, 128 Nemesis has been observed to occult eight stars.

Notes

References

{{reflist|refs=

{{cite web

|type = 2017-10-31 last obs.

|title = JPL Small-Body Database Browser: 128 Nemesis

|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2000128

|publisher = Jet Propulsion Laboratory

|accessdate = 14 September 2018}}

{{cite web

|title = 128 Nemesis

|work = Minor Planet Center

|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=128

|accessdate = 14 September 2018}}

{{cite journal

|display-authors = 6

|first1 = Joseph R. |last1 = Masiero

|first2 = T. |last2 = Grav

|first3 = A. K. |last3 = Mainzer

|first4 = C. R. |last4 = Nugent

|first5 = J. M. |last5 = Bauer

|first6 = R. |last6 = Stevenson

|first7 = S. |last7 = Sonnett

|date = August 2014

|title = Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos

|journal = The Astrophysical Journal

|volume = 791

|issue = 2

|page = 11

|bibcode = 2014ApJ...791..121M

|doi = 10.1088/0004-637X/791/2/121

|arxiv = 1406.6645

|s2cid = 119293330 }}

{{citation

| title=New Photometric Observations of 128 {{sic|Nemisis|nolink=y}}, 249 Ilse, and 279 Thule

| last1=Pilcher | first1=Frederick

| journal=The Minor Planet Bulletin

| volume=42 | issue=3 | pages=190−192 | date=July 2015

| bibcode=2015MPBu...42..190P | postscript=. }}

{{cite web

|title=JPL Small-Body Database Search Engine: asteroids and orbital class (IMB or MBA or OMB) and diameter > 188.1 (km)

|publisher=JPL's Solar System Dynamics Group

|url=http://ssd.jpl.nasa.gov/sbdb_query.cgi?obj_group=all;obj_kind=ast;obj_numbered=all;ast_orbit_class=IMB;ast_orbit_class=MBA;ast_orbit_class=OMB;OBJ_field=0;ORB_field=0;c1_group=OBJ;c1_item=Ap;c1_op=%3E;c1_value=188.1;table_format=HTML;max_rows=500;format_option=comp;c_fields=AcApAiBhBgBjBkBlBiBnBs;.cgifields=format_option;.cgifields=obj_kind;.cgifields=obj_group;.cgifields=obj_numbered;.cgifields=ast_orbit_class;.cgifields=table_format;.cgifields=com_orbit_class&query=1&c_sort=ApA

|accessdate=2012-04-17}}

{{Citation

| first1 = B.

| last1 = Carry

| title = Density of asteroids

| journal = Planetary and Space Science

| volume = 73

| pages = 98–118

| date = December 2012

| issue = 1

| doi = 10.1016/j.pss.2012.03.009

| bibcode = 2012P&SS...73...98C

| postscript= .

|arxiv = 1203.4336 | s2cid = 119226456

}} See Table 1.

{{Citation

| last1 = Scaltriti

| first1 = F.

| last2 = Zappala

| first2 = V.

| last3 = Schober

| first3 = H. J.

| title = The rotations of 128 Nemesis and 393 Lampetia - The longest known periods to date

| journal = Icarus

| volume = 37

| pages = 133–141

| date = January 1979

| issue = 1

| doi = 10.1016/0019-1035(79)90121-0

| bibcode = 1979Icar...37..133S

| postscript= .}}

{{Citation

|last1=DeMeo

|first1=Francesca E.

|last2=Binzel

|first2=Richard P.

|last3=Slivan

|first3=Stephen M.

|last4=Bus

|first4=Schelte J.

|display-authors=1

|title=An extension of the Bus asteroid taxonomy into the near-infrared

|journal=Icarus

|volume=202

|issue=1

|pages=160–180

|date=July 2009

|doi=10.1016/j.icarus.2009.02.005

|bibcode=2009Icar..202..160D

|url=http://www.tara.tcd.ie/bitstream/2262/43276/1/PEER_stage2_10.1016%252Fj.icarus.2009.02.005.pdf

|accessdate=2013-04-08

|postscript=.

|url-status=dead

|archiveurl=https://web.archive.org/web/20140317200310/https://www.tara.tcd.ie/bitstream/2262/43276/1/PEER_stage2_10.1016/j.icarus.2009.02.005.pdf

|archivedate=2014-03-17

}} See appendix A.

{{cite web

|title=JPL Small-Body Database Search Engine: diameter > 150 (km) and rot_per > 24 (h)

|publisher=JPL Solar System Dynamics

|url=http://ssd.jpl.nasa.gov/sbdb_query.cgi?obj_group=all;obj_kind=all;obj_numbered=all;OBJ_field=0;ORB_field=0;combine_mode=AND;c1_group=OBJ;c1_item=Ap;c1_op=%3E;c1_value=150;c2_group=OBJ;c2_item=As;c2_op=%3E;c2_value=24;table_format=HTML;max_rows=50;format_option=comp;c_fields=AcBhBgBjBiBnBsAiApAs;.cgifields=format_option;.cgifields=ast_orbit_class;.cgifields=combine_mode;.cgifields=table_format;.cgifields=obj_kind;.cgifields=obj_group;.cgifields=obj_numbered;.cgifields=com_orbit_class&query=1&c_sort=AsD

|accessdate=2015-06-06}}

}}

External links

{{AstDys|128}}
{{JPL small body}}
{{YouTube|0_GTC15PvJ8|Nemesis found! (2013)}}

{{Minor planets navigator |127 Johanna |number=128 |129 Antigone}}

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Category:Discoveries by James Craig Watson

Category:Named minor planets

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