18D/Perrine–Mrkos

{{For|other comets discovered by Antonín Mrkos|Comet Mrkos (disambiguation){{!}}Comet Mrkos}}

{{Infobox comet

| name=18D/Perrine–Mrkos

| image= D591 1909-10-11 18DPerrine-Mrkos.jpg

| caption = The comet on 11 October 1909 by the Heidelberg-Königstuhl State Observatory

| discoverer=Charles Dillon Perrine & Antonín Mrkos

| discovery_date=December 9, 1896

| designations=1896 X1; 1896 VII;
1896g; 1909 P1;
1909 III; 1909b;
1955 U1; 1955 VII;
1955i; 1962 I;
1961h; 1968 VIII;
1968h

| epoch=2002-09-03 (JD 2452520.5)

| semimajor=3.5705 AU

| perihelion=1.2872 AU

| aphelion=5.8537 AU

| eccentricity=0.6395

| period=6.75 a

| inclination=17.864°

| last_p=2017 Feb. 26?
(unobserved)

| next_p=≈2025-Jan-01?
(Lost since 1969)

}}

18D/Perrine–Mrkos is a periodic comet in the Solar System, originally discovered by the American-Argentine astronomer Charles Dillon Perrine (Lick Observatory, California, United States) on December 9, 1896. For some time it was thought to be a fragment of Biela's Comet.

It was considered lost after the 1909 appearance, but was rediscovered by the Czech astronomer Antonín Mrkos (Skalnate Pleso Observatory, Slovakia) on October 19, 1955, using ordinary binoculars, it was later confirmed as 18D by Leland E. Cunningham (Leuschner Observatory, University of California, Berkeley).

The comet was last observed during the 1968 perihelion passage when it passed {{convert|0.3144|AU|km mi|abbr=on|lk=on}} from the Earth. The comet has not been observed during the following perihelion passages:

1975 Aug. 2
1982 May 16
1989 Feb. 28
1995 Dec. 6 (apmag 19?)
2002 Sept.10 (apmag 20?)
2009 Apr. 17 (apmag 24?)
2017 Feb. 26 (apmag 24?)

The next predicted perihelion passage would be on 2025-Jan-01 but the comet is currently considered lost as it has not been seen since Jan 1969.

References

{{Reflist

| refs =

{{Cite web

|first=Gary W.

|last=Kronk

|author-link=Gary W. Kronk

|year=2001–2005

|title=18D/Perrine-Mrkos

|url=http://cometography.com/pcomets/018d.html

|access-date=2006-06-09

|archive-url=https://web.archive.org/web/20010405095745/http://cometography.com/

|archive-date=2001-04-05

|url-status=bot: unknown

}}()

{{cite web

|type=1968-12-26 last obs

|title=JPL SBDB: 18D/Perrine-Mrkos

|url=https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=18D&view=OPC

|archive-url=https://web.archive.org/web/20201114172327/https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=18D;cad=1

|archive-date=2020-11-14

|url-status=live }}

{{cite web

|date=2009-09-19

|title=18D/Perrine-Mrkos

|publisher=Seiichi Yoshida's Comet Catalog

|author=Seiichi Yoshida

|url=http://www.aerith.net/comet/catalog/0018D/index.html

|access-date=2012-02-22}}

{{cite web

|title=18D/Perrine–Mrkos Orbit

|url=https://www.minorplanetcenter.net/db_search/show_object?object_id=18D

|publisher=Minor Planet Center

|access-date=2019-02-26}}

{{cite web

|title=Horizons Batch for 18D/Perrine-Mrkos (90000290) on 2025-Jan-01

|publisher=JPL Horizons

|type=Perihelion occurs when rdot flips from negative to positive

|url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%2790000290%27&START_TIME=%272025-Jan-01%2022:00%27&STOP_TIME=%272025-Jan-02%27&STEP_SIZE=%2710%20minutes%27&QUANTITIES=%2719%27

|accessdate=2023-02-11}} (JPL#J682/18 Soln.date: 2002-Feb-22)

}}

External links

[http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=18D;orb=1 Orbital simulation] from JPL (Java) / [http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=18D Horizons Ephemeris]
[http://cometography.com/pcomets/018d.html 18D at Kronk's Cometography]
[http://jcometobs.web.fc2.com/pcmtn/0018d.htm 18D at Kazuo Kinoshita's Comets]
[http://www.aerith.net/comet/catalog/0018D/index.html 18D at Seiichi Yoshida's Comet Catalog]
[http://www.oaa.gr.jp/~oaacs/nk/nk835.htm NK 835 18D/Perrine-Mrkos] – Syuichi Nakano (2002)

Category:Periodic comets