28P/Neujmin
{{Short description|Periodic comet}}
{{Use dmy dates|date=May 2025}}
{{Infobox comet
| name=28P/Neujmin
| image= Comet Neujmin 1913 by E.E. Barnard.jpg
| caption = Sketch of Comet Neujmin 1 as seen by Edward E. Barnard from the Yerkes Observatory on 9 September 1913.
| discoverer = Grigory Neujmin
| discovery_date = 3 September 1913
| mpc_name = P/1913 R2, P/1931 S1
| designations = {{unbulleted|Neujmin 1|1913 III, 1931 I, 1948 XIII|1966 VI, 1984 XIX}}
| orbit_ref = {{r|jpldata|MPC}}
| epoch = 17 October 2024 (JD 2460600.5)
| observation_arc = 110.58 years
| obs = 1,276
| perihelion = 1.585 AU
| aphelion = 12.38 AU
| semimajor = 6.983 AU
| eccentricity = 0.77297
| period = 18.45 years
| inclination = 14.299°
| asc_node = 346.39°
| arg_peri = 347.47°
| mean = 70.299°
| tjup = 2.168
| Earth_moid = 0.574 AU
| Jupiter_moid = 0.960 AU
| physical_ref = {{r|jpldata|Delahodde_2001}}
| dimensions = {{cvt|21.4|km|mi}}
| rotation = {{val|12.75|0.03}} hours
| albedo = 0.025
| M1 = 13.2
| M2 =
| last_p = 11 March 2021{{cite web
|date=2004-09-07
|title=28P/Neujmin 1
|publisher=Seiichi Yoshida's Comet Catalog
|author=Seiichi Yoshida
|url=http://www.aerith.net/comet/catalog/0028P/index.html
|access-date=2010-02-26}}{{cite web
|date=2001-05-01
|title=28P/Neujmin 1 (NK 798)
|publisher=OAA Computing and Minor Planet Sections
|author=Syuichi Nakano
|author-link=Syuichi Nakano
|url=https://www.oaa.gr.jp/~oaacs/nk/nk798.htm
|access-date=2010-02-26}}
}}
28P/Neujmin, also known as Neujmin 1, is a large periodic comet in the Solar System. With a perihelion distance (closest approach to the Sun) of {{convert|1.5|AU|e6km|abbr=unit}}, this comet does not make close approaches to the Earth.{{r|jpldata}}
Orbital and physical characteristics
The comet nucleus is estimated to be {{cvt|21.4|km|mi}} in diameter with a low albedo of 0.025.{{r|jpldata}} Since 28P has such a large nucleus, it became brighter than the 20th magnitude in early 2019, roughly 2 years before coming to perihelion. When it came to opposition in May 2020, when it was still {{convert|3.5|AU|e6km|abbr=unit}} from the Sun, it had an apparent magnitude around 16.9. But during the 2021 perihelion passage the comet was on the opposite side of the Sun as the Earth. The comet is not known for bright outbursts of activity.
References
{{Reflist|refs=
| author1= C. E. Delahodde
| author2= K. J. Meech
| author3= O. R. Hainaut
| author4= E. Dotto
| title= Detailed phase function of comet 28P/Neujmin 1
| journal= Astronomy & Astrophysics
| year= 2001
| volume= 376
| issue= 2
| pages= 672–685
| bibcode= 2001A&A...376..672D
| doi= 10.1051/0004-6361:20011028
| doi-access= free }}
| title= 28P/Neujmin 1 – JPL Small-Body Database Lookup
| url= https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=28P
| website= ssd.jpl.nasa.gov
| publisher= Jet Propulsion Laboratory
| access-date= 25 February 2010 }}
| title= 28P/Neujmin Orbit
| url= https://www.minorplanetcenter.net/db_search/show_object?object_id=28P
| publisher= Minor Planet Center
| access-date= 12 September 2021 }}
|title=Horizons Batch for 28P/Neujmin 1 (90000386) on 2039-Jul-23
|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=%2790000386%27&START_TIME=%272039-Jul-18%27&STOP_TIME=%272039-Jul-30%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27
|accessdate=2023-05-02}} (JPL#74/Soln.date: 2023-Mar-29)
}}
External links
- {{JPL Small Body|id=1000063}}
- [http://cometography.com/pcomets/028p.html 28P at Kronk's Cometography]
- [http://www.aerith.net/comet/catalog/0028P/index.html 28P/Neujmin 1] – Seiichi Yoshida @ aerith.net
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