238P/Read
{{Short description|Main-belt comet}}
{{Infobox planet
| background = #FFE0C2
| name = 238P/Read
P/2005 U1
| image = Comet 238P Read (NIRCam Image).png
| caption = Comet 238P/Read by the James Webb Space Telescope on September 8, 2022
| discovery_ref =
| discoverer = Michael T. Read
{{small|(Spacewatch)}}
| discovered = 24 October 2005
| mp_category = Main-belt comet
Encke-type comet
| epoch = 7 January 2006
| uncertainty = 1
| aphelion = 3.9645 AU (Q)
| perihelion = 2.3647 AU (q)
| time_periastron = 2028-Jan-24{{cite web
|title=Horizons Batch for 238P/Read on 2028-Jan-24
|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=%27238P%27&START_TIME=%272028-Jan-24%27&STOP_TIME=%272028-Jan-25%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27
|accessdate=2023-04-30}} (JPL#37/Soln.date: 2023-Jan-03)
2022-Jun-05 (previous)
| semimajor = 3.1646 AU (a)
| eccentricity = 0.25277
| period = 5.63 yr
| avg_speed =
| inclination = 1.2662°
| asc_node = 51.647°
| mean_anomaly = 28.566° (M)
| arg_peri = 325.76°
| satellites =
| tisserand = 3.153
| mean_diameter = 0.6 km {{small|(approx.)}}
| mass =
| density = {{val|1.0|u=g/cm3}} {{small|(assumed)}}
| sidereal_day =
| albedo = 0.04 {{small|(assumed)}}
| spectral_type =
| temp_name1 = Kelvin
| min_temp_1 = 142 K
| mean_temp_1 = 159 K
| max_temp_1 = 184 K
| magnitude = 19.62 to 23.41
| abs_magnitude = {{val|20.1|0.4}}R
}}
238P/Read (P/2005 U1) is a main-belt comet discovered on 24 October 2005 by astronomer Michael T. Read using the Spacewatch 36-inch telescope on Kitt Peak National Observatory. It has an orbit within the asteroid belt and has displayed the coma of a traditional comet. It fits the definition of an Encke-type comet with (TJupiter > 3; a < aJupiter).
Description
Before it was discovered {{mp|238P}} came to perihelion on 2005 July 27. When it was discovered on 2005 October 24, it showed vigorous cometary activity until 2005 December 27. Outgassing likely began at least 2 months before discovery. The activity of {{mp|238P}} is much stronger than 133P/Elst-Pizarro and 176P/LINEAR. This may indicate that the impact assumed to have triggered {{mp|238P}}'s activity occurred very recently.
Observations of {{mp|238P}} when it was inactive in 2007 suggests that it has a small nucleus only about 0.6 km in diameter.
It came to perihelion on 2011 March 10, 2016 October 22. and 2022 June 5. It will next come to perihelion on 2028 January 24.
{{mp|238P/Read}} was the target of a mission proposal in NASA's Discovery Program in the 2010s called Proteus, however it was not selected for further development. Discovery program's founding mission was to an asteroid, but it went to a Near-Earth asteroid. A mission to a main-belt asteroid was proposed in the 1990s (also see Deep Impact (spacecraft)).
The comet was observed by James Webb Space Telescope during the 2022 perihelion and it was found spectrographicaly that its coma was composed by water vapor, due to water sublimation, and lacked significant {{CO2}} coma.{{cite journal |last1=Kelley |first1=Michael S. P. |last2=Hsieh |first2=Henry H. |last3=Bodewits |first3=Dennis |last4=Saki |first4=Mohammad |last5=Villanueva |first5=Geronimo L. |last6=Milam |first6=Stefanie N. |last7=Hammel |first7=Heidi B. |title=Spectroscopic identification of water emission from a main-belt comet |journal=Nature |date=15 May 2023 |pages=1–2 |doi=10.1038/s41586-023-06152-y|pmc=10371862 }}
See also
References
{{Reflist|refs=
|type = last observation: 2011-09-14
|title = JPL Small-Body Database Browser: 238P/Read (2005 U1)
|url = http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=P/2005+U1
|archive-url = https://web.archive.org/web/20200726071136/https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=P/2005+U1
|archive-date = 2020-07-26
|url-status = live
|access-date = 2012-08-08
}}
|title=238P/Read Orbit
|url=http://www.minorplanetcenter.net/db_search/show_object?object_id=238P
|publisher=Minor Planet Center
|access-date=2014-06-20}}
|date=May 2010
|title=Main Belt Comets
|publisher=Hawaii
|author=Henry H. Hsieh
|url=http://www.ifa.hawaii.edu/~hsieh/mbcs.shtml
|archive-url=https://web.archive.org/web/20110806021852/http://www.ifa.hawaii.edu/~hsieh/mbcs.shtml
|url-status=dead
|archive-date=2011-08-06
|access-date=2010-12-15
}} [http://star.pst.qub.ac.uk/~hhh/mbcs.shtml (older 2010 site)] {{webarchive|url=https://web.archive.org/web/20090810052739/http://star.pst.qub.ac.uk/~hhh/mbcs.shtml |date=August 10, 2009 }}
|title=Main Belt Comets
|publisher=UCLA, Department of Earth and Space Sciences
|author=David Jewitt
|author-link=David C. Jewitt
|url=http://www2.ess.ucla.edu/~jewitt/mbc.html
|access-date=2010-12-15}}
|date=2010-08-20
|title=P/Read (2005 U1 = 2010 N2)
|publisher=OAA Computing and Minor Planet Sections
|author=Syuichi Nakano
|author-link=Syuichi Nakano
|url=http://www.oaa.gr.jp/~oaacs/nk/nk1964.htm
|access-date=2011-07-25}}
|last=Hsieh |first=Henry H.
|author2=Jewitt
|author2-link=David C. Jewitt
|author3=David C.
|author4=Ishiguro, Masateru
|title=Physical Properties of Main-Belt Comet P/2005 U1 (Read)
|journal=The Astronomical Journal
|volume=137 |issue=1 |pages=157–168 |date=2009
|doi=10.1088/0004-6256/137/1/157
|arxiv=0810.1351
|bibcode=2009AJ....137..157H}}
}}
External links
- [http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=238P;orb=1 Orbital simulation] from JPL (Java) / [http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=238P Horizons Ephemeris]
- [https://archive.today/20121210105549/http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=c&o=0238P Elements and Ephemeris for 238P/Read] – Minor Planet Center
- [http://www.minorplanetcenter.net/db_search/show_object?object_id=238P&commit=Show 238P/Read] at the Minor Planet Center's Database
- [https://arxiv.org/abs/1106.0045 Main-Belt Comet 238P/Read Revisited] (arXiv:1106.0045 : 31 May 2011)
{{PeriodicComets Navigator|237P/LINEAR|239P/LINEAR}}
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{{Authority control}}
{{DEFAULTSORT:Read, 238P}}