2011 MM4

{{Short description|Centaur}} {{Use dmy dates|date=August 2021}} {{DISPLAYTITLE:{{mp|2011 MM|4}}}} {{Infobox planet | minorplanet = yes | name = {{mp| 2011 MM|4}} | background = #C7FF8F | image = | image_size = | caption = | discovery_ref = <ref name="MPC-object" /> | discoverer = Pan-STARRS 1 | discovery_site = Haleakala Obs. | discovered = 24 June 2011 | mpc_name = {{mp|2011 MM|4}} | alt_names = | pronounced = | named_after = | mp_category = {{nowrap|centaur<ref name="jpldata" /><ref name="johnstonsarchive-TNO-list" /><ref name="MPC-CEN-SDO-list" />{{·}}damocloid}}<br />distant<ref name="MPC-object" /> | orbit_ref = <ref name="jpldata" /> | epoch = 23 March 2018 (JD 2458200.5) | uncertainty = 0 | observation_arc = 6.99 yr (2,552 d) | aphelion = 31.121 AU | perihelion = 11.138 AU | semimajor = 21.129 AU | eccentricity = 0.4729 | period = 97.12 yr (35,473 d) | mean_anomaly = 49.176° | mean_motion = {{Deg2DMS|0.0101|sup=ms}} / day | inclination = 100.48° | asc_node = 282.45° | arg_peri = 6.86° | tisserand = −0.4 | mean_diameter = {{val|64|ul=km}}<ref name="johnstonsarchive-TNO-list" /><ref name="Bauer-2013" /> | rotation = | albedo = 0.083<ref name="johnstonsarchive-TNO-list" /><ref name="Bauer-2013" /> | spectral_type = | abs_magnitude = 9.5<ref name="MPC-object" /><ref name="jpldata" /> }} '''{{mp|2011 MM|4}}''' is a sizable centaur and retrograde damocloid from the outer Solar System, approximately {{convert|64|km|mi|abbr=off|sigfig=2|sp=us}} in diameter. It was discovered on 24 June 2011, by astronomers with the Pan-STARRS 1 at the Haleakala Obs. in Hawaii.<ref name="MPC-object" /><ref name="johnstonsarchive-TNO-list" />

== Orbit and classification ==

{{mp|2011 MM|4}} orbits the Sun at a distance of 11.1–31.2 AU once every 97 years and 2 months (35,473 days; semi-major axis of 21.13 AU). Its orbit has an eccentricity of 0.47 and an inclination of 100° with respect to the ecliptic.<ref name="jpldata" /> The body's observation arc begins at Pan-STARRS in June 2010.<ref name="MPC-object" />

=== Retrograde centaur and damocloid ===

{{mp|2011 MM|4}} is a member of the centaurs, a population of inward-moving bodies transiting from the Kuiper belt to the group of Jupiter-family comets. Orbiting mainly between Jupiter and Neptune, they typically have a semi-major axis of 5.5 to 30.1 AU. Centaurs are cometary-like bodies with an eccentric orbit. Their short dynamical lifetime is due to the perturbing forces exerted on them by the outer planets of the Solar System.<ref name="Peixinho-2003" />

The object is on a retrograde orbit as it has an inclination of more than 90°.<ref name="jpldata" /><ref name="Fuente-Marcos-2014" /> There are only about a hundred known retrograde minor planets out of nearly 800,000 observed bodies, and, together with {{mpl-|468861|2013 LU|28}} and {{mpl-|342842|2008 YB|3}}, it is among the largest such objects.<ref name="Fuente-Marcos-2014" /> The object also meets the orbital definition for being a damocloid. This is a small group of cometary-like objects without a coma or tail and a Tisserand's parameter with respect to Jupiter of less than 2 besides a retrograde orbit.

== Numbering and naming ==

{{As of|2025}}, {{mp|2011 MM|4}} has not been numbered or named by the Minor Planet Center.

== Physical characteristics ==

=== Diameter and albedo ===

According to the survey of centaurs and scattered-disk objects carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, {{mp|2011 MM|4}} measures 64 kilometers in diameter and its surface has an albedo of 0.083,<ref name="Bauer-2013" /> which makes it too small to be considered as a dwarf-planet candidate.

=== Rotation period ===

{{As of|2021}}, no rotational lightcurve of has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.<ref name="jpldata" /><ref name="lcdb" />

== See also == * {{Section link|List of centaurs (small Solar System bodies)|2011 MM4}}

== References == {{reflist|30em|refs=

<ref name="jpldata">{{cite web |type = 2017-10-29 last obs. |title = JPL Small-Body Database Browser: 2011 MM4 |url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2011%20MM4 |publisher = Jet Propulsion Laboratory |accessdate = 18 October 2018}}</ref>

<ref name="MPC-object">{{cite web |title = 2011 MM4 |work = Minor Planet Center |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=2011+mm4 |accessdate = 18 October 2018}}</ref>

<ref name="johnstonsarchive-TNO-list">{{cite web |title = List of Known Trans-Neptunian Objects |work = Johnston's Archive |date = 7 October 2018 |last = Johnston |first= Wm. Robert |url = http://www.johnstonsarchive.net/astro/tnoslist.html |accessdate = 17 October 2018}}</ref>

<ref name="MPC-CEN-SDO-list">{{cite web |title = List Of Centaurs and Scattered-Disk Objects |work = Minor Planet Center |url = https://www.minorplanetcenter.net/iau/lists/t_centaurs.html |accessdate = 18 October 2018}}</ref>

<ref name="Fuente-Marcos-2014">{{Cite journal |first1 = C. |last1 = de la Fuente Marcos |first2 = R. |last2 = de la Fuente Marcos |date = August 2014 |title = Large retrograde Centaurs: visitors from the Oort cloud? |journal = Astrophysics and Space Science |volume = 352 |issue = 2 |pages = 409–419(Ap&SSHomepage) |bibcode = 2014Ap&SS.352..409D |doi = 10.1007/s10509-014-1993-9 |arxiv = 1406.1450 |s2cid = 189843380 }}</ref>

<ref name="Bauer-2013">{{Cite journal |display-authors = 6 |first1 = James M. |last1 = Bauer |first2 = Tommy |last2 = Grav |first3 = Erin |last3 = Blauvelt |first4 = A. K. |last4 = Mainzer |first5 = Joseph R. |last5 = Masiero |first6 = Rachel |last6 = Stevenson |first7 = Emily |last7 = Kramer |first8 = Yan R. |last8 = Fernández |first9 = C. M. |last9 = Lisse |first10 = Roc M. |last10 = Cutri |first11 = Paul R. |last11 = Weissman |first12 = John W. |last12 = Dailey |first13 = Frank J. |last13 = Masci |first14 = Russel |last14 = Walker |first15 = Adam |last15 = Waszczak |first16 = Carrie R. |last16 = Nugent |first17 = Karen J. |last17 = Meech |first18 = Andrew |last18 = Lucas |first19 = George |last19 = Pearman |first20 = Ashlee |last20 = Wilkins |first21 = Jessica |last21 = Watkins |first22 = Shrinivas |last22 = Kulkarni |first23 = Edward L. |last23 = Wright |last24 = WISE Team |last25 = PTF Team |date = August 2013 |title = Centaurs and Scattered Disk Objects in the Thermal Infrared: Analysis of WISE/NEOWISE Observations |journal = The Astrophysical Journal |volume = 773 |issue = 1 |page = 11 |bibcode = 2013ApJ...773...22B |doi = 10.1088/0004-637X/773/1/22 |arxiv = 1306.1862 |s2cid = 51139703 }}</ref>

<ref name="Peixinho-2003">{{Cite journal |first1 = N. |last1 = Peixinho |first2 = A. |last2 = Doressoundiram |first3 = A. |last3 = Delsanti |first4 = H. |last4 = Boehnhardt |first5 = M. A. |last5 = Barucci |first6 = I. |last6 = Belskaya |date = October 2003 |title = Reopening the TNOs color controversy: Centaurs bimodality and TNOs unimodality |journal = Astronomy and Astrophysics |volume = 410 |issue = 3 |pages = L29–L32 |bibcode = 2003A&A...410L..29P |doi = 10.1051/0004-6361:20031420 |arxiv = astro-ph/0309428 |s2cid = 8515984 }}</ref>

<ref name="lcdb">{{cite LCDB|number = 342842 |accessdate = 18 October 2018}}</ref>

}}

== External links == * [https://www.minorplanetcenter.net/iau/lists/t_centaurs.html List Of Centaurs and Scattered-Disk Objects], ''Minor Planet Center'' * {{AstDys|2011+MM4}} * {{JPL small body|id=2011+MM4}}

{{Small Solar System bodies}}

{{DEFAULTSORT:2011 MM4}} # 2011 MM4 Category:Minor planet object articles (unnumbered) # 20110624 Category:Minor planets with a retrograde orbit