Science · Makemake

What the research says about Makemake

Makemake is too far away for any spacecraft to have visited, so almost everything we know comes from telescopes. These are ten research papers, all free to read on arXiv, that show how astronomers worked out its size, its spin, its moon and the strange chemistry on its surface.

Papers 10
Topics 4
Reviewed Oct 24, 2026
Source arXiv.org

Our own simplified drawing. No figures are taken from the papers.

Known so far

Every number links to the paper it comes from.

Diameter: 1,434km2Across the equator, from 2011 occultation timings (± 14 km).
Day length: 22.83hours3One full spin, from brightness data taken 2006 to 2017.
Moon's orbit: 18.0days5Preliminary, at about 22,250 km from Makemake.
Reflectivity: 0.81albedo2Share of visible sunlight its icy surface reflects.

Discovery, size & spin

3 papers

How Makemake was first examined after its 2005 discovery, how big it is and how long its day lasts.

[1]2005astro-phPeer-reviewed

Satellites of the largest Kuiper belt objects

M. E. Brown, M. A. van Dam, A. H. Bouchez & 12 others

What they foundNo moon brighter than 0.5% of Makemake showed up within 0.4 arcseconds of it, even though three of the four brightest Kuiper belt objects did have moons.

Why it mattersIt made Makemake the odd one out for a decade, until Hubble found a much fainter moon in 2015 (see the Moon section).

What they studied

The team searched the four brightest Kuiper belt objects with Keck Observatory's then-new laser guide star adaptive optics system.

arXiv:astro-ph/0510029Abstract (opens arXiv)PDF (opens arXiv)

[2]2013astro-ph.EPPeer-reviewed

On the size, shape, and density of dwarf planet Makemake

M. E. Brown

What they foundMakemake is close to round, about 1,434 km across at the equator and 1,422 km pole to pole, with a very bright surface (albedo about 0.81).

Why it mattersIt corrected an earlier claim: the occultation data cannot pin down Makemake's density, so size and shape are solid but its make-up is not.

What they studied

The author re-analysed the timings of a 2011 stellar occultation, when Makemake passed in front of a star, using a stricter statistical method.

Source for: Diameter · Reflectivity

arXiv:1304.1041Abstract (opens arXiv)PDF (opens arXiv)

[3]2019astro-ph.EPPreprint

Long-term photometric monitoring of the dwarf planet (136472) Makemake

T. A. Hromakina, I. N. Belskaya, Yu. N. Krugly & 17 others

What they foundMakemake spins once every 22.83 hours, slower than earlier studies said, and its brightness barely changes as it turns.

Why it mattersA tiny brightness wobble means Makemake is nearly round or seen almost pole-on, which matters whenever brightness is turned into size.

What they studied

The team tracked Makemake's brightness with several telescopes between 2006 and 2017.

Source for: Day length

arXiv:1904.03679Abstract (opens arXiv)PDF (opens arXiv)

Its moon, MK2

2 papers

A faint, dark moon found by Hubble in 2015, and the first attempt to pin down its orbit.

[4]2016astro-ph.EPPreprint

Discovery of a Makemakean Moon

Alex H. Parker, Marc W. Buie, Will M. Grundy & 1 other

What they foundMakemake has a moon, provisionally S/2015 (136472) 1 and nicknamed MK2, which is 7.80 magnitudes fainter than Makemake.

Why it mattersIts nearly edge-on orbit probably hid it in Makemake's glare for years, and its dark surface could explain dark material earlier heat measurements had blamed on Makemake itself.

What they studied

The discovery came from Hubble Space Telescope (WFC3) images taken in April 2015.

arXiv:1604.07461Abstract (opens arXiv)PDF (opens arXiv)

[5]2025astro-ph.EPPreprint

A preliminary orbit for the satellite of dwarf planet (136472) Makemake

Daniel Bamberger

What they foundThe moon's best-fit circular orbit takes about 18.02 days at roughly 22,250 km from Makemake, tilted nearly edge-on to our line of sight.

Why it mattersBecause that orbit is nearly edge-on, Makemake and its moon may already be, or soon start, passing in front of each other as seen from Earth.

What they studied

The author fitted the moon's positions in archival Hubble images taken between April 2015 and February 2019.

Source for: Moon's orbit

arXiv:2509.05880Abstract (opens arXiv)PDF (opens arXiv)

Surface, methane ice & activity

3 papers

JWST and ground telescopes see methane ice, other hydrocarbons, methane gas and unexpected warmth.

[6]2023astro-ph.EPPreprint

Measurement of D/H and 13C/12C Ratios in Methane Ice on Eris and Makemake: Evidence for Internal Activity

W. M. Grundy, I. Wong, C. R. Glein & 11 others

What they foundJWST picked out heavy, deuterium-bearing methane on Makemake for the first time, giving a deuterium-to-hydrogen ratio of about 2.9 × 10⁻⁴.

Why it mattersThat ratio is closer to water than to comet methane, hinting the methane was made inside Makemake, possibly by geological processes that may still be going on.

What they studied

The team measured the infrared light reflected by Eris and Makemake with JWST's NIRSpec spectrograph.

arXiv:2309.05085Abstract (opens arXiv)PDF (opens arXiv)

[7]2025astro-ph.EPPreprint

JWST Detection of Hydrocarbon Ices and Methane Gas on Makemake

Silvia Protopapa, Ian Wong, Emmanuel Lellouch & 15 others

What they foundMethane gas glows in sunlight above Makemake, making it only the second object beyond Neptune, after Pluto, with confirmed gas release.

Why it mattersWhether that gas is a thin atmosphere or a local plume is still open, but either way Makemake is less frozen and quiet than thought.

What they studied

New JWST spectra show a surface of methane ice mixed with ethane, acetylene and other products of sunlight breaking methane apart.

arXiv:2509.06772Abstract (opens arXiv)PDF (opens arXiv)

[8]2024astro-ph.EPPreprint

Prominent mid-infrared excess of the dwarf planet (136472) Makemake discovered by JWST/MIRI indicates ongoing activity

Csaba Kiss, Thomas G. Müller, Anikó Farkas-Takács & 18 others

What they foundMakemake gives off far more heat than expected at 18 to 25 microns, pointing to spots near 150 K, far warmer than sunlight alone can make out there.

Why it mattersIf it is an active warm region, possibly cryovolcanic, or an unseen ring of fine dust, either would be a first beyond Neptune.

What they studied

The team measured Makemake's heat glow with JWST's mid-infrared instrument, MIRI, and combined it with earlier Spitzer and Herschel measurements.

arXiv:2410.22544Abstract (opens arXiv)PDF (opens arXiv)

Origins & interior

2 papers

Where Makemake's methane came from, and what that says about how it formed.

[9]2023astro-ph.EPPreprint

Moderate D/H Ratios in Methane Ice on Eris and Makemake as Evidence of Hydrothermal or Metamorphic Processes in Their Interiors: Geochemical Analysis

Christopher R. Glein, William M. Grundy, Jonathan I. Lunine & 7 others

What they foundMethane left over from the Sun's birth cloud does not fit Makemake's chemistry, while methane made inside the body, from hot water reacting with rock or heated organic material, does.

Why it mattersThat would mean Makemake has a rocky core that once got hotter than about 150 °C and may still be warm.

What they studied

The study used geochemical models to test three sources of methane, primordial, made from CO₂ or CO, or made from organics, against the JWST deuterium ratios.

arXiv:2309.05549Abstract (opens arXiv)PDF (opens arXiv)

[10]2025astro-ph.EPPreprint

Primordial Origin of Methane on Eris and Makemake Supported by D/H Ratios

Olivier Mousis, Aaron Werlen, Tom Benest Couzinou & 1 other

What they foundWith a model of how deuterium is exchanged in the disk the planets formed from, the methane on Eris and Makemake can be primordial after all.

Why it mattersTogether with the paper above, it shows that the origin of Makemake's methane is an open, actively debated question.

What they studied

The authors ran a time-dependent model of the young solar nebula with deuterium chemistry, calibrated with the ratio measured in methane at comet 67P.

arXiv:2503.15652Abstract (opens arXiv)PDF (opens arXiv)

New research

New papers on Makemake, checked weekly, summarized after a person reads it.

RSS feed

No new papers on Makemake this week. We check arXiv every week.

How we choose papers

We search arXiv for Makemake papers and keep the ones that add something new, are clearly written up and are relevant to a general reader. A person reads every abstract.

Our own words, our own drawings

Summaries are written by us from each paper’s abstract, not copied. Diagrams are our own simplified drawings, not figures from the papers.

Preprint vs. peer-reviewed

“Peer-reviewed” means arXiv lists a journal reference for the paper. Everything else is marked “Preprint”: shared openly, possibly before or without journal review.

Paper metadata courtesy of arXiv. Summaries written by us; read the original papers via the links. Paper metadata from arXiv.org, which does not endorse this site.