50 Fun Facts About Haumea

Where in the Solar System is the dwarf planet Haumea?

It is the third-largest known trans-Neptunian object after Eris and Pluto, about the size of Uranus's moon Titania.

Haumea is named after a goddess from the mythology of which Pacific islands?

The Caltech team chose the names to honour Mauna Kea, where the moons were found.

The goddess Haumea presides over what?

Her many children were said to spring from different parts of her body, an apt image for a body that shed a family of fragments.

What is Haumea's most unusual physical feature?

Its long axis is roughly twice its short one, thanks to a spin of under four hours.

How long does Haumea take to rotate once?

Faster than any other known body in equilibrium; a little quicker and it would split into a dumbbell.

If Haumea rotated much faster than it does, what is the predicted result?

The current spin is thought to be a leftover of the giant impact that made its moons and family.

What was discovered around Haumea in 2017, a first for any object beyond Neptune?

It showed up in a stellar occultation on 21 January 2017 and was reported in Nature that October.

Roughly what is the radius of Haumea's ring?

It is about 70 km wide and sits well within Haumea's Roche limit.

How many moons does Haumea have?

Both were found in 2005 with the Keck telescopes and are named after daughters of the goddess.

What are Haumea's two moons called?

Both are daughters of the goddess Haumea; the Caltech team first nicknamed them Rudolph and Blitzen.

What festive nicknames did the discovery team first give Haumea and its two moons?

Haumea was found on 28 December 2004, just after Christmas.

Which moon of Haumea, the larger and outer one, was nicknamed 'Rudolph'?

About 310 km across, it circles Haumea every 49 days and is coated in crystalline water ice.

Which team leader from Caltech discovered Haumea in December 2004?

The same team found Eris and Makemake, and Brown wrote 'How I Killed Pluto and Why It Had It Coming'.

Which Spanish astronomer's team announced Haumea first, in July 2005, using 2003 images?

Brown then discovered the Spanish observatory had accessed his online logs the day before, and cried foul.

What did the Caltech team leader accuse the Spanish team of doing before their announcement?

Ortiz admitted looking at the logs but denied wrongdoing, saying he was checking whether Caltech had a new object.

What provisional designation did Haumea carry before it was named?

The '2003' reflects the date of the Spanish team's discovery image, not Caltech's 2004 one.

What name did the Spanish team propose for the dwarf planet, which the IAU rejected in 2008?

An Iberian underworld goddess; underworld names are reserved for plutinos, and Haumea is not one.

How did the IAU rule on who discovered Haumea?

The naming choice was seen as siding with the Caltech team without formally awarding discovery.

Haumea's surface is covered mostly in what?

Odd, because crystalline ice should not form or survive at 50 K under cosmic-ray bombardment.

Haumea's albedo of 0.6 to 0.8 makes it about as reflective as what?

Best-fit models make 66% to 80% of the surface pure crystalline water ice.

What large feature was spotted on Haumea's bright white surface in 2009?

Possibly an impact scar rich in minerals and organic compounds.

Haumea's mass is roughly what fraction of Pluto's?

That is 1/1400 of Earth's; nearly all the system's mass is in Haumea itself.

According to a 2019 model, Haumea's dimensions are roughly what?

Its long axis is about the diameter of Pluto; its poles are only about half that apart.

How long does Haumea take to orbit the Sun?

It passed aphelion in 1992 and will reach perihelion in 2133.

Haumea is thought to be in an intermittent orbital resonance with Neptune of what ratio?

The resonance switches on and off twice every 4.6-million-year precession cycle.

Haumea's high albedo, fast spin, rings and moons are all thought to result from what?

The impact stripped much of its ice mantle and scattered a family of icy fragments.

Haumea is the largest member of what, the first of its kind identified beyond Neptune?

Members such as 2002 TX300 share its orbit and icy surface, all fragments of one shattered ancestor.

Which spacecraft observed Haumea from afar in 2007, 2017 and 2020?

Its outbound path let it view Haumea at phase angles impossible from Earth.

How bright is Haumea as seen from Earth?

Only Pluto and Makemake outshine it in the Kuiper belt; a large amateur telescope can pick it up.

Precovery images of Haumea have been identified as far back as which year?

Nobody noticed it in the old plates until they knew where to look.

How was Haumea's mass calculated?

The answer is 28% of the Pluto system's mass and 6% of the Moon's.

Why did the Caltech team choose Pacific-island names for Haumea and its companions?

Gemini and Keck stand on Mauna Kea, and Haumea is the island's matron goddess.

Who on the Caltech team proposed the names?

Haumea's many body-born children matched the swarm of fragments knocked off in the ancient collision.

In island myth, how were most of the goddess Haumea's children born?

Only Pele, the volcano goddess, was born the normal way.

Which famous volcano goddess is a daughter of Haumea in the myths?

Hiʻiaka and Nāmaka, after whom the moons are named, are her sisters.

Hiʻiaka, the goddess after whom Haumea's larger moon is named, is the patron goddess of what?

She is also patron goddess of the Big Island of Hawaii.

Namaka, the smaller moon, is named after a spirit of what?

It orbits every 18 days on a wild, tilted path that its bigger sibling keeps disturbing.

How long does the inner moon Namaka take to orbit Haumea?

It has a tenth the mass of Hiʻiaka and an eccentric orbit inclined 13° to it.

Which absence in Haumea's spectrum points to a warm collisional past, in contrast to Makemake?

A hot impact would have driven off the volatile ices.

Haumea's orbit is inclined to the ecliptic by roughly how much?

Its perihelion is 35 AU and it is currently more than 50 AU from the Sun.

What is Haumea's minor-planet number?

Pluto is 134340 and Eris 136199; Ceres is number 1.

How is the 2019 model's core of Haumea described?

An icy mantle 70 to 170 km thick wraps a rocky core of about 1,626 × 1,446 × 940 km.

Haumea's ring lies close to which resonance with the dwarf planet's spin?

A 2019 study found the exact 1:3 resonance unstable but a stable zone nearby.

Between about 2008 and 2011, what could observers on Earth watch the moon Namaka do?

The moons' orbits were nearly edge-on, offering rare transits.

On which observatory's frames, exposed that May, did Caltech spot Haumea in December 2004?

The team spotted it on 28 December 2004 in frames exposed the previous May.

On what date was the dwarf planet officially given the name Haumea?

The IAU used the Caltech team's name even though it did not rule on who had discovered the object.

Haumea's perihelion, the closest it comes to the Sun, is roughly how far out?

It passed aphelion in early 1992 and will not reach perihelion again until 2133.

In which year will Haumea next reach perihelion?

It is currently more than 50 AU from the Sun on a 284-285-year orbit.

Who designed the planetary symbol for Haumea that appears in Unicode, combining Hawaiian petroglyphs?

The Massachusetts software engineer's design merges petroglyphs meaning 'woman' and 'childbirth'; it is used mostly by astrologers but also by NASA.

Both of Haumea's moons were discovered in 2005 using which Hawaiian telescopes?

The larger, outer moon was found on 26 January and the smaller, inner one on 30 June that year.