The Chronicles of Local Space

A fictional exploration of nearby star systems

61 Ursae Majoris

Garumna Sequana Samara Tiberis Padus Danuvius
A photomontage of the six planets in the 61 Ursae Majoris system. The scale is one pixel per 300 kilometres.
The six planets in the 61 Ursae Majoris system.
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The 61 Ursae Majoris System
Right Ascension 11h 41m
Declination +34° 12'
Distance 30.91 ± 0.20 ly
Spectral Class G8V
Estimated Mass 0.81 × Sol
Luminosity 0.57 × Sol

Star charts
61 Ursae Majoris
as seen from Sol.
Sol as seen from
61 Ursae Majoris.
61 Ursae Majoris as seen from Sol Sol as seen from 61 Ursae Majoris
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Brightest stars as seen from 61 Ursae Majoris
Includes all stars of magnitude 1.00 and brighter
Star Magnitude Distance
Arcturus −1.12 22.4
Canopus −0.53 321.6
Beta Leonis (Denebola) −0.18 12.3
Xi Ursae Majoris (Alula Australis) 0.07 4.9
Alpha Aurigae (Capella) 0.12 43.5
Rigel 0.20 868.9
Betelgeuse 0.44 495.1
Regulus 0.56 54.7
Beta Centauri (Hadar) 0.64 398.1
Pollux 0.73 27.7
Alpha Crucis (Acrux) 0.81 327.7
Spica 0.82 231.6
Vega 0.82 36.1
Achernar 0.85 167.3
Epsilon Ursae Majoris (Alioth) 0.91 55.8

61 Ursae Majoris is a sunlike star with a spectral type of G8V that is located 30.9 light years from Sol. This star is slightly less massive than Sol, and has a luminosity slightly greater than half that of the Sun.

Local Space

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Stargates in this system
Destination Distance
Chara 7.5
Groombridge 1618 17.8

Probes from the Dandelion Project explored the system for the first time in 3006. The system has six planets, some of which have markedly eccentric orbits.


61 Ursae Majoris

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The planets of the 61 Ursae Majoris system
Planet SMA
(AU)
Orbital
Period
e Equatorial
Diameter
(km)
Mass
(Earths)
Density
(g/cm3)
Gravity
(Earth g)
Atmospheric
Pressure
(Earth=1)
Sidereal
Day
Mean
Solar
Day
Axial
Tilt
Known
Moons
Garumna 0.1285 18.699 d 0.0027 3623 0.01773 4.25 0.2197 &mdash 18d 16h 46.8m Synchronous 00° 17.0' 0
Sequana 0.2526 51.515 d 0.0845 5237 0.05648 4.49 0.3349 &mdash 51d 12h 21.8m Synchronous 00° 29.7' 0
Samara 0.8649 309.07 d 0.1840 11330 0.6640 5.23 0.8414 0.895 1d 04h 18.1m 1d 04h 24.6m 02° 56.6' 2
Tiberis 2.315 3.9145 y 0.0859 7542 0.1588 4.22 0.4540 &mdash 17h 56.3m 17h 56.9m 11° 56.7' 1
Padus 7.129 21.150 y 0.0744 58570 30.66 1.78 1.453 &mdash 14h 45.9m 14h 46.0m 16° 18.3' 6
Danuvius 30.88 190.70 y 0.4830 138900 233.5 1.07 1.968 &mdash 13h 20.7m 13h 20.7m 16° 18.3' 10
[ Skip Table ]
Natural satellites of the 61 Ursae Majoris system
Name Diameter
(km)
Period
(days)
Semimajor
Axis (km)
Ecc Inc
Natural Satellites of Samara
Selle 418 5.115 109400 0.0124 0.37
Avre 95 21.08 281200 0.0937 3.24
Natural Satellites of Tiberis
Anio 26 1.025 23260 0.2035 0.00
Natural Satellites of Padus
Secia 124 0.6299 52180 0.0009 0.02
Trebia 154 1.847 104800 0.0185 0.25
Ticinus 1702 2.463 127000 0.0108 0.27
Orgus 132 3.286 153900 0.0260 0.45
Tanarus 662 4.928 201600 0.0387 1.44
Addua 1830 14.67 417200 0.0023 0.17
Natural Satellites of Danuvius
Regen 86 0.7413 213100 0.0007 0.05
Arabo 1403 1.117 280100 0.0028 0.35
Oenus 2169 1.677 367200 0.0020 0.32
Ilz 83 1.677 367200 0.0020 0.23
Anisus 1707 2.789 515400 0.0045 0.48
Isarus 222 6.502 906200 0.1039 1.30
Tisia 6566 9.753 1188000 0.0018 0.25
Ilargus 158 14.63 1556000 0.1186 1.56
Moravia 1292 24.43 2190000 0.0701 0.80
Licca 572 52.61 3652000 0.0886 4.51

Garumna

Derivation of name: Latin name for the Garonne River in France and Spain, ultimately derived from the Gascon word for “river”.

Garumna is a heavily cratered planet slightly smaller than Mercury. The world lacks an appreciable atmosphere and is geologically inert.

Sequana

Derivation of name: Latin name for the Seine River in France, which is the river that flows through Paris.

Sequana is a small planet roughly the size of Mercury. Like Garumna, it is heavily cratered and lacks an appreciable atmosphere.

Samara

Samara is an ice-bound world with an eccentric orbit that is suitable for terraforming.
Samara
Derivation of name: Latin name for the Somme River in France, which in turn is derived from a Celtic word meaning “tranquillity”.

Samara is an ice-covered Earth-sized world with an eccentric orbit and a low axial tilt. The high eccentricity and low axial tilt combine to make the world the only potentially habitable world within ten parsecs of Sol where the primary driving force behind the seasons is the eccentricity of the orbit instead of the tilt of the axis.

The axial tilt of Samara is low enough that the larger moon of Selle transits the local sun on every orbit. Consequently, the day length on Samara varies little over the course of a year, even at high latitudes.

The eccentricity of the orbit causes the time of sunrise on Samara to vary by about of a day. The latest sunrises and sunsets occur when Samara is halfway between periastron and apastron, the equivalent of the end of the global summer.

Tiberis

Derivation of name: Latin name for the Tiber River in Italy, which is the river that flows through Rome.

Tiberus is a world slightly larger than Mars with a similar climate.

Padus

Derivation of name: Latin name for the Po River in northern Italy.

Padus is a blue gas giant with a mass about twice that of Neptune.

Danuvius

Danuvius is the largest planet in the 61 Ursae Majoris system.
Danuvius
Derivation of name: Latin name for the Danube River in Europe, from an Iranian word *danu meaning “river” or “stream”.

Danuvius is the largest planet in the 61 Ursae Majoris system with a mass slightly less than three-quarters of that of Jupiter. It is a bluish world, with its cloud features mainly shaped by internal heat.

Its orbit is unusual for such a large planet, being markedly eccentric with an eccentricity of about 0.5. The high eccentricity causes the planet to vary considerably in brightness as seen from Samara over the course of its orbit. When at periastron, it is a moderately bright planet at opposition as seen from Samara with a magnitude of about 2.5, but near apastron it fades to the invisibility of magnitude 7.


Further reading

Fictional depictions of the 61 Ursae Majoris system

Imagination is vaster than all of space.

Nonfictional links

Just the facts.

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