The Orion's Arm Universe Project Forums

Exoplanet Discoveries and Updates
(04-29-2020, 08:37 PM)QuantumJack1 Wrote: I have examined all pages under topic Inner Sphere and found 5 problematic systems requiring edition.

1. Pi Mensae (Alauda):
1 new planet without change existing.
b: 4.82 mearth, 2.042 rearth, 0.06839 AU, SubNeptunian Sulfidian;

2. Gliese 676 (HIP 85647, Dante):
A totally different system is found with 4 planets.
d: >4.4 mearth, 0.0413 AU, SuperTerrestrial Chloridian Hephaestian;
e: >11.5 mearth, 0.187 AU, MesoNeptunian Acidian;
b: >6.7 mjupiter, 1.80 AU, SuperJovian Ammonian;
c: ~6.8 mjupiter, 5.2 AU, SuperJovian Cryoazurian;
The two hypothetical planets are impossible to remain unchanged. My suggestion is move Dante outer to ~0.25 AU to avoid planet e, and since no giant planet is likely to exist and avoid detection between b and c, the name Beatrice (3.2 AU) could be regiven to b or c.

3. Hamal (Alpha Arietis, Gatewai):
1 new planet without change existing.
b: >1.8 mjupiter, 1.2 AU, MesoJovian Chloridian;

4. Gliese 581:
Planet d is confirmed but missing, and colors of some planets need edition.
e (Gules): Very high pos., >1.7 mearth, 0.02815 AU, MesoTerrestrial Mesoazurian Cytherian;
b (Vert): Very high pos., >15.8 mearth, 0.04061 AU, MesoNeptunian Mesoazurian;
c (Argent): Very high pos., >5.5 mearth, 0.0721 AU, SubNeptunian Acidian;
g (Zarmina): Medium pos., >2.2 mearth, 0.146 AU, MesoTerrestrial Aquean Gaian;
d: High pos., 6.98 mearth, 0.21847 AU, SubNeptunian Aquean;
f: Low pos., >7.0 mearth, 0.758 AU, SubNeptunian Ammonian;
h (Azure): Low pos., ~20.4 mearth, 22.109 AU, MesoNeptunian Neonian;

5. Nu2 Lupi (Newroot):
3 planets are found in close orbit.
b: >5.28 mearth, 0.0933 AU, SuperTerrestrial Sulfidian Hephaestian;
c: >11.38 mearth, 0.1665 AU, MesoNeptunian Chloridian;
d: >9.59 mearth, 0.411 AU, SubNeptunian Acidian;
Most of existing article can remain. The number of inner planets mined to construct The System Grid will increase from 2 to 3, or one planet can remain for other use. Although these planets are totally destructed, they are still notable in EG.

Pi Mensae: No problem here, just add planet c. I think we should give the star and its planets some names. Any idea?

Gliese 676: I already have some plans for Gliese 676 system. Following the naming convention, the star and the planets can be named Alighieri (star A), Lucifer (Ad), Saint Lucy (Ae), (Dante is located here), Beatrice (Ab), and Virgil (Ac). The companion star could be Boccaccio.

Alpha Arietis (Hamal): I think we should do away with the terraformed planet, and the name Gatewai can be applied to the gas giant.

Gliese 581: Link to debate.

Nu2 Lupi: We can certainly add mentions of them, but they have already been disassembled.
8 planetary systems within 15 ly are still blank in EG. These system can be offered to various creative editors for next step worldbuilding.


Groombridge 34
Ab: 3.03m, 0.072au, T+ Acidian Cytherian;
Ac: 36m, 5.4au, N0 Cryoazurian;

Gliese 1061
b: 1.38m, 0.021au, T0 Acidian Cytherian;
c: 1.75m, 0.035au, T0 Aquean Gaian;
d: 1.68m, 0.054au, T0 Aquean Europan;

YZ Ceti
e: 0.472m, 0.01018au, T0 Mesoazurian Hermian;
b: 0.75m, 0.01557au, T0 Mesoazurian Agonian;
c: 0.98m, 0.02090au, T0 Acidian Cytherian;
d: 1.14m, 0.02764au, T0 Acidian Cytherian;

Teegarden's star
b: 1.05m, 0.0252au, T0 Aquean Gaian;
c: 1.11m, 0.0443au, T0 Aquean Europan;

Wolf 1061
b: 1.91m, 0.0375au, T0 Mesoazurian Cytherian;
c: 3.41m, 0.0890au, T+ Aquean Gaian;
d: 7.7m, 0.470au, N- Ammonian;

L 1159-16
b: 4.0m, 0.016au, T+ Acidian Cytherian;
c: 26.0m, 0.406au, N0 Methanean;
d: 81.5m, 0.881au, J- Cryoazurian;

Gliese 674
b: 11.8m, 0.039au, N0 Mesoazurian;

Gliese 687
b: 18.394m, 0.16353au, N0 Aquean;
At least some of these may be on the Master Star List - Groombridge 34 is, I don't have time to check the others. If they are not, they can be added.

(04-30-2020, 11:02 PM)Drashner1 Wrote: At least some of these may be on the Master Star List - Groombridge 34 is, I don't have time to check the others. If they are not, they can be added.


The Groombridge 34 system is being worked on right now, by the way. Feel free to write up one of the other systems.
Dagon seems to have evaporated, despite having received an IAU name relatively recently. It was probably a debris cloud caused by a collision. I wouldn't rule out an eventual coalescence, however.
A few days ago, I found a paper measuring 82 Eridani's debris disk's inclination, yielding a result of 50 degrees. Assuming that the planets are aligned with this disk, which is likely, this would mean the known planets in this system would actually be roughly 31% more massive than their minimum mass.

Here are the 82 Eridani's planets' true mass (in Earth masses) based on the inclination of the debris disk (also with correct designations, in order of distance from primary):

f: 1.34 (likely rocky)
b: 3.68 (likely volatile-rich)
g: 3.29 (likely volatile-rich)
c: 4.60 (likely volatile-rich)
d: 6.23 (likely gas-rich)
e: 13.39 (Neptunian)

Terranova should still be a Mars-size world.

The paper also looks at HD 38858, 50 light-years away from Sol, whose sole known planet's minimum mass is twice Neptune's mass and orbit in a moderately eccentric path at roughly 1 AU.
New, low-noise RV measurements of Proxima, home to two known planets, has been obtained from the ESPRESSO spectrograph, confirming the presence of Proxima b as well as detecting a second signal with a period of 5.15 days and semi-amplitude of 40 cm/s. If the signal is caused by a planet companion, the signal would correspond to a planet with a minimum mass of 0.29 Earths and a semi-major axis of 0.029 AU.


Proxima's third planet candidate
Semi-major axis: 0.029 AU (calculated by myself, using 0.1221 solar masses for star mass)
Orbital period: 5.15 days
Minimum mass: 0.29 Earth masses
Mass (assuming the same inclination as Proxima c's): 0.62 Earth masses

The paper also revised Proxima b's mass, yielding a minimum mass of 1.173 Earth masses. Including inclination (again, assuming the same inclination as c), Proxima b's likely true mass is roughly 2.5 Earth masses.
Yet another super-Earth has been found in a tight orbit around the red dwarf star CD Ceti / GJ 1057, 28 light-years away from Sol.


CD Ceti b
Semi-major axis: 0.0185 AU
Orbital period: 2.29070 days
Minimum mass: 3.95 Earth masses
(04-21-2020, 10:59 AM)The Astronomer Wrote: The HST was finally pointed back to Fomalhaut, again confirming that Fomalhaut b is, indeed, a dust cloud created by a collision between two large planetesimals, not a planet.

I don't know what IAU is going to do with the name Dagon. Let's just hope it gets re-applied to the first planet detected in this system.

I've simply removed all mention of Dagon from the Fomalhaut article; maybe we can put it back if the name is reused.
The young hot Neptune planet AU Microscopii b has been confirmed. There was news of the planet's detection floating around for a while so I'm not surprised to see it confirmed. They have also detected a single transit of what appears to be the second planet orbiting once every roughly 30 days. This candidate transit corresponds to a planet roughly three-fifth Neptune's radius.

AU Microscopii b
Semi-major axis: 0.066 AU
Eccentricity: 0.10
Orbital period: 8.46321 days
Mass: <3.4 Neptunes
Radius: 1.08 Neptunes

Second AU Microscopii planet candidate
Semi-major axis: ~0.15 AU
Eccentricity: ~0.20
Orbital period: ~30 days
Radius: 0.60 Neptunes

Forum Jump:

Users browsing this thread: 8 Guest(s)