Exoplanet Discoveries and Updates

[AstroChara]

18 Scorpii b would probably be cannibalised by the factions that constructed Felicidade. Either as mass to build the megastructure, or mass to create a wormhole.

This planet could be Bagulho (although the picture would have to be changed) or the other gas giant in the system. Any name idea?

[AstroChara]

The paper on the inclination of Proxima c's orbit is released. Assuming prograde orbit, they arrived at 152+-14 degrees. This means Proxima c is roughly 2 times more massive than its minimum mass of 5.8 Earth masses. It is reasonable to assume that Proxima b is in the same orbital plane, in which case the planet would be 2.7 times more massive than Earth. I'll put this in my next Proxima draft, whenever that comes. (Btw the Architect, if you want to take this Buddhist system up, you're free to, although the Buddhism in this case not being Theravada might not be in your field, so... idk :/)



Interestingly, the orbit of Proxima c obtained from this work seems to agree with the disproven debris disk reported back in 2017.

The inclination of the dust rings identified by Anglada et al. (2017) (≈ 45°) from ALMA observations of Proxima is compatible with our derived inclination. The position angle of the major axis of the ring (≈ 140°) is also in agreement with the position angle of the line of nodes of the orbit of Proxima c

[AstroChara]

On new exoplanet discoveries, we have GJ 338 Bb, a hot MesoNeptunian planet.

GJ 338 Bb
Semi-major axis: 0.141 AU
Eccentricity: 0.11
Orbital period: 24.45 days
Minimum mass: 10.27 / 9.97 Earth masses (two solutions due to the star having two possible mass values. The first was derived by adopting the mass of 0.64 ± 0.07 M_Sol for the parent star, while the second was derived with stellar mass determined by Schweitzer et al. (2019).)

[dangerous_safety]

Tracing through the references in the new Proxima c paper, I found what seems to be the the original paper for proxima c. Interestingly, it gives a lower mass sin i for proxima b, only 1.0 earths, which is used in the latest paper to estimate a proper mass of 2.1 earths.

If we assume the coplanarity of the orbits of the planets Proxima b and c, the de-projected mass of the close-in planet is mb = 2.1 +1.9 −0.6 M⊕ (adopting mb sin i = 1.0±0.1 M⊕ from Damasso et al. 2020).

[AstroChara]

Tracing through the references in the new Proxima c paper, I found what seems to be the the original paper for proxima c. Interestingly, it gives a lower mass sin i for proxima b, only 1.0 earths, which is used in the latest paper to estimate a proper mass of 2.1 earths.

If we assume the coplanarity of the orbits of the planets Proxima b and c, the de-projected mass of the close-in planet is mb = 2.1 +1.9 −0.6 M⊕ (adopting mb sin i = 1.0±0.1 M⊕ from Damasso et al. 2020).

Strange. Maybe I should leave this alone for a while and see where it goes.

[AstroChara]

There is a possible detection of Proxima c through direct imaging. Doesn't appear to be consistent with the astrometric solution to the planet's orbit, but does seem to line up well with the previous paper and ALMA observations. The object's semi-major axis is slightly closer to the star than Proxima c from previous work, at 1.4 or 1.33 AU depending on eccentricity, the latter yielding a lower value for Proxima Centauri's mass, at 0.091+-0.012 solar masses, than the current 0.12 solar masses. Finally, the object appears to be too bright, meaning there is a possibility of circumplanetary material such as a ring system or a dust cloud produced by collisions.

====================

Further out, 130 light-years from Sol, we have TOI-1235 b (paper 1, paper 2), a hot rocky planet orbiting around an early M-type star whose radius puts it in the middle of the Fulton gap - the zone spanning from 1.5 to 2 Earth masses where planets usually become larger through the accumulation of hydrogen and helium or smaller through the loss of aforementioned elements. The paper also mentions another candidate planet, more massive with a minimum mass of 13 Earths and further out at 0.1319 AU.

TOI-1235 b
Semi-major axis: 0.038 AU (calculated by myself, using star's mass cited in the second paper at 0.640 solar masses)
Orbital period: 3.44 days
Mass: 6.91 Earths
Radius: 1.738 Earths

====================

Finally, reanalyzed data from Kepler revealed Kepler-1649c, an Earth-sized planet in the habitable zone of a red dwarf star, very similar to TRAPPIST-1e, although a year on this planet lasts 19.5 days rather than 6.1 days, as its star is more massive, at 0.1977 solar masses. Kepler's previous closest match was Kepler-186f, an Earth-sized planet lingering at the outer edge of the star's habitable zone. The system has another, previously known planet of similar size in closer orbit that gives it Venus-like irradiance. The two planets in this system are linked in a 4:9 mean-motion resonance. The system is roughly 300 light-years away from Sol.

Kepler-1649c
Semi-major axis: 0.083 AU (calculated by myself, using star's mass cited in the paper at 0.1977 solar masses)
Orbital period: 19.5 days
Radius: 1.06 Earths
Irradiance: 0.74 Earths

[QuantumJack1]

TOI 849b, the probably most massive terrestrial planet, is found recently. https://arxiv.org/abs/2003.10314 It has 40.78 earth mass, 3.447 earth radius and 2487 earth irradiance, making it well inside Neptunian desert from midsize and Refractian temperature, but hard to evaporate considering its huge density. It may have a composition of no gas, 85% ice and 15% rock to be classified as MegaTerrestrial Ymirian Pyrohydrothalassic, or some gas, less ice and more rock to become SuperNeptunian Lapicaelian.

[stevebowers]

This planet is dense, but much less dense than one which is only made of rock, so it does probably have an atmospher and/or a large ice component. A hot neptune hyperbaric type, according to NoLWoCS, but an unusual one. It has probably lost a lot of atmosphere, but probably not all. Surface gravity 3.45 gees.

[AstroChara]

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.

[QuantumJack1]

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.