Talk:82 G. Eridani

On 24 September 2012, it was proposed that this article be moved to 82 Eridani. The result of the discussion was no consensus.

Debris disk

Several sources suggest this star has an infrared excess, which may indicate a debris disk. However, beyond that I haven't found much data.—RJH (talk) 22:32, 5 April 2010 (UTC)[reply]

Planetary system

3 planets it's been found around HD20794 (82 Eridani): The HARPS search for Earth-like planets in the habitable zone: I -- Very low-mass planets around HD20794, HD85512 and HD192310 http://arxiv.org/abs/1108.3447 — Preceding unsigned comment added by 189.83.13.45 (talk) 01:00, 18 August 2011 (UTC)[reply]

Original research?

Has luminosity value been reported in a journal or other reliable published source? If so, use the published value and cite the publication. I don't think it's necessarily good practice to add original research by doing calculations and entering them into WP articles. AstroCog (talk) 16:52, 2 November 2011 (UTC)[reply]
I was going to say...
${\frac {L}{L_{sun}}}=\left({\frac {R}{R_{sun}}}\right)^{2}\left({\frac {T_{eff}}{T_{sun}}}\right)^{4}$ where L is luminosity, R is radius and T_eff

is not a reference, even if the formula is known, the unpublished results makes it original research. 24.79.40.48 (talk) 22:50, 10 January 2012 (UTC)[reply]
Let me be clearer, the L=0.62 is all that is necessary even if the figure comes from a paper that illustrates the calculation with a formula. 24.79.40.48 (talk) 22:56, 10 January 2012 (UTC)[reply]

I think it is preferred practice to use a value from a published source. If that is not available and there's a consensus to use a calculation (per WP:CALC), then I'd like to recommend putting in a cite for the formula and show the calculation. That way we know what numbers you used, and we can change the result when the estimates are revised. For example:

{\begin{aligned}{\frac {L}{L_{sun}}}&=\left({\frac {R}{R_{sun}}}\right)^{2}\left({\frac {T_{eff}}{T_{sun}}}\right)^{4}\\&=0.92^{2}\left({\frac {5,401}{5,778}}\right)^{4}=0.65\end{aligned}}

Hmm, it's a different result. Regards, RJH (talk) 23:06, 10 January 2012 (UTC)[reply]

Requested move

The following discussion is an archived discussion of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the proposal was no consensus. --BDD (talk) 16:48, 19 October 2012 (UTC) (non-admin closure)[reply]

82 G. Eridani → 82 Eridani – In my experience this star is usually termed "82 Eridani" rather than the more pedantic "82 G. Eridani". To me the insistence on the "G." form seems quite odd. Certainly SIMBAD lists it as "82 Eri" and the references list there contains papers using "82 Eri" or "82 Eridani" in the title and none with the "G." form. [1] Relisted. Jenks24 (talk) 12:23, 12 October 2012 (UTC) 46.126.76.193 (talk) 19:50, 24 September 2012 (UTC)[reply]

Survey

Feel free to state your position on the renaming proposal by beginning a new line in this section with *'''Support''' or *'''Oppose''', then sign your comment with ~~~~. Since polling is not a substitute for discussion, please explain your reasons, taking into account Wikipedia's policy on article titles.

Weak Oppose it's not a Flamsteed designation. (If it were, it wouldn't have the "G.", which indicates that it isn't) It is a Gould designation. -- 76.65.131.248 (talk) 23:23, 24 September 2012 (UTC)[reply]
- True but in practice the two systems seem to have merged (at least in this case), and while the G. may be more correct, Wikipedia prefers general usage to correctness. 46.126.76.193 (talk) 17:49, 25 September 2012 (UTC)[reply]

Discussion

Any additional comments:

The above discussion is preserved as an archive of the proposal. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Are some planets in the habitable zone?

The article never makes this clear. One scientist speculating about a 5% chance does not represent scientific consensus, nor is it very clear. Is it within the generally theorized habitable zone or not? If not, is it in the theorized border range of a habitable planet? If so what are the specifics? Cliffswallow-vaulting (talk) 07:28, 18 July 2014 (UTC)[reply]

Gliese 139 d

This article on a possible planet in the 82 Eridani system was recently created by User:Jtadesse. I'm redirecting it to here, since this planet isn't clearly confirmed (there are different models of the system in different sources, and this planet only appears in one source so far), and this name also isn't used by any source - the system is commonly referred to as 82 Eridani or HD 20794, not Gliese 139, and the "d" designation refers to a different planet in most sources.

Also, as mentioned at Talk:K2-332 b, much of the article's content is speculation about habitability based on sources not specifically about this planet. This belongs in one of the articles about planetary habitability, if it's not already there.

I would consider the minimum requirements for creation of a separate article on this object to be a second source confirming its existence, and a consensus on its designation, neither of which currently exist. SevenSpheres (talk) 17:37, 24 November 2023 (UTC)[reply]

Table

Might as well do this - here's a table summarizing the history of detections in this system. Only two planets are clearly confirmed, usually called b & d. Currently, the outer candidate discussed above is the only other one that seems likely. SevenSpheres (talk) 04:09, 25 November 2023 (UTC)[reply]

82 Eri (HD 20794) planets
P11^[1]	F17^[2]	L23^[3]	C23^[4]
—	g, 11.9 d?	—^[5]	—^[6]
b, 18.3 d	b, 18.3 d	b, 18.3 d	b, 18.3 d
c, 40.1 d	c, 43.2 d?	—^[7]	—^[6]
d, 90.3 d	d, 88.9 d	d, 89.8 d	c, 89.6 d
—	e, 147 d	—^[5]	—^[6]
—	f, 331 d?	—^[5]	—^[6]
—	—	—	d, 645 d

References

^ Pepe, F.; et al. (2011), "The HARPS search for Earth-like planets in the habitable zone: I – Very low-mass planets around HD20794, HD85512 and HD192310", Astronomy & Astrophysics, 534: A58, arXiv:1108.3447, Bibcode:2011A&A...534A..58P, doi:10.1051/0004-6361/201117055, S2CID 15088852
^ Feng, F.; Tuomi, M.; Jones, H.R.A. (September 2017). "Evidence for at least three planet candidates orbiting HD 20794". Astronomy and Astrophysics. 605 (103): 11. arXiv:1705.05124. Bibcode:2017A&A...605A.103F. doi:10.1051/0004-6361/201730406. S2CID 119084078.
^ Laliotis, Katherine; Burt, Jennifer A.; et al. (April 2023). "Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions". The Astronomical Journal. 165 (4): 176. arXiv:2302.10310. Bibcode:2023AJ....165..176L. doi:10.3847/1538-3881/acc067.
^ Cretignier, M.; Dumusque, X.; et al. (August 2023). "YARARA V2: Reaching sub-m s⁻¹ precision over a decade using PCA on line-by-line radial velocities". Astronomy & Astrophysics. 678: A2. arXiv:2308.11812. Bibcode:2023A&A...678A...2C. doi:10.1051/0004-6361/202347232. S2CID 261076243.
^ ^a ^b ^c Non-detection, but not considered a refutation.
^ ^a ^b ^c ^d Non-detection, not much is said about it.
^ Significant non-detection, rejected as a false positive. Page 44: We assert that the 40 day planet HD 20794 c published in Pepe et al. (2011) is due to stellar activity and not a Keplerian signal as its statistical significance has not increased despite the addition of hundreds of new precise RV data points.

[Pepe2011-1] Pepe, F.; et al. (2011), "The HARPS search for Earth-like planets in the habitable zone: I – Very low-mass planets around HD20794, HD85512 and HD192310", Astronomy & Astrophysics, 534: A58, arXiv:1108.3447, Bibcode:2011A&A...534A..58P, doi:10.1051/0004-6361/201117055, S2CID 15088852

[Feng2017-2] Feng, F.; Tuomi, M.; Jones, H.R.A. (September 2017). "Evidence for at least three planet candidates orbiting HD 20794". Astronomy and Astrophysics. 605 (103): 11. arXiv:1705.05124. Bibcode:2017A&A...605A.103F. doi:10.1051/0004-6361/201730406. S2CID 119084078.

[Laliotis2023-3] Laliotis, Katherine; Burt, Jennifer A.; et al. (April 2023). "Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions". The Astronomical Journal. 165 (4): 176. arXiv:2302.10310. Bibcode:2023AJ....165..176L. doi:10.3847/1538-3881/acc067.

[Cretignier2023-4] Cretignier, M.; Dumusque, X.; et al. (August 2023). "YARARA V2: Reaching sub-m s⁻¹ precision over a decade using PCA on line-by-line radial velocities". Astronomy & Astrophysics. 678: A2. arXiv:2308.11812. Bibcode:2023A&A...678A...2C. doi:10.1051/0004-6361/202347232. S2CID 261076243.

[nd1-5] Non-detection, but not considered a refutation.

[nd2-6] Non-detection, not much is said about it.

[7] Significant non-detection, rejected as a false positive. Page 44: We assert that the 40 day planet HD 20794 c published in Pepe et al. (2011) is due to stellar activity and not a Keplerian signal as its statistical significance has not increased despite the addition of hundreds of new precise RV data points.

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