Wikipedia:Featured article candidates/Epsilon Eridani/archive1

The following is an archived discussion of a featured article nomination. Please do not modify it. Subsequent comments should be made on the article's talk page or in Wikipedia talk:Featured article candidates. No further edits should be made to this page.

The article was not promoted by Nikkimaria 20:39, 16 April 2011 [1].

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Epsilon Eridani

Epsilon Eridani (edit | talk | history | protect | delete | links | watch | logs | views)

• Featured article candidates/Epsilon Eridani/archive1
• Featured article candidates/Epsilon Eridani/archive2

Nominator(s): RJH (talk) 17:33, 4 March 2011 (UTC)

I am nominating this as a featured article because it is an interesting topic about the nearest star system currently known to have a candidate planet. The page has undergone a peer review and is rated as a good article. I'll try to address constructive concerns, but please be specific.

Thank you.—RJH (talk) 17:33, 4 March 2011 (UTC)

Images

• File:Eridanus_epsilon_location.png should have a retouched template
• File:System_Epsilon_Eridani.JPG should have the full photo credit from the source
• File:View_epsilon_eridani_c.png should be described in the caption as a rendering, not an illustration
• File:Ssc2008-19a.jpg - source link is broken. Nikkimaria (talk) 17:49, 4 March 2011 (UTC)

  I have attempted to address your concerns. Let me know if I misunderstood. Thank you.—RJH (talk) 22:43, 4 March 2011 (UTC)

Sources: Perhaps these should be looked at by someone knowledgeable in this field. Certainly, to me they seem to be high quality and reliable, and there are no format issues that I can see. Brianboulton (talk) 23:38, 8 March 2011 (UTC)

• Support Comments - looking over now. Will make straightforward copyedits as I go and jot queries below: Casliber (talk · contribs) 01:55, 9 March 2011 (UTC)

Epsilon Eridani is both smaller and less massive than the Sun - interesting - normally succinct prose would identify the "both" as redundant here...but I am torn as I do feel it ties the two attributes together nicely, so I am just rambling commenting really....

... making it the nearest extrasolar system with a candidate exoplanet. - do we gain anything by using "candidate" over "possible", "probable" or "likely" here? The adjective always reminds me of politics....

'candidate' is fairly common parlance in astronomical journal articles. It seems pretty neutral to me and it doesn't require deducing odds.

ok, i'll pay that. Casliber (talk · contribs) 05:02, 11 March 2011 (UTC)

This observable movement implied a relatively close proximity to the Sun, - why not "This observable movement implied it was relatively close (or near/nearby) to the Sun," (just trying to use shorter words for longer ones if possible as there are alot of long words :))

Fixed.

...excess infrared emissions... - think about where you wanna link "infrared" to and link...and delink subsequent mention in article

Fixed.

as novae explosions - wierd use of plural in adjective - surely it'd be "as explosions of novae" or "nova explosions"?

Fixed.

close proximity of this star - tautological - why not just "proximity" or "closeness"?

Fixed.

m sin i - link to sine (?) or subheading within?

Linked.

given we're talking about planetary habitability etc. I do think the age is worth mentioning in the lead.

This is already mentioned in the third sentence.

ok. Casliber (talk · contribs) 05:02, 11 March 2011 (UTC)

Otherwise looking pretty good....Casliber (talk · contribs) 03:10, 9 March 2011 (UTC)

Thank you for the review.—RJH (talk) 19:12, 9 March 2011 (UTC)

• Comment from the nominator—As there haven't been many comments after two weeks, I'd like to request that this FAC remain on the list for a while longer to see if any other issues get captured. Thank you kindly.—RJH (talk) 19:32, 18 March 2011 (UTC)

RJH, might I suggest posting a neutrally-worded request for review at a relevant WikiProject, or on the talk page of a subject-matter expert? This would help with more specialized review, and would address Brian's post above about having sources reviewed by someone more knowledgeable in this field. Nikkimaria (talk) 14:50, 21 March 2011 (UTC)

Per our usual practice, I did post a notice on WikiProject Astronomical objects back on March 4th. But I think that those members who are going to comment on the article already did so during the PR and GA processes. Thanks.—RJH (talk) 15:06, 22 March 2011 (UTC)

Maybe a post to Wikipedia talk:WikiProject Astronomy would get more eyes on this? Also, even if editors have reviewed the article at GA and peer review level, there is nothing wrong with asking those editors to take another look, particularly if there have been changes since they last looked at the article. Even just a note from them saying that they support per the reviews they did earlier, and that they've looked at the changes and support the changes, would help. Carcharoth (talk) 09:03, 2 April 2011 (UTC)

Most participants are members of both projects. If this is to go down for lack of support, then so be it. I do appreciate the time people spent reviewing the article; that was my primary goal in the nomination. Regards, RJH (talk) 19:02, 2 April 2011 (UTC)

Section break 1

Comments

• This article uses both British and American spellings, and should be standardized on one or the other (see WP:ENGVAR)
  • Sorry but I'm not seeing what you mean. Could you be more specific please?
    • For example, "kilometers" is the American spelling, whereas "millimetre" is British. Nikkimaria (talk) 02:36, 26 March 2011 (UTC)
      • Actually, "millimetre" is the SI spelling. This is used per the "international scope" guidelines in WP:UNITS. It's unfortunate that the US hasn't adopted it yet, but I wasn't really trying to mix US and British spelling.
• "with a lower enrichment of elements other than hydrogen or helium" - meaning not clear. Do you mean it has a lower level of other elements than the sun?
  • Yes. I added clarification.
• In general, this article could be made more accessible to non-specialist readers.
  • Is the problem with some of the technical wording? It's hard to know how far to take that; the links provide more information and many of the technical terms used do also include an explanation.
    • Technical wording, and also what you assume the reader already knows - which in my case, unfortunately, isn't much. Nikkimaria (talk) 02:36, 26 March 2011 (UTC)
      • Okay, I tried to add further clarification for a number of terms that seemed technical in nature, or at least obscure. Not sure how to judge my success though without further feedback. Thanks.—RJH (talk)
• Wikilinking needs work. Don't link very common terms, link potentially unfamiliar terms on first appearance, and don't relink terms in close proximity. Also, even when a term is linked it's often helpful to provide a brief explanation for the benefit of the non-specialist reader
  • I cleaned up some of them, but I think most are still needed. See previous answer.
• Manual of style edits needed, particularly hyphen/dash use
  • As far as I could see, the hyphen/dash use is correct. The script has been run through BrighterOrange's script. The only error I could find was due to a template, which I attempted to fix.
    • Unfortunately scripts aren't equipped to pick up on nuances of usage. For example, ranges expressed with prepositions (like "from 1980–2000") should not use a dash. Nikkimaria (talk) 02:36, 26 March 2011 (UTC)
      • Do you perhaps mean "Luyten 726-8"? Sorry but this is the standard Luyten catalogue nomenclature; it's not really a range. All of the numerical ranges use en-dashes. I did find one negative number that was using a dash instead of a −, so that one is fixed.—RJH (talk)
        • No, I mean "from 1980–2000" and similar. Nikkimaria (talk) 17:12, 26 March 2011 (UTC)
          • Here are all of the ranges used in the article: 1881–3, 1980–2000, 700–850, 35–100, 0.10–0.15, 0.5–1.0, 0.6–1.4, 35–75. Those all comply with WP:ENDASH because they all use en-dash to stand for to or through in ranges. I remain unclear about what issue you are seeing. Perhaps there is a font issue with your browser? They all look like en-dashes to me. Thanks.—RJH (talk)
• "with Nova Cygni 1975 being used as the timer" - what does this mean?
  • Clarified, I hope.
• "The following year, this star was proposed as one of the targets for Project Daedalus of the British Interplanetary Society" - what came of this proposal?
  • It was only a paper study, so I tried to clarify that.
• "with its chromospheric abundance of iron estimated at 74% Solar" - phrasing
  • Clarified.
• "The spatially averaged magnetic field strength of this star" - meaning?
  • I clarified the wording.
• Provide conversions for metrical measurements
  • Do you mean to old English? Metric is the scientific standard. Please see WP:UNITS: "In scientific articles, use the units employed in the current scientific literature on that topic." Otherwise, I'm not sure what you need here.
    • The introduction to that section specifies that metric appears first (the primary unit), but also "Where English-speaking countries use different units for the same measurement, follow the "primary" unit with a conversion in parentheses". Nikkimaria (talk) 02:36, 26 March 2011 (UTC)
      • I'm just starting to look at this article, but there are some instances where conversion makes little sense, particularly if the unit is a modern one. In the infobox, for example, there is little sign of conversions, and I think that is a good thing. Requiring everything to be expressed in two units can be taken too far. Also, it could be argued that in astronomy, English-speaking countries don't use different units here. Everyone uses metric, and I think you would struggle to find star distances and radial velocities (for instance), commonly expressed in imperial units. It is far more common to express them in metric units or in units specific to the field (e.g. AU or parsec or light-year). Would it help if all the instances of units were listed somewhere to be discussed? Carcharoth (talk) 08:14, 26 March 2011 (UTC)
        • Yes, in astronomical articles it has just been a convention to only use Old English units in situations that the reader might directly experience. Thus, Fahrenheit is used for Earth-like atmospheric temperatures, but you would never use it to describe the surface temperature of a star; at least not in a scientific article. Anyway, if I put conversions in there, past experience has shown that they would likely get stripped out later.—RJH (talk) 17:02, 26 March 2011 (UTC)
• "The structure of the belts and the dust disk suggests the presence of three planets in the Epsilon Eridani system" - okay, but you've previously only mentioned two potential planets, where's the third? Nikkimaria (talk) 16:02, 21 March 2011 (UTC)
  • This is also alluded to in the "Epsilon Eridani c" section. I modified it to say "more than two planets" as the actual number remains uncertain.—RJH (talk)

  Thank you for the review.—RJH (talk) 15:52, 22 March 2011 (UTC)

Section break 2

Comments

• The names of the various researchers mentioned lack context. The reader currently needs to click through to the individual articles to see the nationality or profession of the researchers. "US astronomer Artie Hatzes" and "German celestial cartographer Johann Bayer" and "English astronomer John Flamsteed" and so on, all read better to me than just the bare names.
  • Thanks. In the past I've had mixed feedback about listing the nationalities and professions of the people mentioned. I'll go ahead and add the information, but I think the jury is still out on this. Shrug.—RJH (talk)
• In the 'Properties' section you say "With a declination of −9.45°, Epsilon Eridani can be viewed from much of the Earth's surface." - this is something I was expecting to see in the lead - where on Earth can you view this star from, and roughly where in the celestial sphere it appears relative to other constellations. Not everyone will know where Eridanus is.
  • Actually, I think the map at the top of the article does a decent job of showing the location. The information on viewing Eridanus should really be on the constellation article. Is that reasonable? Even the FA'd Sirius article doesn't provide a viewing "how-to" in the lead. I think it should probably be left to astronomy guides.—RJH (talk)
• Is it possible to say anything about prehistoric observations of this star? Do we know for sure whether it is one of the stars included in the ancient forms of the constellation Eridanus?
  • Unfortunately not. It just isn't a prominent star visually, so it never appears to have accumulated much mythology. The star only became notable during the modern era.—RJH (talk) 16:33, 26 March 2011 (UTC)
• In the 'Kinematics' section, I was trying to work out from the figures provided, its orbital speed in km/s around the Milky Way's centre. Does it make sense to provide that figure or not? To help people work things out, could you also say whether it is moving in the plane of the Milky Way, up or down, and whether it is moving in the same direction as the Sun around the Milky Way? I think the "(U, V, W) = (−3, +7, −20)" answers those questions, but it would be nice to unpack that and explain it a bit more. i.e. build up a mental picture of how this star is moving relative to our Sun, and how both are moving relative to the rest of the Galaxy. Also, it is common to talk about how the Sun has orbited the Milky Way x times since it formed - have any sources calculated similar things for this star?
  • Ah, well, giving a net velocity through the Milky Way based on the space velocity would require a calculation by us. Unfortunately the source didn't give the maximum distance out of the Milky Way plane, nor the number of times it has traveled about the galaxy. I think these two would also require calculations on our part. While interesting, I'm not sure that including these would be appropriate without a source.—RJH (talk)
• 'Dust disk' section: "Observations with the James Clerk Maxwell Telescope" - it would be good to give the year here. Or if the year is not certain, say when the research was published (I assume 1998). If there are other areas of research that can be similarly dated, that would help give the narrative some flow.
  • Added.
• The two notes appear to be calculations. Are these calculations you have done or are they calculations that others have done? If the former, are the calculations allowed by WP:CALC?
  • Only the second note is a calculation. For ease of confirmation, I provided full details of the calculation and a citation for the formula. For me it is a routine calculation and the numbers and results were checked during an earlier review. If you feel it necessary, I can remove it and the computed net motion. This would just mean the reader would have to deduce it from the two components of proper motion.—RJH (talk)

May have more comments later, as this is one article I'd like to take the time to read through thoroughly. Carcharoth (talk) 09:03, 23 March 2011 (UTC) Updated: 08:49, 26 March 2011 (UTC)

• • Thank you for your review thus far. Please let me know if there is anything else I might address.—RJH (talk) 17:41, 24 March 2011 (UTC)

Section break 3

Comments

• I'm confused by the first paragraph of the lead (which is fundamental to describing what it is). 'Epsilon Eridani is a star' (singular) followed by 'it is the third closest star system (plural?) visible to the naked eye. Is Epsilon Eridani the name of the system or a single star? The redirected piped link goes to a list of stars not systems, perhaps that article needs clarifying? Are the system stars visible to the naked eye or just the one star?
  • I'm not the nominator (I'm another reader of the article), but I too am not sure what is meant here. I can, however, see the potential for confusion when using the terms "star system", "stellar system" and "planetary system". One of the sources here uses the term 'stellar system' as in "Project Daedalus - The ranking of nearby stellar systems for exploration". The 'Properties' section says "ninth nearest stellar system". This article uses the term 'star system' several times: in the lead, in the 'Kinematics' section, and in two of the footer templates - the term is also used in one source ("The One Hundred Nearest Star Systems") and in an external link ("Astronomers discover a nearby star system just like our own Solar System"). The term 'planetary system' is used in the article and in one of the sources here ("Closest Planetary System Hosts Two Asteroid Belts"). I had always personally used "planetary system" to refer to the planets and other bodies around a star, "solar system" to refer to the Sun and its planets and other bodies, and "stellar system" to refer to other stars and their planetary systems if they have them (the logic being that you replace 'solar' with 'stellar'). Things like double stars and so on, I suppose could be star systems, but I'd never heard of them referred to this way. I suppose a lone star without planets could also be a star system, but it seems simpler to call it a star. Having said that, I doubt any star lacks other bodies orbiting it, so in some ways it makes sense that all stars are part of a star system. Indeed, our article on 'star system' says "Star system may also be used to refer to a system of a single star together with a planetary system of orbiting smaller bodies." As far as I know, Epsilon Eridani is a single-star star system. Obviously if the sources use terms in contradictory ways (I hope they aren't doing this), then you can't avoid confusion, but the article text should be consistent. Carcharoth (talk) 05:22, 24 March 2011 (UTC)
    • Reworded.—RJH (talk)

• How many stars are known to be in the system? 'Only 10.5 light years away', seems a long way to me! Needs to be put in relative terms. How bright is it? Magnitude or brightness does not seem to be mentioned in the lead, I see it in the infobox but that could/should be described in words somehow as a descriptive feature of what an observer might expect to find.
  • Tried to address this.—RJH (talk)

• Would Spectral class K2 mean that it is orange in colour? That link could be anchored directly to the K2 section of that article could it not? Seems to me that the lead needs to be generalised for the lay reader or use the technical terms plus an explanation.
  • Added some explanation.—RJH (talk)

I've not looked at the rest of the article, I have experience of astronomy and would like to help more in this area of WP, assuming that I don't get my head bitten off here! Nimbus (Cumulus nimbus floats by) 00:34, 24 March 2011 (UTC)

You might want to familiarize yourself with the FAC process, the FA criteria and the types of things that reviewers look for in an article. :-) —RJH (talk)

• Question this is the third closes star, and probably among the 10 brightest ones... and there is no actual picture of it???? Nergaal (talk) 06:25, 25 March 2011 (UTC)
  • Yes but, given current technology, all you're going to see at present is a faint point of light. (For example.) There is a submillimetre shot of the debris disk, but I had concerns about the licensing.—RJH (talk) 15:47, 25 March 2011 (UTC)
  • I agree that an image that looks like a star might enhance the article. Googling around did not give me anything licensed for our use. The Hubble site has no telescopic images of this star. The more scientifically important image could be the one at http://outreach.jach.hawaii.edu/pressroom/1998_epseri mentioned by RJHall. This image shows the star and its dust cloud in the submillimeter radio spectrum. A person who might be able to release it is Jane S. Greaves of the University of St. Andrews. She has a web page at http://star-www.st-and.ac.uk/~jsg5/ which includes an email address. EdJohnston (talk) 23:56, 26 March 2011 (UTC)
    • Thanks. Yes, I have that article linked in the External links section.—RJH (talk)
      • I cannot believe that there are no decent images of this star. Its apparent magnitude of 3.7 is gianormously bigger than the likes of Haumea (apparent ~17), which do have some pictures. Nergaal (talk) 05:11, 29 March 2011 (UTC)
        • There were none that I could find, besides the above. Images of Haumea may be available precisely because it was so hard to find, and because they show the moons and/or the current position. It would require much higher resolution to show the planets, if any, around Epsilon Eridani, and the star doesn't move anywhere near as much. Therefore, the images of this star are less interesting.—RJH (talk) 15:34, 29 March 2011 (UTC)
• http://planetquest.jpl.nasa.gov/atlas/atlas_profile.cfm?Star=105? Nergaal (talk) 16:59, 29 March 2011 (UTC)
  • Yes, that's an "image". It doesn't appear very interesting and is somewhat ugly.—RJH (talk) 17:21, 29 March 2011 (UTC)
• Comment since it is such a close star, I would be interested to see a separate section on proposed exploration (besides that done by telescopes). Nergaal (talk) 17:46, 28 March 2011 (UTC)
  • I'm set against this idea because the same information applies to multiple nearby stars. Whatever could be said on the topic is already covered by the Interstellar travel article; or should be. This article already mentions of the star being one of several nearby candidates of interest, so I think that is more than sufficient.—RJH (talk) 15:29, 29 March 2011 (UTC)

Lead is tasty.

• "Its rotation period is a relatively rapid 11.2 days, although this varies by latitude." If the rotation period varies by latitude, then how can it be definitively described by one number? Perhaps "Its average rotation period is a relatively rapid 11.2 days, although this varies by latitude." ?
  • Okay.
• "In addition, Epsilon Eridani harbors an extensive outer debris disk corresponding to the Solar System's Kuiper belt." I don't think "corresponding" is the right word here. How about ", similar" instead?
  • Well, 'corresponding' means having the same relationship; 'similar' would mean the two are nearly a physical match, which they aren't.
• I think the lead should mention the star's potential for supporting life, as that is one of its most interesting features.
  • I added a mention in the same sentence as 'SETI', which seems appropriate.
• The lead should also answer the question: "How long have we known about this star?"
  • I added a sentence about when the star received its name.

--Cryptic C62 · Talk 21:55, 3 April 2011 (UTC)

• • Thanks.—RJH (talk)

Section break 4

It is likely that Epsilon Eridani is of most interest to both astronomers and the public due to the possible planets. I suggest that the lead could be revised to pull that information into the first paragraph, per don't bury the lead. Here is what would happen if the star's technical details (in pgph 1) were swapped with the planet information from pgph 2. I have highlighted in green the material that got moved forward in this draft:

Epsilon Eridani (ε Eri, ε Eridani) is a star in the constellation Eridanus. At a distance of 10.5 light years (ly), it has an apparent magnitude of 3.73 and is the third closest of the individual stars or star systems visible to the naked eye. Its age is estimated at less than a billion years. The motion of this star along the line of sight to the Earth, known as the radial velocity, has been observed for more than twenty years. Periodic changes in this data yield evidence of a giant planet orbiting Epsilon Eridani, making it the nearest extrasolar system with a candidate exoplanet. This unconfirmed object, conventionally known as Epsilon Eridani b, was formally announced in 2000 by a team of astronomers led by Artie Hatzes. Current data indicate that this planet orbits with a period of about 7 years at a mean separation of 3.4 astronomical units (AU), corresponding to 505 million kilometers. However, the existence of the proposed planet is not universally accepted because the radial velocity data contain a high level of background noise from the star's magnetic activity.

Because of its youth, Epsilon Eridani has a higher level of magnetic activity than the Sun, with a stellar wind 30 times as strong. Its rotation period is a relatively rapid 11.2 days at the equator, although this varies by latitude. Epsilon Eridani is both smaller and less massive than the Sun, with a lower enrichment of elements other than hydrogen or helium compared to the Sun. Astronomers categorize it as a main-sequence star of spectral class K2, which means the energy being generated at the core through nuclear fusion of hydrogen is emitted from the surface at a temperature of about 5,000 K, giving the star an orange hue.

If this were done, some reorganization should be attempted as well. In our article on the possible planet Epsilon Eridani c, the star is called an orange dwarf. Is that correct? The star is not called an orange dwarf here. I suggest that 'conventionally known as Epsilon Eridani b' should drop the 'conventionally', which adds no information. EdJohnston (talk) 21:56, 4 April 2011 (UTC)

Well... From my perspective, putting information about the primary topic of the article second would would be burying the lead.

I understand the natural enthusiasm about planetary systems and possibility of extraterrestrial life, but really the article is about the star and that should be presented first. If reviewers are enthusiastic about the topic of extraterrestrial life, then I would recommend that they try to bring that article up to FA standard rather than seeking to use this article as a promotional page. :-)

The use of "orange dwarf" is rare and is not proper astronomical parlance. It is better to call it a K-dwarf, a K-type dwarf, a K-type main-sequence star, &c. The orange hue is mentioned at the end of the first paragraph, where it is attributed to the temperature. Thanks. Regards, RJH (talk) 22:08, 4 April 2011 (UTC)

Section break 5

Support with comments following. Caveat: I'm a planetary person rather than stellar, and I'm not an exoplanet specialist. I would suggest asking User:Mike_Peel to take a look; he does galactic, but he might be aware of some other folk who work on stars who could look it over.

Lead Structure is good.

• "Because of its youth, Epsilon Eridani has a higher level of magnetic activity than the Sun, with a stellar wind 30 times as strong." Is a comparison to the Sun valid for a K2? Could just say its activity is 30 times higher than the Sun at present.
  • I changed it to say "the modern Sun".
• Probably leave the rotation period and its latitude variation to the body text, where it can have a fuller explanation.
  • Okay.
• "has been observed for more than twenty years." If that does make it one of the longest-observed stars, mention that as an interesting point.
  • This may be difficult to determine and properly reference. To me it only seems interesting because it spans multiple orbits of the candidate planet, presumably reducing the error margin.
• "outer debris disk corresponding to the Solar System's Kuiper belt" While this statement is correct, could probably just say "of remnant planetesimals from the system's formation" to keep it more general for the lead.
  • Okay.
• Worth mentioning its origin in an open cluster? ie. it began life in an open cluster and is now part of the UM Moving Group.
  • Done.

Observation history

• Break out the debris discovery into a subsection, since SETI is also sectioned.
  • Done.
• Aggressively trim down the SETI material. eg. Habitable Planets for Man could be much shorter. This section is overly long and needs to be more succinct: eg. discuss that the star has been monitored by SETI searches in radio at 21-cm and in microwaves. Less telescope detail.
  • I did some trimming, but I'm reluctant to make further cuts because of past interest by other editors.

Properties

• Intrigued that its metallicity is < solar if it's younger than the Sun. Any comment? Also, how does its metallicity compare to the other members of its Moving Group? No chemical studies made?
  • Yes I also found that interesting, but I only found one study that attempted to address it. The abundance of iron in the UMa group is reported as below solar,[2] although not as much as for this star.
• Actually, the discussion of metallicity seems a little scattered. Consider if there's a way to pull that closer together.
  • The metallicity is in two parts; the first discussing the physical properties of the star and the second discussing the age anomaly. I'm not sure that bunching those together would help the flow, as the sections are organized at a higher level.
• Clarify the first two paras of Magnetic activity. If it's a BY Drac, say it is a BY Drac variable because of... and pull together the magnetic information - it just needs better sequencing through there, though some of the prose phrasing is nice.
  • Okay, I re-organized the material.
• "At its estimated distance from the Earth, this astrosphere would span an angle of 42 arcminutes" clarify as "If visible to the human eye, this would span" or suchlike.
  • I removed the "would".
• "Luyten 726-8 may penetrate a conjectured Oort cloud about Epsilon Eridani, which could gravitationally perturb some comets with long orbital periods." Rephrase. "If e Eri has an Oort cloud of comets, Luyten 726-8 could perturb..."
  • Fixed.

Planetary system Halfway through this - will revisit to conclude review. Looks very nice so far, excellent explanation of m sin i and the accompanying issues. Iridia (talk) 04:57, 5 April 2011 (UTC)

Thank you for the review thus far.—RJH (talk) 15:38, 5 April 2011 (UTC)

Concluding my comments picking up where I left off...in Planetary system. Iridia (talk) 06:12, 13 April 2011 (UTC)

• I agree with Icalanise that the order in this section now feels awkward. I would place the dust disk subsection before the planets section. That will preserve order in things like the explanation of resonance, which is otherwise first introduced baldly at e Eri c.
• I would not say that objects in the 3:2 resonance are plutinos. Those are a distinct dynamical population in the Kuiper belt. They do not necessarily map to an extrasolar system.
• Will leave off until you've made the changes to the last para of Dust disk. These aren't too major changes: a section rearrangement and followthrough on the suggestion by Icalanise to incorporate the new paper published this March (during this FAC!). Delegates: I'd recommend continuing the nom at this stage. Iridia (talk) 06:12, 13 April 2011 (UTC)

I'm seeing this as a major rework of the article. It will require time to perform this properly and the article will need another review cycle. Ergo, it will need to be taken back through PR and then through FAC. Sorry.—RJH (talk) 14:50, 13 April 2011 (UTC)

RJH, I'm unclear what you're saying above-- are you withdrawing the nomination or disagreeing with the reviewer? SandyGeorgia (Talk) 00:19, 16 April 2011 (UTC)

SandyGeorgia, please withdraw the nomination. Implementing these suggestions may result in significant changes to the article, which I expect will then require another pass through the review cycle. Thank you. Regards, RJH (talk) 17:46, 16 April 2011 (UTC)

Comments. As always, feel free to revert my copyediting. Please check the edit summaries. - Dank (push to talk) 02:30, 10 April 2011 (UTC)

• "the minimal distance": does "a minimum distance" work, or is "minimal" more common in astronomy? - Dank (push to talk) 03:57, 10 April 2011 (UTC)
  • Yes, 'minimum' is closer to the correct meaning. I changed it.
• There's an active merge suggestion in Epsilon Eridani#Epsilon Eridani c, and I see you support the merge. Has that information been added to this article yet?
  • That activity is independent of the FAC. I've been treating it as still under discussion.
    • I don't see it as independent, for two reasons: we generally don't promote when there are active tags on a page, and if this article needs to have material it doesn't have (for any reason), then it doesn't meet FAC's "comprehensiveness" criterion. Can you at least take a guess what material you want to include, and try to include it, even if you self-revert afterward? - Dank (push to talk) 17:44, 10 April 2011 (UTC)
• Otherwise, I'm finished with copyediting, and plan to support. - Dank (push to talk) 12:28, 10 April 2011 (UTC)
  • Thank you for the review and the edits. Regards, RJH (talk) 17:25, 10 April 2011 (UTC)
• Note to delegate: the request to merge material into this article was recent; if possible, give RJH a little time to work on this. - Dank (push to talk) 17:44, 10 April 2011 (UTC)
  • I made a good faith effort to merge all of the significant material that was properly sourced on the planet article. (Most of the remaining material is already in the Epsilon Eridani article, and the remainder is unsourced.) This allowed me to remove the merge tag from the nominated article. I'll move the useful unsourced entries to the talk page for future processing. Thanks. Regards, RJH (talk) 18:19, 10 April 2011 (UTC)
• Support on prose per standard disclaimer. These (plus one) were my edits. - Dank (push to talk) 18:53, 10 April 2011 (UTC)

• Comments - coming at this from a primary interest in exoplanetary systems. Icalanise (talk) 22:31, 10 April 2011 (UTC)
  • "The nearby star Luyten 726-8 will have a close encounter with Epsilon Eridani in about 31,500 years when they will be separated by about 0.93 ly." — Luyten 726-8 is a binary star system. Maybe worth mentioning that one of the components is UV Ceti, a designation which may be somewhat better-known than the designation for the system as a whole.
    • Added.
  • "system includes two debris belts composed of rocky asteroids: one at about 3 AU and the second at about 20 AU, whose structure may be maintained by a hypothetical second planet, Epsilon Eridani c." — I suggest taking a look at Reidemeister et al. (2011) [3] - this is not as clear-cut as was initially made out in the Spitzer news release. Note this paper is currently cited as reference 82 in the debris disc part of the article (although its implications with regard to the two asteroid belts model are not discussed), currently with a reference only to arXiv, this should be updated now the paper is published.
    • Yes that does potentially throw a bucket of cold water on the whole multiple asteroid belts concept. It may take a fair amount of rework to properly fit this into the article, at least within the time remaining. At this point I think the FAC should be rejected so this issue can be properly addressed. Thanks for pointing this out. I did address the citation format. Regards, RJH (talk) 16:14, 11 April 2011 (UTC)
  • Regarding Epsilon Eridani b, it should probably be mentioned that the Benedict et al. (2006) results used astrometry as well as radial velocity.
    • I'm not clear what this would add to the article, since the reference is only being used to cite the predicted planetary properties rather than discuss how they were derived.
      • Well there is a discussion about the mass/inclination degeneracy that limits radial velocity detections in the article. Therefore it is probably worth mentioning that astrometry resolves this degeneracy so you can get the true mass of the planet. Icalanise (talk) 17:45, 11 April 2011 (UTC)
  • "Thus, a terrestrial planet would be subject to bombardment similar to what happened to the Earth during its first 600 million years with the Late Heavy Bombardment." — the reference at the end of this sentence deals with dust ring morphology and doesn't seem to have anything to do with impact rates in the inner system.
    • You're right. It appears that the Aguilar and Pulliam (2008) news release discussed the possibility of a Late Heavy Bombardment, but they did not directly connect it with the proposed ε Eri c planet.
  • I disagree that potential habitability (and hypothetical future exploration, which is also included in the section) should be discussed before the debris system, it is as though this speculation is more important than the genuinely observed properties of the system, but maybe that's just me.
    • Well I agree with you and that was the original arrangement of the two sections (Possible planets/Dust disk). However, it was subsequently re-organized by another editor so I think this would first need to be discussed on the article talk page.
  • "However, the presence of a large planet with a highly elliptical orbit in proximity to the habitable zone of the star reduces the likelihood of a terrestrial planet having a stable orbit within the habitable zone" — given the uncertainties in the orbit of candidate "b", how relevant this is may not be so clear-cut.
    • I pulled the paragraph, since, per the earlier point, it might be WP:SYNTH.

Thanks for the review.—RJH (talk)

Sources Sorry, I realize Brian gave this his ok above, but I can see some formatting inconsistenices that could be cleaned up; this is just a sampling, but the references should be scrubbed for similar formatting issues throughout: Sasata (talk) 18:09, 13 April 2011 (UTC)

• there's a mix of sentence case and title case for the journal article titles—this should be consistent
  • I've attempted to fix this. RJH (talk)
• similarly, should be consistent about whether the month is given with the year published
  • I added additional date information where available.
• The archive id for ref #6 (van Leeuwen 2007) is not working. Why are the volume/issue/pages not the same as indicated in the Bibcode link?
  • Fixed.
• spacing between author initials is not consistent
  • Fixed (single instance).
• (re: ref 12, Saumon 1996): what's the point of giving links to both the doi and the arXiv when they both lead to the same page? (other refs have same issue)
  • It is possible the destination for the doi may change, depending on the publisher.
• issue # is not always given when available (see for ex, refs 14 &16, among others)
  • I fixed it where I could find it.
• publisher location for Boyle 2009? Belkora 2002?
  • My understanding was that the location is needed if the ISBN is not available.
• Retrieval dates not required for web-versions of print sources (like Google Books, ref #29)
  • Book scans are sometimes removed from Google.

Thanks.—RJH (talk) 21:48, 13 April 2011 (UTC)

Withdrawn by nominator. Nikkimaria (talk) 20:38, 16 April 2011 (UTC)

The above discussion is preserved as an archive. Please do not modify it. No further edits should be made to this page.