Talk:Solar analog

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Definition[edit]

I'm curious what others think of using the definitions from The Second Annual Lowell Observatory Fall Workshop for this page. These are:

  • Solar-Type: 0.48 to 0.80 in B-V (roughly equivalent to F8 V—K2 V)
  • Solar Analog
    • Temp. ± 500 K solar (roughly 5200—6300 K)
    • Metallicity 0.5—2.0 solar
    • No close companion (that is, a companion with an orbital period of 10 days or less)
  • Solar Twin
    • Temp. ± 10 K solar
    • Metallicity 0.89—1.12 solar
    • No companion
    • Age ± 1 Ga solar (3.59—5.59 Ga)

Pfhreak (talk) 02:08, 9 January 2008 (UTC)[reply]

Yes, a useful link you've got there. ~10 K solar! Wow: is any star going to meet this? If 18 Scorpii really is exactly 5800 K, it's at least within the low double digits but still wouldn't be a twin. Conversely, variability gets no mention. Marskell (talk) 12:44, 30 January 2008 (UTC)[reply]
A good point about the temperature range. Maybe ± 50 K solar (roughly 5720—5830 K) would be more realistic, and it would still be an order of magnitude more precise than the temperature range for analogues. Pfhreak (talk) 17:05, 30 January 2008 (UTC)[reply]
I had the same thought. Feel free to make the addition, BTW. You might see Margaret Turnbull for more. Marskell (talk) 15:57, 31 January 2008 (UTC)[reply]
A first draft, after much delay, is available for feedback at: User:Pfhreak/Solar Twin Pfhreak (talk) 18:05, 26 February 2008 (UTC)[reply]

No star satisfies the criteria for solar twin[edit]

If you take a look at Meléndez, and Ramírez (2007), then really no star known satisfies the criteria of being a solar twin.—RJH (talk) 19:33, 12 May 2010 (UTC)[reply]

    • I agree this page was very confusing (and still maybe). But to help, I have added "Highlighted boxes are out of range for a solar twin, but the star may have been noted as solar twin in the past.". I then highlighted the boxes that are out of spec. I have found that some stars have been called a "solar twin", but later it was found to be too far out of range to qualify. Because it was called a "solar twin" in the past, many do not want the star to not have that title anymore. I did remove stars that are in binary star systems, as this was already noted in the text as disqualifying the star. Binary star systems classification does not change over time, like temp, age and FE can, with better measurements. Thank you for the feedback. Telecine Guy (talk) 19:04, 28 September 2016 (UTC)[reply]

Why is the Sun on the Chart?[edit]

Why on earth do we include the Sun with Sunlike stars? You'd think this would be tautologically obvious. —Preceding unsigned comment added by 128.113.90.66 (talk) 21:27, 4 March 2011 (UTC)[reply]

We include the Sun so that the reader has a baseline to compare with the respective parameters of the other Sun-like stars.—RJH (talk) 22:48, 4 March 2011 (UTC)[reply]
Yes, the Sun needs to be there, it is the standard. Telecine Guy (talk) 19:04, 28 September 2016 (UTC)[reply]

Added footnotes with links to SIMBAD etc[edit]

Hi, I've made a new template {{CelestialRefAll}} and I thought it's about time to use it in some main space articles to see if that turns up anything.

So have tried it here first. Interested in any thoughts about it. Thanks! Robert Walker (talk) 11:32, 25 July 2013 (UTC)[reply]

Suggestion, to have more about why these stars are interesting[edit]

Hi, I think it might be an idea to say a bit more about why solar twins and analogues are so interesting.

I wrote a section about it here in the article for HD 133600 using material from a 2007 paper by Jorge Melendez and Ivan Ramırez which has a good introduction that goes into it in some depth, why they are useful. [1].

I'm sure there is a lot more that can be said. Robert Walker (talk) 11:38, 25 July 2013 (UTC)[reply]

Define twin[edit]

Article text as of July 17, 2016: "To date no solar twin with an exact match as that of the Sun has been found, however, there are some stars that come very close to being identical to that of the Sun, and are such considered solar twins by the majority of the public. An exact solar twin would be a G2V star with a 5,778K temperature, be 4.6 billion years old, with the correct metallicity and a 0.1% solar luminosity variation"

The above odd wording is correct. No exact match of the Sun has been found after about about 2.5 million stars have been studied and logged. Thus, the word twin has been redefined. "twin" is normally defined as "resembling each other", "being identical". As no other G2V star with a 5,778K temperature, 4.6 billion years old, with the correct metallicity (Z = 0.0122) and a low 0.1% solar luminosity variation (over a 11 year span), has been found; the word "twin" has been redefined to a much wider definition, more like the word "vaguely close". Telecine Guy 01:12, 18 July 2016 (UTC)

References[edit]

  1. ^ HIP 56948: A SOLAR TWIN WITH A LOW LITHIUM ABUNDANCE , Jorge Melendez and Ivan Ramırezd, The Astrophysical Journal, 669: L89–L92, 2007 November 10. (also discusses HIP 73815, compares it with HIP 56948)

"Oldest" Solar Twin[edit]

This might be useful: http://www.eso.org/public/news/eso1337/ Oldest solar twin out there that found — Preceding unsigned comment added by Peterooch (talk • contribs) 09:22, 29 August 2013 (UTC)[reply]

  • Sorry this silly, if you are much older, you cannot be a twin. Twins have the same age. The title should be "look what the Sun may be like in the future". Telecine Guy (talk) 21:39, 8 May 2017 (UTC)[reply]

"Solar Twin Table does not agree with criteria[edit]

Most of the stars shown in the table for 'Solar Twins' fail to meet the criteria listed above the table so should not be in there.

I beleive only HD 143436 and HD 101364 meet the criteria in all respects. All the values with a buff backgrond result in failing the criteria. I presume the buff are edits but it is not explained on the page or as far as I could see in the history.

Should all the failing stars be moved to Solar Analogues or should the criteria be changed ?

John Murrell

86.174.193.152 (talk) 16:19, 4 January 2014 (UTC)[reply]

This is explained within the article: "The following are the known stars that come closest to satisfying the criteria for a solar twin". The solar twin criteria are very strict, so it stands to reason that not many true examples are currently known. --203.57.209.105 (talk) 09:58, 15 September 2014 (UTC)[reply]
I agree, very confusing, why list the criteria to be on the list and then not follow the criteria? What is "close", who defines "close". It is like saying "I have twin brother, but he is 10 years younger than me and has different color hair." It is silly. Telecine Guy 00:44, 18 July 2016 (UTC)
See above No star satisfies the criteria for solar twin. I have added "Highlighted boxes are out of range for a solar twin, but the star may have been noted as solar twin in the past.". I then highlighted the boxes that are out of spec. I hope this helps as I agree with John Murrell the charts were very confusing and not good. Telecine Guy (talk) 19:13, 28 September 2016 (UTC)[reply]

Goromladen[edit]

Removed the following unsourced line from the table. Web searches show no results apart from mirrors of this page.

|- |style="text-align:left;"| Goromladen | | | 200 | G2V | 5,778 | 0.00 | 4.6 |

I was about to do this myself, as the details given were obviously copied from those of the Sun, so thanks. It's a good idea to sign your talk page comments though. --203.57.209.105 (talk) 10:00, 15 September 2014 (UTC)[reply]

Solar-Type Stars[edit]

What definition are we using - a B-V value of 0.48 to 0.80, or 0.50 to 1.0? V538 Aurigae doesn't meet the former value (B-V of 0.84), so should be removed if that's what we're using; if it is the latter range, then Alpha Centauri B should also be added to the list. Titanium Dragon (talk) 00:04, 11 August 2017 (UTC)[reply]

Article should stress that there are many stars similar to our Sun[edit]

I was amazed to discover that a friend of mine thinks that even though there are a lot of stars in the universe, our Sun is very unique and significantly different than all the rest of the stars. In times where flat Earthers are abound, I think this article should stress the point that our Sun is not unique and that there are literally millions of stars similar to it in the Milky Way, not to mention in the universe. It seems that this article kinda assumes that understanding and focuses on the differences rather on the fact that, although there's no "perfect match", the examples given in the table are in fact incredibly similar to our Sun יוני לבני (talk) 01:33, 15 February 2021 (UTC)[reply]

HD 162826[edit]

No mention of HD 162826, which is — as far as I know — the only widely accepted solar sibling. — al-Shimoni (talk) 22:52, 10 January 2023 (UTC)[reply]

Orange cells in tables?[edit]

In the tables in this article, numerous cells have a light orange background color but there is no apparent legend in any of these tables as to why these cells have that background color. Below each table, there should be a note indicating what the orange color means. Vincent Ree (talk) 00:58, 10 May 2023 (UTC)[reply]

Metallicity[edit]

Why isn't the metallicity of Alpha Centauri B listed on the chart? 174.103.211.189 (talk) 01:24, 22 December 2023 (UTC)[reply]

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