|WikiProject Astronomy / Astronomical objects||(Rated B-class, Mid-importance)|
||It is requested that an image or photograph of the planetary system and their orbits be included in this article to improve its quality.
The Free Image Search Tool may be able to locate suitable images on Flickr and other web sites.
Orbit of PSR 1257+12 comet
Does anyone have data on the orbit of the tiny object orbiting PSR 1257+12? The 40 AU/170 year orbit was for the disproven gas giant planet. --Jyril 21:11, Mar 2, 2005 (UTC)
- orbit: 6x further out than planet C ; mass: 0.04 MEarth's Moon ; 220.127.116.11 20:07, 21 Apr 2005 (UTC)
- I don't think we know the mass and the distance of the pulsar to the precision implied by the numbers. And the mass seems to be too low because it should be a white dwarf at about 0.3 MSun. 18.104.22.168 1 July 2005 11:14 (UTC)
- Quick calculation using the orbital periods and distances of the planets gives a mass of about 0.7 times solar, so the value given is clearly wrong.--Jyril July 1, 2005 12:48 (UTC)
- The closest thing I've found is the parameters for the object just before the gravitational perturbation hypothesis was disproved, see Arecibo Newsletter #33 (pdf). The parameters given are period ~3.5 years, semimajor axis ~2.6 AU, eccentricity >0.5. Presumably since the cause of the periodicity is non-gravitational, the eccentricity value is spurious, however the period should presumably still be valid. 2.6 AU fits with "approximately six times larger than that of the third planet in the system", so I'm going to go with that for the moment. Chaos syndrome 16:44, 24 July 2006 (UTC)
- Planets of PSR 1257+12 follow different naming scheme. They were designated A, B, and C before the discovery of 51 Pegasi b and other planets around main sequence stars (which introduced the naming system b, c, d...). See for example this pdf file, 6th page or this page. Extrasolar Planets Encyclopaedia listed the planets in similar way, but after it started to use php, automatical script changed them to b, c, and d (which is wrong).--Jyril 17:52, 6 January 2006 (UTC)
- Perhaps it might be a good idea to add something in the article about the nonstandard naming system to avoid confusion. Chaos syndrome 16:06, 8 January 2006 (UTC)
- If you notice the other pulsar planet, Methuselah, PSR B1620-26 c isn't named exactly like other exoplanets either. (PSR B1620-26b is a star, and it's not PSR B1620-26 B either). Zzzzzzzzzzz 03:57, 25 January 2006 (UTC)
- I'd rather follow the designation style used in published papers, instead of any web pages. As I wrote earlier, the Extrasolar Planets Encyclopaedia used uppercase letters before moving to a PHP system. More importantly, Wolszczan himself uses uppercase letters. The situation is similar with OGLE-2005-BLG-390Lb, where the discoverers use a designation without spaces (I preferred a space before 'b'). I think it's fair to say their opinion is the final one. But if you want to change the letters to lowercase, I recommend you start a voting before renaming them.--Jyril 12:51, 16 February 2006 (UTC)
In a recent change, we now have a whole bunch of claims that the planets have been renamed. Are there any sources for this, or do we revert the designations back to A,B,C? Chaos syndrome 20:41, 28 August 2006 (UTC)
Hessman et al (2010) , pg 2 col 1, state that "the planets around the pulsar PSR 1257+12 were long labeled numerically starting with the index 1 but have also been labeled with lower-case letters starting with "a" (Currie & Hansen 2007) and upper-case letters starting with "A" (Wolszczan 2010)." Cuddlyopedia (talk) 14:22, 8 October 2011 (UTC)
Mass of PSR 1257+12
Where did this come: "It has a mass of 0.29874213836478 MSUN...". That value is way too low (and precise) for a pulsar mass. Quick calculation (m = a^3/P^2) from its planets' orbits gives a reasonable mass of ~1.4 MSun.--Jyril 11 January, 2006 21:51 (UTC)
- This was in the original write-up posted by 22.214.171.124 (talk · contribs). It is indeed bogus, as among other things the mass would have to be greater than the Chandrasekhar limit. I can't find any references to the mass online after a quick search. I've removed the mass note and other unsourced material from that section of the article until a reference can be dug up. The other material _sounded_ plausible, but it really can't be in the article until it's properly referenced. --Christopher Thomas 05:17, 27 January 2006 (UTC)
PSR 1257+12 D
Can anyone provide a reference for this designation in the scientific literature? I haven't seen it used outside of speculative sites such as Extrasolar Visions, which doesn't qualify it as a real designation. Chaos syndrome 23:02, 11 January 2006 (UTC)
- It was used in the Extrasolar Planets Encyclopedia for the spurious gas giant, but not for the asteroid. Good point, the use of this designation is probably not justified in Wikipedia.--Jyril 06:54, 12 January 2006 (UTC)
Distance to the pulsar?
- Update to the distance is based on the latest paper (Konacki & Wolszczan 2003, ApJLett, 591, L147) Aasastrohistory (talk) 14:17, 23 July 2011 (UTC)
- I just realized why the erroneous value of "980" light years was originally given. The best estimate distance is based on the dispersion measure (which has substantial uncertainty) as reported by Konacki & Wolszczan (2003, ApJLett, 591, L147) to be 0.6 kpc. When multiplied by 3.3 (the conversion factor between parsecs and lightyears to two significant digits), we get 1980. So I expect that somewhere along the line someone made a typo and dropped the "1", changing "1980" to "980". Aasastrohistory (talk) 13:29, 25 July 2011 (UTC)
April 6, 2006 cleanup
I did a massive cleanup to this artical. I did:
- Put a.k.a. to the planets because if I thoight they were called this, then possibly anyone else.
- Put starbox for pulsar to tell some info better put in the box.
- I also put an image of the planets to get better visulatation.
- Do we really need the "other resources" section? A quick check of other articles on the WikiPedia suggests that the convention is to put these as main headings without some kind of "other resources" group. Chaos syndrome 14:38, 7 April 2006 (UTC)
- I removed the header. We should follow the Wikipedia standard. Also, don't use HTML code unless really necessary. There's easy way to replace <BR> with Wikicode: just add empty lines in the edit box
- like here.--Jyril 09:38, 8 April 2006 (UTC)
What is the source for the temperatures of the planets? Chaos syndrome 22:00, 7 April 2006 (UTC)
- Where else, Extrasolar Visions! But before you go around deleting it, how can you 100% known a planets temperature unless you've been there. In short, they should still be there because an extrasolar planet's temperature can't be 100% accurate, just guessed! But it's still good to put in the best guessed answer we have to this problem. — HurricaneDevon @ 12:28, 8 April 2006 (UTC)
- Presumably the pulsar temperature is also an Extrasolar Visions value? I haven't seen a value given elsewhere. Chaos syndrome 15:19, 8 April 2006 (UTC)
- Similarly the pulsar radius? Chaos syndrome 16:05, 8 April 2006 (UTC)
- Well, I hope any "inaccurate" Extrasolar Vision values at least have an inaccuracy listed so we know if it's X degress with 10% uncertainty, or 80%. ;) Without this number, it's hard to know if it's almost a complete guess, or if it's very close according to our models. I see the numbers have since added been removed now, and I think I'd recommend that unless we have something better than a number without any certainty information. -- Northgrove 07:29, 25 April 2007 (UTC)
- The mass value for PSR B1257+12 "D" is an upper limit based on the non-detection of gravitational effects... it could easily be much smaller. I'd hold off on claiming planethood. If the object exists, it has been detected via cometary activity (the object's coma affects the transmission of the pulsar's emissions). Chaos syndrome 10:13, 19 August 2006 (UTC)
Roundness: mass atleast 5 x 1020 kg, or diameter atleast 800 km in size. 
http://exoplanet.eu/star.php?st=PSR+1257%2B12 When you go there, you will notice that it is listed as b,c,d and the A,B,C,D has been dropped, as well as the asteroid/comet 4th body. Also, the system possibly contains comet(s). Thanks, CarpD 8/28/06
- As discussed above on this talk page, the Extrasolar Planets Encyclopaedia uses an automated PHP-based approach which doesn't allow the planets to be specified as A,B,C. The designations there are in error. Chaos syndrome 18:58, 29 August 2006 (UTC)
Can we please have a reliable source for the asteroid/comet being designated D? My investigations with Google reveal only Wikipedia and the website Extrasolar Visions using "D" or "d" to refer to the asteroid/comet, and the Extrasolar Planets Encyclopaedia using "d" to refer to planet C. Chaos syndrome 19:04, 31 August 2006 (UTC)
first extrasolar planets?
The intro says the planets were the first extrasolar planets discovered. I'm almost certain that's supposed to be first solid extrasolar planets. Plethorae of gas giants were discovered first, but the one small one was the first rock ever found. Thanatosimii 21:33, 23 November 2006 (UTC)
- No. As odd as it sounds, they're the first confirmed extrasolar planets. There are some planets whose existence was suspected earlier, but they remained unconfirmed (for instance, Gamma Cephei Ab, was first detected in 1989 but not confirmed until 2002). The reason for this is that pulsars' radio pulses are tremendously accurate allowing extremely small discrepancies caused by terrestrial planets to be detected. That is not possible with radial velocity methods (except for very quiet stars with huge amount of data points).--JyriL talk 22:53, 23 November 2006 (UTC)
"Because planet B and planet C orbit rather close to each other, they cause measurable perturbations in each other's orbits. This phenomenon provides very strong evidence for the existence of both planets."
Does this need to be reworded? How can the planets orbit provide "strong evidence" of its existance? It's like saying my steering wheel provides strong evidence that I own a car or my shoes are evidence that I have feet.
- The sentence was poorly written, I rewrote it. The planets were detected by timing pulses coming from the pulsar. As the pulsar moves towards us, the frequency of the pulses rises and vice versa (see Doppler effect); the actual frequency is extremely close to a constant. In theory, some weird phenomenon could mimic the planets. However, because we can detect the perturbations caused by the planets in each other, exactly as predicted, it is next to impossible to figure out any source for changes in pulse arrival times other than planets orbiting the pulsar.--JyriL talk 12:22, 20 January 2007 (UTC)
A diagram of the planetary system, and their orbits would be nice. 126.96.36.199 22:54, 7 March 2007 (UTC)
NuclearVacuum excised this table
- Honestly, I have no idea what you are implying here. There is no need for this box simply because of the fact that it is a "suspected comet," and not a planet (in this classification). Let's keep the planets in planetboxes, and suspected comets out of them. However, I have no trouble mentioning it in the order planetbox (witch I took the liberty to add "D" to). Also, what is your definition of "excised"? — NuclearVacuum 18:08, 20 June 2008 (UTC)
- I'm using plain english. It should be clear what I am stating, since I am stating it without obfuscation. You cut out the table, you removed the table, you excised the table, you deleted the table, you erased the table, you reformatted the article to make the table disappear, you edited the article to make it appear without a table, you cleared the table from the article. Need I add more clarifying statements? 188.8.131.52 (talk) 04:57, 30 June 2008 (UTC)
The article includes a 'size comparison' of the four planets. Isn't this impossible given that we only know their masses, not their diameters? I think this should be removed.Masursky (talk) 19:12, 15 September 2008 (UTC)
- Jenny Hogan (2006). "Planets are round. Will that do?". Nature.