Talk:HD 139139

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Created talk-page[edit]

Created the talk-page for the "HD 139139" article - Enjoy! :) Drbogdan (talk) 03:25, 4 July 2019 (UTC)[reply]

Distance unclear?[edit]

@Lithopsian: Seems the EPIC 249706694 "Distance" (defined as "pc" at => http://archive.stsci.edu/k2/epic/help/columns.html#d ) - and the value given seems to be "175.500" - after adding "249706694" to the EPIC Searcher - at => http://archive.stsci.edu/k2/epic/search.php (in the EPIC field) (also another related EPIC ref)[1] - thus, "572.40 ly (175.500 pc)" away - not "350 ly (110 pc)"[2] as currently presented in the article? - in any case - Enjoy! :) Drbogdan (talk)

Yes, looks like it. The nearest neighbour distance is actually 15.1, so not that. That distance is still wrong though. I don't know where it has come from. It isn't in the original EPIC catalog (Huber+, 2017). Lithopsian (talk) 20:43, 5 July 2019 (UTC)[reply]
VizeR table entry. No distance, which is a shame because the distance code would have explained where it came from. C15 entries supposedly use Gaia DR1 parallaxes, but that is 9.25 mas, so not that. Distances can also be based on (assumed) absolute proper motions, so maybe that, or maybe just added later on a whim. Best to ignore it, multiple other sources with very small margins of error all say it is around 108 pc. Lithopsian (talk) 20:56, 5 July 2019 (UTC)[reply]

References

  1. ^ Space Telescope Science Institute (STScI) (2019). "K2 Search Results - EPIC 249706694". Space Telescope Science Institute. Retrieved 5 July 2019.
  2. ^ Starr, Michelle (2 July 2019). "Astronomers Found a Star That Dims So Erratically, They Have No Explanation For It". ScienceAlert.com. Retrieved 4 July 2019.

Location unclear?[edit]

@Lithopsian: Seems that the HD 139139 (EPIC 249706694) star location is given as 234.27559 -19.14292 by Rappaport[1] - this converts to 15h 37m 06.14s -19d 08m 34.51s using the "RA DEC flexible converter"[2] or 15h 37m 6.1416s -19° 8m 34.512s using Wikipedia converting templates - the star location is also given as 15 37 06.215 -19 08 32.96 by the Space Telescope Science Institute[3] - this can be adjusted to 15h 37m 06.215s -19d 08m 32.96s - thus - two different location settings based on two different WP:RS => 15h 37m 06.1416s -19d 08m 34.512s[1] versus 15h 37m 06.215s -19d 08m 32.96s.[3]

QUESTIONS: Is this a significant difference in star locations? Which is the better star location to use? - in any case - Enjoy! :) Drbogdan (talk) 15:20, 6 July 2019 (UTC)[reply]

The difference is significant, although not huge. It is worth adding the Gaia DR2 position, which could be considered definitive: 15h 37m 06.215s −19° 08′ 33.09″. This is only marginally different from the EPIC catalogue value, which leaves the question of why the Rappaport value is different. Most likely, their photometry is just not accurate enough. It is ground-based from various sources and aimed more at establishing the relations between the two binary components than definitive coordinates. They describe some shortcomings of their images, so not surprising that the positions of the two individual stars are slightly off. Lithopsian (talk) 12:49, 7 July 2019 (UTC)[reply]
@Lithopsian: Thanks for your comments - and suggested star coordinates (ie, 15h 37m 06.215s -19° 08′ 33.09″)[4] - updated the main "HD 139139" article accordingly - seems ok - please comment if otherwise of course - iac - Enjoy! :) Drbogdan (talk) 13:39, 7 July 2019 (UTC)[reply]

References

  1. ^ a b Rappaport, S.; Vanderburg, A.; Kristiansen, M. H.; Omohundro, M. R.; Schwengeler, H. M.; Terentev, I. A.; Dai, F.; Masuda, K.; Jacobs, T. L.; Lacourse, D.; Latham, D. W.; Bieryla, A.; Hedges, C. L.; Dittmann, J.; Barentsen, G.; Cochran, W.; Endl, M.; Jenkins, J. M.; Mann, A. (2019). "The Random Transiter – EPIC 249706694/HD 139139". Monthly Notices of the Royal Astronomical Society. arXiv:1906.11268. doi:10.1093/mnras/stz1772. – ref details at => https://arxiv.org/pdf/1906.11268.pdf
  2. ^ Skowron, Jan (2019). "RA DEC flexible converter". Warsaw University Observatory. Retrieved 6 July 2019.
  3. ^ a b Space Telescope Science Institute (STScI) (2019). "K2 Search Results - EPIC 249706694". Space Telescope Science Institute. Retrieved 6 July 2019.
  4. ^ Staff (2019). "Basic data: HD 139139 -- High proper-motion Star". SIMBAD. Retrieved 7 July 2019.

Solar System transits[edit]

Planets transiting the Sun as viewed from HD 139139 are briefly mentioned at 24:52 of The Mysterious Star HD 139139 with Dr. Andrew Vanderburg Agmartin (talk) 20:31, 9 July 2019 (UTC)[reply]