Sher 25

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Star in the constellation Carina

title: "Sher 25" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["ngc-3603", "carina-(constellation)", "b-type-supergiants", "luminous-blue-variables"] description: "Star in the constellation Carina" topic_path: "general/ngc-3603" source: "https://en.wikipedia.org/wiki/Sher_25" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Star in the constellation Carina ::

| name = Sher 25 | image = [[File:NGC 3603b.jpg|280px]] | caption = HST image of NGC 3603 with Sher 25 surrounded by a faint ring of nebulosity, above and slightly to the right of the main core of the cluster | epoch = J2000.0 | equino = J2000.0 | constell = Carina | pronounce = | ra = | dec = | appmag_v = 12.23 | type = Blue supergiant | class = B1Iab | appmag_1_passband = | appmag_1 = | appmag_2_passband = | appmag_2 = | appmag_3_passband = | appmag_3 = | appmag_4_passband = | appmag_4 = | appmag_5_passband = | appmag_5 = | appmag_6_passband = | appmag_6 = | appmag_7_passband = | appmag_7 = | appmag_8_passband = | appmag_8 = | r-i = | v-r = | b-v = 1.42 | u-b = 0.13 | j-h = | j-k = | variable = cLBV | radial_v = | prop_mo_ra = −5.387 | prop_mo_dec = +2.116 | parallax = 0.1560 | p_error = 0.0166 | parallax_footnote = | dist_ly = | dist_pc = | dist_footnote = | absmag_v = | source = | mass = | radius = | gravity = | luminosity = | luminosity_bolometric = | luminosity_visual = | temperature = | metal = | rotation = | rotational_velocity = | age_myr = | names = Sher 25, NGC 3603-25, NGC 3603 MTT 13, NGC 3603 MDS 5 | Simbad = Sher+25

Sher 25 is a blue supergiant star in the constellation Carina. It is a spectral type B1Iab star with an apparent magnitude of 12.2.{{cite journal | author=Brandner, Wolfgang| author2=Grebel, Eva K.| author3=Chu, You-Hua| author4=Weis, Kerstin | title=Ring Nebula and Bipolar Outflows Associated with the B1.5 Supergiant Sher 25 in NGC 3603 | journal=Astrophysical Journal Letters | volume=475 | page=L45 |date=January 1997 | issue=1| doi=10.1086/310460 | bibcode=1997ApJ...475L..45B |arxiv = astro-ph/9611046 | s2cid=18830644}} The star lies close to the H II region NGC 3603 of the Milky Way, but is a foreground star.

The name derives from the original cataloguing of stars in NGC 3603 by David Sher. This catalogue entry is more fully referred to as NGC 3603 Sher 25 to distinguish it from stars potentially numbered 25 by Sher in other clusters (eg. NGC 3766). The same star was numbered 13 by Melnick, Tapia, and Terlevich (MTT 13) and 5 in a Hubble Space Telescope survey by Moffat, Drissen, and Shara (NGC 3603 MDS 5).

Sher 25 has long being thought to be a member of NGC 3603, but calculations based on spectroscopy give a closer distance: 5440 pc versus 6250 pc for NGC 3603. Furthermore, its hourglass-shaped nebula does not seem to be affected by the stellar winds of OB stars in the cluster, ruling out membership to NGC 3603.

It is speculated that Sher 25 is near the point of exploding as a supernova, as it has recently thrown off matter in a pattern similar to that of supernova 1987A in the Large Magellanic Cloud, with a circumstellar ring and bipolar outflow filaments.

Regular variations in the doppler shift of the star's spectral lines with a period of a few days may be due to orbital motion about a companion star, or to pulsations of the star's surface.

References

References

  1. {{cite constellation. Sher 25
  2. (2008). "The Massive Star Content of Ngc 3603". The Astronomical Journal.
  3. (2002). "The evolutionary stat9us of Sher 25 - implications for blue supergiants and the progenitor of SN 1987A". Astronomy and Astrophysics.
  4. {{cite Gaia DR3. 5337418397799185536
  5. Weßmayer, D.. (2023-09-01). "The blue supergiant Sher 25 revisited in the Gaia era". Astronomy and Astrophysics.
  6. (2008). "The blue supergiant Sher 25 and its intriguing hourglass nebula". Monthly Notices of the Royal Astronomical Society.
  7. (1965). "Distances of five open cluster near Eta Carinae". Monthly Notices of the Royal Astronomical Society.
  8. (1989). "The galactic giant H II region NGC 3603". Astronomy and Astrophysics.
  9. (1994). "NGC 3603 and its Wolf-Rayet stars: Galactic clone of R136 at the core of 30 Doradus, but without the massive surrounding cluster halo". The Astrophysical Journal.
  10. (2014). "Sher 25: pulsating but apparently alone". Monthly Notices of the Royal Astronomical Society.

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ngc-3603carina-(constellation)b-type-supergiantsluminous-blue-variables