NGC 7419

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NGC 7419
NGC 7419 2MASS.jpg
NGC 7419 in infrared, highlighting the five red supergiants, plus the foreground Carbon star MZ Cep at lower left
Credit: 2MASS
Observation data (J2000 epoch)
Right ascension 22h 54m 20s [1]
Declination +60° 48′ 54″ [1]
Distance 2,930+320
−260 [2] pc
Apparent magnitude  (V)13 [1]
Apparent dimensions (V)2′ [3]
Physical characteristics
Other designations Collinder 453
Associations
Constellation Cepheus
See also: Open cluster, List of open clusters

NGC 7419 is an open cluster in the constellation Cepheus. It is heavily reddened and notable for containing five red supergiants, the highest number known in any cluster until the end of the 20th century, but probably no blue supergiants.

Contents

Members

The brightest of the five red supergiants is the exceptionally cool MY Cephei. [4] It has a spectral type of M7.5 which is one of the latest spectral types of any supergiant, although analysis is made difficult by the lack of comparable standard stars. [5] It is estimated to have an effective temperature around 3,000 K [6] and a bolometric luminosity more than 100,000 L☉. [7] MY Cephei is a semiregular variable star with a brightness range of magnitude 14.4 - 15.3. [8]

The brightest hot stars in the cluster have a spectral type of BC2, indicating B2 stars with enhanced levels of carbon. [9] One has a bright giant luminosity class of II, while the other has a luminosity class of Ib-II, indicating it is either a bright giant or supergiant. The hotter stars of the cluster are visually faint due to around six magnitudes of interstellar extinction. [10]

The lack of blue supergiants, particularly in a cluster of just the right size and age to include five red supergiants, is unusual. Such low ratios of blue:red supergiants occur in low metallicity clusters, but NGC 7419 is young and has near-solar metallicity. Rapidly rotating stars may account for this evolutionary trend, encouraging high mass loss and rapid evolution of massive stars into red supergiants. This conclusion is also consistent with the high proportion of Be stars in the cluster. [4] [10]

The age of the cluster is calculated to be 14±2 million years. Clusters of this age are expected to have a main sequence turnoff at spectral type B1, and this is seen in NGC 7419. 1,200 M☉ of B-type stars alone are observed, implying a total cluster mass of 7,000 - 10,000 M☉. [10]

Non-members

Visible in the same field and as prominent as the red supergiants in infrared images is the carbon star MZ Cephei, which is much closer to us than NGC 7419. [4] It is a slow irregular variable star with a range of 14.7 - 15.4. [8]

The visually brightest star in the core region of the cluster is a yellow giant, placed at around 500 parsecs by Gaia astrometry. [11] The even brighter nearby star HD 216721 is also a foreground object. [4] Further out still from the centre of the cluster is the 7th magnitude eclipsing binary V453 Cephei, around 250 parsecs distant from us. [12]

See also

Related Research Articles

<span class="mw-page-title-main">Red supergiant</span> Stars with a supergiant luminosity class with a spectral type of K or M

Red supergiants (RSGs) are stars with a supergiant luminosity class of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive or luminous. Betelgeuse and Antares A are the brightest and best known red supergiants (RSGs), indeed the only first magnitude red supergiant stars.

<span class="mw-page-title-main">Mu Cephei</span> Red supergiant star in the constellation Cepheus

Mu Cephei, also known as Herschel's Garnet Star, Erakis, or HD 206936, is a red supergiant or hypergiant star in the constellation Cepheus. It appears garnet red and is located at the edge of the IC 1396 nebula. Since 1943, the spectrum of this star has served as a spectral standard by which other stars are classified.

<span class="mw-page-title-main">KY Cygni</span> Star in the constellation Cygnus

KY Cygni is a red supergiant of spectral class M3.5Ia located in the constellation Cygnus. It is approximately 5,000 light-years away.

<span class="mw-page-title-main">Phi Cassiopeiae</span> Star in the constellation Cassiopeia

Phi Cassiopeiae is a star in the constellation Cassiopeia. φ Cassiopeiae is a multiple star with a combined apparent magnitude of +4.95. The two brightest components are A and C, sometimes called φ1 and φ2 Cas. φ Cas A is an F0 bright supergiant of magnitude 4.95 and φ Cas C is a 7.08 magnitude B6 supergiant at 134".

KW Sagittarii is a red supergiant, located approximately 1,900 parsecs away from the Sun in the direction of the constellation Sagittarius. It is one of the largest-known stars. If placed at the center of the Solar System, the star's surface would engulf Mars.

<span class="mw-page-title-main">V354 Cephei</span> Star in the constellation Cepheus

V354 Cephei is a red supergiant star located within the Milky Way. It is an irregular variable located over 8,900 light-years away from the Sun. It has an estimated radius of 685 solar radii. If it were placed in the center of the Solar System, it would extend to between the orbits of Mars and Jupiter.

<span class="mw-page-title-main">Zeta Cephei</span> Star in the constellation Cepheus

Zeta Cephei is a star in the constellation of Cepheus. Zeta Cephei marks the left shoulder of Cepheus, the King of Joppa (Ethiopia). It is one of the fundamental stars of the MK spectral sequence, defined as type K1.5 Ib.

<span class="mw-page-title-main">MY Cephei</span> Star in the constellation Cepheus

MY Cephei is a red supergiant located in open cluster NGC 7419 in the constellation of Cepheus. It is a semiregular variable star with a maximum brightness of magnitude 14.4 and a minimum of magnitude 15.5.

<span class="mw-page-title-main">S Persei</span> Red supergiant or hypergiant variable star in the constellation Perseus

S Persei is a red supergiant or hypergiant located near the Double Cluster in Perseus, north of the cluster NGC 869. It is a member of the Perseus OB1 association and one of the largest known stars. If placed in the Solar System, its photosphere would engulf the orbit of Jupiter. It is also a semiregular variable, a star whose variations are less regular than those of Mira variables.

<span class="mw-page-title-main">RW Cephei</span> Star in the constellation Cepheus

RW Cephei is a K-type hypergiant variable star in the constellation Cepheus, at the edge of the Sharpless 132 H II region and close to the small open cluster Berkeley 94. It is among the largest stars known with a radius of almost 1,000 times that of the Sun (R☉), nearly as large as the orbit of Jupiter.

<span class="mw-page-title-main">RT Carinae</span> Star in the constellation Carina

RT Carinae, also known as CD-58 3538, is a variable star in the Carina Nebula in the constellation Carina. It has a mean apparent magnitude of +8.55.

<span class="mw-page-title-main">PZ Cassiopeiae</span> Star in the constellation Cassiopeia

PZ Cassiopeiae is a red supergiant star located in the Cassiopeia constellation, and a semi-regular variable star.

WR 142 is a Wolf-Rayet star in the constellation Cygnus, an extremely rare star on the WO oxygen sequence. It is a luminous and very hot star, highly evolved and close to exploding as a supernova. It is suspected to be a binary star with a companion orbiting about 1 AU away.

<span class="mw-page-title-main">EV Carinae</span> Red supergiant star in the constellation Carina

EV Carinae is a red supergiant and pulsating variable star of spectral type M4Ia in the constellation Carina. It is a semiregular variable star with its apparent magnitude varying between 7.4 and 9.0 in the visible band, making it only seen by binoculars or a telescope. Various periods have been identified, but the dominant one is around 347 days. It is an MK spectral standard star for the class M4.5Ia.

<span class="mw-page-title-main">BC Cygni</span> Star in the constellation Cygnus

BC Cygni is a red supergiant and pulsating variable star of spectral type M3.5Ia in the constellation Cygnus.

<span class="mw-page-title-main">RW Cygni</span> Star in the constellation Cygnus

RW Cygni is a semiregular variable star in the constellation Cygnus, about a degree east of 2nd magnitude γ Cygni. Its apparent magnitude varies between 8.05 and 9.70 and its spectral type between M3 and M4.

<span class="mw-page-title-main">CK Carinae</span> Red supergiant star in the constellation Carina

CK Carinae is a variable star in the constellation Carina, the keel of Argo Navis. It is a member of the star association Carina OB1-D, at a distance of around 2,300 parsecs or 7,500 light years.

<span class="mw-page-title-main">DU Crucis</span> Star in the constellation Crux

DU Crucis is a red supergiant and slow irregular variable star in the open cluster NGC 4755, which is also known as the Kappa (κ) Crucis Cluster or Jewel Box Cluster.

<span class="mw-page-title-main">Westerlund 1-243</span> Luminous blue variable star undergoing an eruptive phase in Westerlund 1

Westerlund 1-243 or Wd 1-243 is a luminous blue variable (LBV) star undergoing an eruptive phase located within the outskirts of the super star cluster Westerlund 1. Located about 13,400 ly (4,100 pc) from Earth, it has a luminosity of 0.73 million L☉ making it one of the most luminous stars known.

<span class="mw-page-title-main">WR 120</span> Binary star system in the constellation Scutum

WR 120 is a binary containing two Wolf-Rayet stars in the constellation of Scutum, around 10,000 light years away. The primary is a hydrogen-free weak-lined WN7 star, the secondary is a hydrogen-free WN3 or 4 star, and the system is a possible member of the cluster Dolidze 33. From our point of view, WR 120 is reddened by 4.82 magnitudes, and it has the variable designation of V462 Scuti.

References

  1. 1 2 3 "NGC 7419". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2018-01-03.
  2. ↑ Beasor, Emma R.; Davies, Ben; Smith, Nathan; Van Loon, Jacco Th; Gehrz, Robert D.; Figer, Donald F. (2020). "A new mass-loss rate prescription for red supergiants". Monthly Notices of the Royal Astronomical Society . 492 (4): 5994–6006. arXiv: 2001.07222 . Bibcode:2020MNRAS.492.5994B. doi:10.1093/mnras/staa255. S2CID   210839222.
  3. ↑ "SEDS Online NGC Database". Results for NGC 7419. Retrieved 2018-01-03.
  4. 1 2 3 4 Caron, Geneviève; Moffat, Anthony F. J.; St-Louis, Nicole; Wade, Gregg A.; Lester, John B. (2003). "The Lack of Blue Supergiants in NGC 7419, a Red Supergiant-rich Galactic Open Cluster with Rapidly Rotating Stars". The Astronomical Journal. 126 (3): 1415–1422. Bibcode:2003AJ....126.1415C. doi: 10.1086/377314 .
  5. ↑ Beauchamp, Alain; Moffat, Anthony F. J.; Drissen, Laurent (1994). "The galactic open cluster NGC 7419 and its five red supergiants". Astrophysical Journal Supplement Series. 93: 187. Bibcode:1994ApJS...93..187B. doi:10.1086/192051.
  6. ↑ Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv: 1905.03744 . Bibcode:2019AJ....158...20M. doi: 10.3847/1538-3881/ab1cbd . S2CID   148571616.
  7. ↑ Davies, Ben; Beasor, Emma R. (March 2020). "The 'red supergiant problem': the upper luminosity boundary of Type II supernova progenitors". MNRAS . 493 (1): 468–476. arXiv: 2001.06020 . Bibcode:2020MNRAS.493..468D. doi:10.1093/mnras/staa174. S2CID   210714093.
  8. 1 2 Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID   125853869.
  9. ↑ Walborn, N. R. (1976). "The OBN and OBC stars". Astrophysical Journal. 205: 419. Bibcode:1976ApJ...205..419W. doi:10.1086/154292.
  10. 1 2 3 Marco, A.; Negueruela, I. (2013). "NGC 7419 as a template for red supergiant clusters". Astronomy & Astrophysics. 552: A92. arXiv: 1302.5649 . Bibcode:2013A&A...552A..92M. doi:10.1051/0004-6361/201220750. S2CID   53723223.
  11. ↑ Gaia Collaboration; Brown, A. G. A.; Vallenari, A.; Prusti, T.; De Bruijne, J. H. J; Mignard, F.; Drimmel, R.; Babusiaux, C.; Bailer-Jones, C. A. L.; Bastian, U.; Biermann, M.; Evans, D. W.; Eyer, L.; Jansen, F.; Jordi, C.; Katz, D.; Klioner, S. A.; Lammers, U.; Lindegren, L.; Luri, X.; O'Mullane, W.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; Valette, V.; Van Leeuwen, F.; et al. (2016). "Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties". Astronomy & Astrophysics. 595: A2. arXiv: 1609.04172 . Bibcode:2016A&A...595A...2G. doi:10.1051/0004-6361/201629512. S2CID   1828208.
  12. ↑ van Leeuwen, Floor (13 August 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics. 474 (2): 653–664. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi: 10.1051/0004-6361:20078357 . eISSN   1432-0746. ISSN   0004-6361.


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