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

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Scutum is a small constellation. Its name is Latin for shield, and it was originally named Scutum Sobiescianum by Johannes Hevelius in 1684. Located just south of the celestial equator, its four brightest stars form a narrow diamond shape. It is one of the 88 IAU designated constellations defined in 1922.

<span class="mw-page-title-main">Supergiant</span> Type of star that is massive and luminous

Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8. The temperature range of supergiant stars spans from about 3,400 K to over 20,000 K.

<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 and a stellar classification 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">Phi Cassiopeiae</span> Star in the constellation Cassiopeia

Phi Cassiopeiae is a multiple star in the constellation Cassiopeia 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 star, located approximately 2,160 parsecs away from the Sun in the direction of the constellation Sagittarius. It is one of the largest known stars, with a diameter about 1,000 times larger than the Sun. If placed at the center of the Solar System, the star's surface would engulf Mars, coming close to Jupiter's orbit.

V354 Cephei is a red supergiant star located within the Milky Way. It is an irregular variable located over 13,000 light-years away from the Sun. It has an estimated radius of 1,139 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">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> Hypergiant star in the constellation Cepheus

RW Cephei is a K-type hypergiant and a semirregular 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">S Monocerotis</span> Star in the constellation Monoceros

S Monocerotis, also known as 15 Monocerotis, is a massive multiple and variable star system located in the constellation Monoceros. It is the brightest star in the Christmas Tree open cluster in the area catalogued as NGC 2264.

<span class="mw-page-title-main">WOH G64</span> Red supergiant in the constellation Dorado

WOH G64 is an unusual red supergiant (RSG) star in the Large Magellanic Cloud (LMC) satellite galaxy in the southern constellation of Dorado. It is one of the largest known stars, being described as possibly being the largest star known. It is also one of the most luminous and massive red supergiants, with a radius calculated to be around 1,540 times that of the Sun (R☉) and a luminosity around 282,000 times the solar luminosity (L☉).

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

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

<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">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">Stephenson 2 DFK 1</span> Star in the open cluster Stephenson 2

Stephenson 2 DFK 1, also known as RSGC2-01 or Stephenson 2-18, is a red supergiant (RSG) or possible extreme red hypergiant (RHG) star in the constellation of Scutum. It lies near the open cluster Stephenson 2, which is located about 5.8 kiloparsecs away from Earth in the Scutum–Centaurus Arm of the Milky Way galaxy, and is assumed to be one of a group of stars at a similar distance, although some studies consider it to be an unrelated or foreground red supergiant.

<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">NGC 1624-2</span> Star in the constellation Perseus

NGC 1624-2 is a massive O-type star located in the star cluster NGC 1624, in the constellation of Perseus, about 16,800 light years away. NGC 1624-2 is notable for being most strongly magnetised O-type star known, with a magnetic field strength of 20 kG, or about 20,000 times the Sun's magnetic field strength. It hosts a large and dense magnetosphere, formed from the interaction between its very strong magnetic field and its dense, radiatively-driven stellar wind, which also absorbs up to 95% of x-rays generated from around the star.

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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