Misplaced Pages

NGC 1624-2

NGC 1624-2 is the brightest star at the centre of NGC 1624 on the left of this image spanning about one degree.
Observation data Epoch J2000      Equinox J2000
Constellation	Perseus
Right ascension	04 40 37.276
Declination	50° 27′ 41.04″
Apparent magnitude (V)	11.57
Characteristics
Evolutionary stage	O-type star
Spectral type	O7f?cp
U−B color index	−0.57
B−V color index	0.9
Astrometry
Proper motion (μ)	RA: 0.025 mas/yr Dec.: 0.108 mas/yr
Parallax (π)	−0.3521 ± 0.1716 mas
Distance	5,152.3 pc
Details
Mass	34 M☉
Radius	10 R☉
Luminosity	126,000 L☉
Surface gravity (log g)	3.55 cgs
Temperature	35,000 K
Metallicity	+0.07 dex
Rotation	315.98 d
Rotational velocity (v sin i)	<3 km/s
Other designations
TYC 3350-255-1, ALS 18660, 2MASS J04403728+5027410
Database references
SIMBAD	data

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.

Properties

NGC 1624-2 is a very massive, young, blue star no more than 4 million years old. It is an Of?p star a type of highly magnetic star that has unusual emission lines of multiply-ionized carbon and nitrogen. In NGC 1624-2, the carbon emission is particularly extreme. The luminosity class is uncertain because of the unusual spectrum; it is most commonly given as V (main sequence), but has also been given as I (supergiant).

Analysis of its spectral energy distribution with CHORIZOS modelling yields an effective temperature of 35,000 K, a luminosity of 125,900 L_☉ (10 L_☉) and a radius of about 10 R_☉. Assuming a log g of 4.0 yields a mass of 34 M_☉, but evolutionary models tend towards a current mass of 28 M_☉, given the results from the modelling. However, this assumes that NGC 1624-2 is a normal star, while it is not, so it should only be taken as an indication of its true mass. NGC 1624-2 is currently losing mass at a rate of 10 M_☉/year, through a stellar wind with a terminal velocity of 2,875 km/s.

Rotation

NGC 1624-2 rotates very slowly, only once every 316 days. This slow rotation is typical for very magnetic O-type stars as their magnetic fields slow down their rotation in a process known as magnetic braking, where angular momentum is quickly shed by the stellar wind via the strong magnetic field, which also minimises mass loss throughout the main sequence.

References

1. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
2. ^ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000-03-01). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27 – L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
3. Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; Gamen, R. C.; Arias, J. I.; Alfaro, E. J. (2014-03-01). "The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars". The Astrophysical Journal Supplement Series. 211 (1): 10. arXiv:1312.6222. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10. ISSN 0067-0049. S2CID 118847528.
4. Reed, B. Cameron (2003-05-01). "Catalog of Galactic OB Stars". The Astronomical Journal. 125 (5): 2531–2533. Bibcode:2003AJ....125.2531R. doi:10.1086/374771. ISSN 0004-6256. S2CID 121285799.
5. ^ Wade, G. A.; Maíz Apellániz, J.; Martins, F.; Petit, V.; Grunhut, J.; Walborn, N. R.; Barbá, R. H.; Gagné, M.; García-Melendo, E.; Jose, J.; Moffat, A. F. J.; Nazé, Y.; Neiner, C.; Pellerin, A.; Penadés Ordaz, M. (2012-09-01). "NGC 1624-2: a slowly rotating, X-ray luminous Of?cp star with an extraordinarily strong magnetic field". Monthly Notices of the Royal Astronomical Society. 425 (2): 1278–1293. arXiv:1206.2834. Bibcode:2012MNRAS.425.1278W. doi:10.1111/j.1365-2966.2012.21523.x. ISSN 0035-8711. S2CID 53360606.
6. ^ David-Uraz, A.; Petit, V.; Shultz, M. E.; Fullerton, A. W.; Erba, C.; Keszthelyi, Z.; Seadrow, S.; Wade, G. A. (2021-02-01). "New observations of NGC 1624-2 reveal a complex magnetospheric structure and underlying surface magnetic geometry". Monthly Notices of the Royal Astronomical Society. 501 (2): 2677–2687. arXiv:2010.07482. Bibcode:2021MNRAS.501.2677D. doi:10.1093/mnras/staa3768. ISSN 0035-8711.
7. Skiff, B. A (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)". VizieR On-line Data Catalog: B/Mk. Originally Published in: Lowell Observatory (October 2014). 1. Bibcode:2014yCat....1.2023S.

v t e Constellation of Perseus
List of stars in Perseus Perseus in Chinese astronomy
Stars	Bayer α (Mirfak) β (Algol) γ δ ε ζ η (Miram) θ ι κ (Misam) λ μ ν ξ (Menkib) ο (Atik) π (Gorgonea Secunda) ρ (Gorgonea Tertia) σ τ φ ψ ω (Gorgonea Quarta) b Flamsteed 1 2 3 4 (g) 5 7 8 9 (i) 10 11 12 14 16 17 20 21 24 29 30 31 32 (l) 34 36 40 (o) 42 (n) 43 (A) 48 (c) 49 50 52 (f) 53 (d) 54 55 56 57 (m) 58 (e) 59 1 Aur Variable S T U V X Z RS RT RV RW RY ST SU SV TZ UV UX UY VX XX XY XZ YZ AB AG AR AS AW AX BM DM DY FO GK IK IP IQ IU IW IX IZ KP KS KT KW LX V351 V356 V357 V361 V376 V380 V386 V392 V396 V400 V423 V432 V440 V459 V461 V471 V472 V473 V480 V488 V490 V492 V505 V509 V518 V520 (61 And) V521 V545 V551 V572 V573 V575 V576 V621 V718 V1024 HR 470 526 529 538 540 621 641 787 792 810 820 831 842 846 849 864 865 876 885 886 890 894 918 (k) 920 923 930 949 950 956 964 966 969 973 975 979 986 991 1001 1019 1034 1037 1041 1047 1051 1056 1059 1074 1097 1113 1127 1130 1133 1141 1160 1164 1176 1191 1197 1198 1207 1215 1226 1234 1286 1301 1330 1333 1337 1344 1371 1390 1419 1424 1482 1489 1493 1500 1514 HD 13519 14433 14434 16691 16760 17092 17245 17605 21684 22781 23301 23596 25329 26702 29587 Other BD+31 643 BD+48 740 G 38-29 G 95-57 GD 61 HAT-P-15 (Berehynia) HAT-P-29 (Muspelheim) IRAS 04296+3429 L1448-IRS2E LkHα 101 LRLL 54361 NGC 1333 13 NGC 1333 IRAS 2A NGC 1333 IRAS 4A NGC 1333 IRAS 4B NGC 1624-2 PSR B0355+54 PSR J0357+3205 WR 4
Exoplanets WASP-11b/HAT-P-10b
Star clusters	NGC 869 (h) 884 (χ) 957 1039 1220 1285 1342 1444 1513 1528 1545 1624 Other Alpha Persei Cluster IC 348 Trumpler 2
Nebulae	NGC 650 (Little Dumbbell Nebula) 1333 1491 1499 (California Nebula) 1579 Other Barnard 203 Wreath Nebula
Galaxies	NGC 1003 1023 1058 1077 1086 1159 1160 1161 1167 1169 1175 (Peanut Galaxy) 1198 1250 1259 1260 1264 1265 1267 1268 1270 1271 1272 1273 1274 1275 1277 1278 1279 1281 1282 1283 1293 1294 1334 Other 1H 0323+342 IC 310 NRAO 140 UGC 2885 (Godzilla galaxy) 4C +37.11
Galaxy clusters Perseus Cluster
Astronomical events SN 2006gy Perseids
Category

• O-type main-sequence stars
• Perseus (constellation)
• 2MASS objects