HD 54879

Last updated

HD 54879
Canis Major constellation map.svg
Red circle.svg
Location of HD 54879 (circled)
Observation data
Epoch J2000.0 [1]        Equinox J2000.0 [1]
Constellation Canis Major
Right ascension 07h 10m 08.14876s
Declination −11° 48′ 09.8389″
Apparent magnitude  (V)7.65 [2]
Characteristics
Evolutionary stage O9.7V [3]
U−B color index −0.80 [2]
B−V color index −0.05 [2]
J−H color index −0.037 [2]
J−K color index −0.079 [2]
Astrometry
Radial velocity (Rv)34.46±0.27 [4]  km/s
Proper motion (μ)RA: −2.808 [1]   mas/yr
Dec.: 1.270 [1]   mas/yr
Parallax (π)0.799 ± 0.0347  mas [1]
Distance 4,100 ± 200  ly
(1,250 ± 50  pc)
Details [5]
Mass 14±7  M☉
Radius 6.1±1.5  R☉
Luminosity 28200+16500
−10400  L☉
Surface gravity (log g)4.0±0.1  cgs
Temperature 30500±500  K
Rotation 2562+63
−58 d [6]
Age 5±1  Myr
Other designations
BD−11° 1822, Gaia DR2  3045391130111207808, HD  54879, HIP  34612, SAO  152491, PPM  218262, TIC  177860391, TYC  5402-632-1, GSC  05402-00632, 2MASS J07100815-1148097 [2]
Database references
SIMBAD data

HD 54879 is a bluish-hued star in the southern constellation of Canis Major, close to the border with Monoceros. It is too faint to be seen by the naked eye, having an apparent magnitude of 7.65, but can be readily observed using a pair of binoculars. [7] The star is located some 4,100 light-years (1,300  pc ) distant according to Gaia EDR3 parallax measurements, and is moving away from the Solar System at a heliocentric radial velocity of 34.46  km/s .

Contents

Stellar properties

This is an O-type main-sequence star with a stellar classification of O9.7V, indicating that it is near the border between the spectral types O and B. It radiates 28,200 times the luminosity of the Sun from its photosphere at an effective temperature of 30,500 K (30,200 °C; 54,400 °F), over five times hotter than the Sun. Its mass and radius are not well-constrained due to uncertainties in the star's distance, but simulations show that it likely formed with a mass of 16 ± 1 M☉ about 5 million years ago. [5]

Magnetic field

The star was found to have a strong magnetic field in 2014 [8] with an average strength of 2,954 G and a dipole strength of 3,939 G, [6] thousands of times stronger than Earth's magnetic field (0.25–0.65 G [9] ). Its strength slowly varies with a period of 7.41 years. [10] This is related to the extremely slow rotation of HD 54879 [11] with a period of 7.02 years, the second longest recorded in an O-type star after HD 108. [6]

Since the magnetic fields trap stellar winds to an Alfvén radius of ≳12 times the stellar radius, HD 54879 experiences very little mass loss, estimated at 6.3×10−11M☉/yr, compared to the ~1×10−9M☉/yr if the star did not possess a magnetic field. [5] The entrapped gas forms a disk around the star in the equatorial plane of the magnetic field, which is probably the source of the Hα emissions seen in the star's spectra. [10]

Element distribution

In 2021, a spectroscopic study proposed the possibility that the stellar atmosphere was inhomogeneous in elemental makeup, with helium lines forming at much higher altitudes than the emission lines of oxygen and silicon. [3] This, however, was refuted in 2024, and a more uniform chemical composition is now favored. [6]

2019 controversy

In 2019, a research team announced that a sudden spike occurred in the strength of the magnetic field, the spectral type of the star shifted from O9.7V to B2V, and that the star displays radial velocity variations indicative of a long-period binary. [12] These findings were later retracted, the apparent changes attributed to an inadequate signal-to-noise ratio related to instabilities in the data reduction pipelines. [13] However, a follow-up study by another team was unable to confirm such instabilities and instead accredited the faulty results to human error. [14]

See also

Related Research Articles

<span class="mw-page-title-main">HD 125823</span> Star in the constellation Centaurus

HD 125823, also known as V761 Centauri or a Centauri, is a variable star in the constellation Centaurus. It is a blue-white star that is visible to the naked eye with a mean apparent visual magnitude of +4.41. The distance to this star is approximately 460 light years based on parallax measurements. It is a member of the Upper Centaurus–Lupus subgroup of the Scorpius–Centaurus association.

<span class="mw-page-title-main">Przybylski's Star</span> Star in the constellation Centaurus

Przybylski's Star, or HD 101065, is a rapidly oscillating Ap star at roughly 356 light-years from the Sun in the southern constellation of Centaurus. It has a unique spectrum showing over-abundances of most rare-earth elements, including some short-lived radioactive isotopes, but under-abundances of more common elements such as iron.

HD 85725, also known as HR 3916, is a yellow hued star located in the southern constellation Antlia. It has an apparent magnitude of 6.29, placing it near the limit for naked eye visibility. The object is relatively close at a distance of 176 light-years, but is receding with a heliocentric radial velocity of 61.6 km/s.

46 Aquilae is a star in the constellation of Aquila, located to the north of Tarazed. 46 Aquilae is its Flamsteed designation. It is a dim, blue-white hued star that is a challenge to view with the naked eye, having an apparent visual magnitude of 6.33. This object is located approximately 830 light years from the Sun, based on parallax. It is moving closer to the Earth with a heliocentric radial velocity of −25 km/s.

<span class="mw-page-title-main">Rho Ophiuchi</span> Multiple star system in the constellation Ophiuchus

Rho Ophiuchi is a multiple star system in the constellation Ophiuchus. The central system has an apparent magnitude of 4.63. Based on the central system's parallax of 9.03 mas, it is located about 360 light-years away. The other stars in the system are slightly farther away.

Zeta Circini, Latinized from ζ Circini, is the Bayer designation for a star located in the southern constellation of Circinus. With an apparent visual magnitude of 6.08, it is barely visible to the naked eye on a dark night. The distance to this star, as estimated using an annual parallax shift of 2.56 mas, is around 1,300 light years.

<span class="mw-page-title-main">N Scorpii</span> Star in the constellation of Scorpius

N Scorpii, also known as HD 148703, is a solitary, bluish-white hued star located in the southern constellation Scorpius. It has an apparent magnitude of 4.23, making it readily visible to the naked eye. N Scorpii was initially given the Bayer designation Alpha Normae by Lacaille but it was later moved from Norma to Scorpius. N Scorpii is currently located 550 light years away based on parallax measurements from the Hipparcos satellite and is part of the Upper Scorpius–Centaurus region of the Scorpius–Centaurus association.

HD 98176, also designated as HIP 55133 and rarely 22 G. Centauri, is a solitary, white hued star located in the southern constellation Centaurus. It has an apparent magnitude of 6.44, placing it near the limit for naked eye visibility. Based on parallax measurements from Gaia DR3, the object is estimated to be 348 light years distant. At its current distance, its brightness is diminished by 0.32 magnitudes due to interstellar dust. Pauzen et al. (2001) lists it as a potential λ Boötis star.

HD 175640 is a star in the equatorial constellation of Aquila. It has an apparent visual magnitude of 6.20, which is bright enough to be visible to the naked eye under suitable seeing conditions. The star is located at a distance of approximately 516 light years as determined through parallax measurements. At that distance, the star's color is modified by an extinction of 0.36 magnitude due to interstellar dust. It is drifting closer with a heliocentric radial velocity of roughly −26 km/s.

Theta Hydri, Latinized from θ Hydri, is a blue-white hued star in the southern constellation of Hydrus. It is faintly visible to the naked eye with an apparent visual magnitude of +5.53. Based upon an annual parallax shift of 6.50 mas as seen from Earth, it is located approximately 502 light years. At that distance, the visual magnitude of the star is diminished by an extinction of 0.10 due to interstellar dust. It is moving away from the Sun with a radial velocity of +12.3 km/s.

<span class="mw-page-title-main">AK Scorpii</span> Binary star in the constellation Scorpius

AK Scorpii is a Herbig Ae/Be star and spectroscopic binary star about 459 light-years distant in the constellation Scorpius. The star belongs to the nearby Upper Centaurus–Lupus star-forming region and the star is actively accreting material. The binary is surrounded by a circumbinary disk that was imaged with VLT/SPHERE in scattered light and with ALMA.

<span class="mw-page-title-main">KQ Velorum</span> Binary star system in the constellation Vela

KQ Velorum is a variable star system in the southern constellation of Vela. It has the identifier HD 94660 in the Henry Draper Catalogue; KQ Vel is the variable star designation. This appears as a sixth magnitude star with an apparent visual magnitude of 6.112, and thus is dimly visible to the naked eye under suitable viewing conditions. The system is located at a distance of approximately 373 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of around 23 km/s.

HD 89571 is a binary star located in the northern circumpolar constellation Camelopardalis. It is faintly visible to the naked eye with a combined apparent magnitude of 5.51 and is estimated to be 142 light years away from the Solar System. However, it is receding with a heliocentric radial velocity of 3.5 km/s.

HD 34255, also known HR 1720, is a star located in the northern circumpolar constellation Camelopardalis, the giraffe. It has an apparent magnitude of 5.60, allowing it to be faintly visible to the naked eye. The object is located relatively far at a distance of about 1.65 kly but is approaching the Solar System with a heliocentric radial velocity of −7.7 km/s.

<span class="mw-page-title-main">HD 22764</span> Double star; Camelopardalis

HD 22764, also known as HR 1112, is an orange hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.78, allowing it to be faintly visible to the naked eye. The object is located relatively far at a distance of approximately 1,770 light years based on Gaia DR3 parallax measurements but is approaching the Solar System with a heliocentric radial velocity of −12.5 km/s. At its current distance, HD 22764's brightness is diminished by 0.66 magnitudes due to interstellar dust.

<span class="mw-page-title-main">V686 Coronae Australis</span> Alpha2 CVn variable; Corona Australis

V686 Coronae Australis is a solitary, bluish-white-hued variable star located in the southern constellation Corona Australis. It has an apparent magnitude that ranges between 5.25 and 5.41, which makes it faintly visible to the naked eye. Gaia DR3 parallax measurements imply a distance of 480 light years and it is slowly receding with a heliocentric radial velocity of 1.3 km/s. At its current distance V686 CrA's average brightness is diminished by 0.35 magnitudes due to extinction from interstellar dust and it has an absolute visual magnitude of −0.24.

<span class="mw-page-title-main">HD 177765</span> Star in the constellation Sagittarius

HD 177765 is a white-hued star in the southern constellation of Sagittarius. With an apparent magnitude of 9.15, it is too faint to be seen by the naked eye from Earth, but is dimly visible using binoculars. It is located at a distance of 1,284 light-years according to Gaia EDR3 parallax measurements.

<span class="mw-page-title-main">HD 166473</span> Star in the constellation Corona Australis

HD 166473 is a rapidly oscillating Ap star and an α2 CVn variable located about 455 light-years away in the southern constellation of Corona Australis. It has the variable star designation V694 Coronae Australis. With an apparent magnitude of 7.953, it is too faint to be seen by the naked eye from Earth, but can be observed using binoculars.

<span class="mw-page-title-main">HD 194783</span> HgMn star; Microscopium

HD 194783 is a solitary star located in the southern constellation Microscopium near the border with Sagittarius. It is barely visible to the naked eye as a bluish-white-hued point of light with an apparent magnitude of 6.08. The object is located relatively far at a distance of 740 light-years based on Gaia DR3 parallax measurements, but it is drifting closer with a heliocentric radial velocity of −9.7 km/s. At its current distance, HD 194783's brightness is diminished by an interstellar extinction of 0.31 magnitudes and it has an absolute magnitude of either −0.59 or −1.10, depending on the source.

<span class="mw-page-title-main">HD 9289</span> Star in the constellation Cetus

HD 9289 is a white-hued variable star in the constellation of Cetus. It has the variable-star designation BW Ceti. With an apparent magnitude of 9.38, it is too faint to be observed by the naked eye from Earth. It is located at a distance of approximately 1,000 light-years according to Gaia EDR3 parallax measurements, and is moving away from the Solar System at a heliocentric radial velocity of 11.352 km/s.

References

  1. 1 2 3 4 5 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  2. 1 2 3 4 5 6 "HD 54879". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2 November 2024.
  3. 1 2 Järvinen, S P; Hubrig, S; Schöller, M; et al. (23 December 2021). "Detection of anomalous element distribution in the extremely slowly rotating magnetic O9.7 V star HD 54879". Monthly Notices of the Royal Astronomical Society. 510 (3). Oxford University Press (OUP): 4405–4419. arXiv: 2112.14362 . doi: 10.1093/mnras/stab3720 . ISSN   0035-8711.
  4. ↑ Boyajian, T. S.; Gies, D. R.; Baines, E. K.; et al. (2007). "Radial Velocities of Six OB Stars". Publications of the Astronomical Society of the Pacific. 119 (857). IOP Publishing: 742–746. arXiv: 0706.1221 . Bibcode:2007PASP..119..742B. doi: 10.1086/520707 . ISSN   0004-6280.
  5. 1 2 3 Shenar, T.; Oskinova, L. M.; Järvinen, S. P.; et al. (2017). "A combined HST and XMM-Newton campaign for the magnetic O9.7 V star HD 54879". Astronomy & Astrophysics. 606. EDP Sciences: A91. arXiv: 1708.01261 . doi: 10.1051/0004-6361/201731291 . ISSN   0004-6361.
  6. 1 2 3 4 Erba, C.; Folsom, C. P.; David-Uraz, A.; Wade, G. A.; Seadrow, S.; Bellotti, S.; Fossati, L.; Petit, V.; Shultz, M. E. (2024). "First Observation of the Complete Rotation Period of the Ultra-Slowly Rotating Magnetic O Star HD 54879". The Astrophysical Journal. 977 (1): 84. arXiv: 2401.09722 . Bibcode:2024ApJ...977...84E. doi: 10.3847/1538-4357/ad865a .
  7. ↑ Zarenski, Ed (2004). "Limiting Magnitude in Binoculars" (PDF). Cloudy Nights. Archived (PDF) from the original on 21 July 2011. Retrieved 6 May 2011.
  8. ↑ Castro, N.; Fossati, L.; Hubrig, S.; et al. (10 July 2015). "B fields in OB stars (BOB). Detection of a strong magnetic field in the non-peculiar O9.7V star HD 54879". Astronomy & Astrophysics. EDP Sciences. arXiv: 1507.03591 . doi: 10.1051/0004-6361/201425354 . ISSN   0004-6361.
  9. ↑ Finlay, C. C.; Maus, S.; Beggan, C. D.; et al. (December 2010). "International Geomagnetic Reference Field: the eleventh generation". Geophysical Journal International. 183 (3): 1216–1230. Bibcode:2010GeoJI.183.1216F. doi: 10.1111/j.1365-246X.2010.04804.x . hdl: 20.500.11850/27303 .
  10. 1 2 Küker, Manfred; Järvinen, Silva; Hubrig, Swetlana; Ilyin, Ilya; Schöller, Markus (2024). "Characterizing the dynamical magnetosphere of the extremely slowly rotating magnetic O9.7 V star HD 54879 using rotational modulation of the H $α$ profile". Astronomische Nachrichten. 345 (4). arXiv: 2402.11244 . Bibcode:2024AN....34530169K. doi:10.1002/asna.20230169.
  11. ↑ Hubrig, S; Järvinen, S P; Schöller, M; et al. (31 October 2019). "The very slow rotation of the magnetic O9.7 V star HD 54879". Monthly Notices of the Royal Astronomical Society. 491 (1). Oxford University Press (OUP): 281–288. arXiv: 1910.13209 . doi: 10.1093/mnras/stz3046 . ISSN   0035-8711.
  12. ↑ Hubrig, S; Küker, M; Järvinen, S P; et al. (18 January 2019). "A short and sudden increase of the magnetic field strength and the accompanying spectral variability in the O9.7 V star HD 54879". Monthly Notices of the Royal Astronomical Society. 484 (4). Oxford University Press (OUP): 4495–4506. arXiv: 1901.03975 . doi: 10.1093/mnras/stz198 . ISSN   0035-8711.
  13. ↑ Hubrig, S; Küker, M; Järvinen, S P; Kholtygin, A F; Schöller, M; Ryspaeva, E B; Sokoloff, D D (5 November 2019). "Erratum: A short and sudden increase of the magnetic field strength and the accompanying spectral variability in the O9.7 V star HD 54879". Monthly Notices of the Royal Astronomical Society. 490 (4). Oxford University Press (OUP): 5691. doi: 10.1093/mnras/stz3095 . ISSN   0035-8711.
  14. ↑ Wade, G A; Bagnulo, S; Keszthelyi, Z; et al. (20 November 2019). "No evidence of a sudden change of spectral appearance or magnetic field strength of the O9.7V star HD 54879". Monthly Notices of the Royal Astronomical Society: Letters. 492 (1). Oxford University Press (OUP): L1 –L5. arXiv: 1910.14495 . doi: 10.1093/mnrasl/slz174 . ISSN   1745-3925.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.