V2052 Ophiuchi

V2052 Ophiuchi, also known as HR 6684, is a star about 920 light years from Earth in the constellation Ophiuchus.^[2] It is a 5th-magnitude star, making it faintly visible to the naked eye of an observer far from city lights. V2052 Ophiuchi is a Beta Cephei variable (β Cep) star, varying slightly in brightness from magnitude 5.81 to 5.84 over a period of about 3.4 hours.^[3]

V2052 Ophiuchi

A light curve for V2052 Ophiuchi, plotted from Hipparcos data[1]
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Ophiuchus
Right ascension	17h 56m 18.40012s[2]
Declination	+00° 40′ 13.2733″[2]
Apparent magnitude (V)	5.81 – 5.84[3]
Characteristics
Spectral type	B2 IV–V[4]
U−B color index	−0.66[5]
B−V color index	+0.09[5]
Variable type	β Cephei[3]
Astrometry
Proper motion (μ)	RA: −4.997±0.038[2] mas/yr Dec.: −0.369±0.038[2] mas/yr
Parallax (π)	3.5446 ± 0.0453 mas[2]
Distance	920 ± 10 ly (282 ± 4 pc)
Absolute magnitude (MV)	−2.54[6]
Details
Mass	8.9±0.7[7] M☉
Radius	4.1±0.2[8] R☉
Luminosity	3,426[2] L☉
Surface gravity (log g)	4.00[4] cgs
Temperature	23,000±1,000[4] K
Metallicity [Fe/H]	+0.012[2] dex
Rotation	3.638833±0.000003 d[9]
Rotational velocity (v sin i)	60[9] km/s
Age	21[10] Myr
Other designations
HR 6684, HD 163472, HIP 87812, SAO 122935[11]
Database references
SIMBAD	data

In 1972, Mikolaj Jerzykiewicz announced that HR 6684 is a variable star, based on his observations using the 0.6 meter Air Force Telescope on Mauna Kea. He classified the star as a β Cep variable with period of 0.13989 days, He further noted that if confirmed, it would be the least luminous and shortest period β Cep star known up to that date.^[12] Spectroscopic and photometric observations by D. Harold McNamara and Bruce Bills in 1973 confirmed Jerzykiewicz's results.^[13] In 1973, HR 6684 was given the variable star designation V2052 Ophiuchi.^[14]

In 1994, Henryk Cugier et al. determined that V2052 Ophiuchi pulsated primarily in the fundamental (l=0) radial mode.^[15] A much less powerful non-radial pulsation mode was identified in 2003.^[8] Ultraviolet observations by the TD-1A satellite show that throughout its pulsation cycle, the temperature of V2052 Ophiuchi varies by 1040±880 K, and its radius changes by 3.1%±0.9%.^[5] Observations at the Pic du Midi Observatory showed that V2052 Ophiuchi has a dipole magnetic field, the axis of which is offset from the star's center, and there are helium spots on the surface near the magnetic poles.^[9] V2052 Ophiuchi is a type of chemically peculiar star known as a helium-strong star. Its surface is over-abundant in helium, and under-abundant in oxygen, perhaps due to its magnetic field differentially effecting the diffusion of elements in its atmosphere.^[8]

References

1. EAS (1997). "The HIPPARCOS and TYCHO catalogues". Astrometric and Photometric Star Catalogues Derived from the ESA Hipparcos Space Astrometry Mission. ESA SP Series. 1200. Noordwijk, Netherlands: ESA Publications Division. Bibcode:1997ESASP1200.....E. ISBN 9290923997. Retrieved 15 October 2022.
2. 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.
3. 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. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
4. Morel, T.; Butler, K.; Aerts, C.; Neiner, C.; Briquet, M. (October 2006). "Abundance analysis of prime B-type targets for asteroseismology. I. Nitrogen excess in slowly-rotating β Cephei stars". Astronomy and Astrophysics. 457 (2): 651–663. arXiv:astro-ph/0607264. Bibcode:2006A&A...457..651M. doi:10.1051/0004-6361:20065171.
5. Beeckmans, F.; Burger, M. (December 1977). "Ultraviolet observations of beta Canis Majoris stars with the TD-1 A satellite". Astronomy and Astrophysics. 61: 815–826. Bibcode:1977A&A....61..815B.
6. Melnik, A. M.; Dambis, A. K. (2020). "Distance scale for high-luminosity stars in OB associations and in field with Gaia DR2. Spurious systematic motions". Astrophysics and Space Science. 365 (7): 112. arXiv:2006.14649. Bibcode:2020Ap&SS.365..112M. doi:10.1007/s10509-020-03827-0. S2CID 220128144.
7. Briquet, M.; Neiner, C.; Aerts, C.; Morel, T.; Mathis, S.; Reese, D. R.; Lehmann, H.; Costero, R.; Echevarria, J.; Handler, G.; Kambe, E.; Hirata, R.; Masuda, S.; Wright, D.; Yang, S.; Pintado, O.; Mkrtichian, D.; Lee, B. C.; Han, I.; Bruch, A.; De Cat, P.; Uytterhoeven, K.; Lefever, K.; Vanautgaerden, J.; de Batz, B.; Frémat, Y.; Henrichs, H.; Geers, V. C.; Martayan, C.; Hubert, A. M.; Thizy, O.; Tijani, A. (November 2012). "Multisite spectroscopic seismic study of the β Cep star V2052 Ophiuchi: inhibition of mixing by its magnetic field". Monthly Notices of the Royal Astronomical Society. 427 (1): 483–493. arXiv:1208.4250. Bibcode:2012MNRAS.427..483B. doi:10.1111/j.1365-2966.2012.21933.x.
8. Neiner, C.; Henrichs, H. F.; Floquet, M.; Frémat, Y.; Preuss, O.; Hubert, A. M.; Geers, V. C.; Tijani, A. H.; Nichols, J. S.; Jankov, S. (December 2003). "Rotation, pulsations and magnetic field in V 2052 Ophiuchi: A new He-strong star". Astronomy and Astrophysics. 411 (3): 565–579. Bibcode:2003A&A...411..565N. doi:10.1051/0004-6361:20031342.
9. Neiner, C.; Alecian, E.; Briquet, M.; Floquet, M.; Frémat, Y.; Martayan, C.; Thizy, O.; MiMeS Collaboration (January 2012). "Detecting and modelling the magnetic field of the β Cephei star V 2052 Ophiuchi". Astronomy and Astrophysics. 537: A148. Bibcode:2012A&A...537A.148N. doi:10.1051/0004-6361/201117941.
10. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (October 12, 2010). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1). Oxford University Press (OUP): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. ISSN 0035-8711.
11. "V2052 Oph -- beta Cep Variable". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-02-07.
12. Jerzykiewicz, Mikolaj (October 1972). "HR 6684: A New Beta Cephei Type Variable Star". Publications of the Astronomical Society of the Pacific. 84 (501): 718–720. Bibcode:1972PASP...84..718J. doi:10.1086/129368.
13. McNamara, D. H.; Bills, B. G. (October 1973). "Photometric and Spectrographic Observations of HR 6684". Publications of the Astronomical Society of the Pacific. 85 (507): 632–636. Bibcode:1973PASP...85..632M. doi:10.1086/129517.
14. Kukarkin, B. V.; Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (October 1973). "59th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 834: 1. Bibcode:1973IBVS..834....1K. Retrieved 7 February 2023.
15. Cugier, H.; Dziembowski, W. A.; Pamyatnykh, A. A. (November 1994). "Nonadiabatic observables in β Cephei models". Astronomy and Astrophysics. 291: 143–154. Bibcode:1994A&A...291..143C.