Astronomy:HD 28843

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Short description: Variable star in the constellation Eridanus
HD 28843
Eridanus constellation map.svg
Red circle.svg
Location of HD 28843 (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Eridanus
Right ascension  04h 32m 37.55373s[1]
Declination −03° 12′ 34.3448″[1]
Apparent magnitude (V) 5.70 - 5.84[2]
Characteristics
Spectral type B9III[3]
U−B color index −0.55[4]
B−V color index −0.14[4]
Variable type SX Arietis[5]
Astrometry
Radial velocity (Rv)18±7[3] km/s
Proper motion (μ) RA: 18.227±0.068[1] mas/yr
Dec.: −16.177±0.054[1] mas/yr
Parallax (π)5.8958 ± 0.0608[1] mas
Distance553 ± 6 ly
(170 ± 2 pc)
Absolute magnitude (MV)−0.7[6]
Details
Mass4.20±0.6[7] M☉
Radius3.4[1] R☉
Luminosity324+57
−48[7] L☉
Surface gravity (log g)3.86[1] cgs
Temperature14800±200[7] K
Metallicity [Fe/H]−0.166[8] dex
Rotation1.37381±0.00001 d[9]
Rotational velocity (v sin i)91[7] km/s
Other designations
DZ Eri, HR 1441, HIP 21192, SAO 131279[10]
Database references
SIMBADdata
A light curve for DZ Eridani, plotted from TESS data[11]

HD 28843, also known as HR 1441 and DZ Eridani, is a star about 550 light years from the Earth, in the constellation Eridanus.[1] It is a 5th magnitude star, so it will be faintly visible to the naked eye of an observer far from city lights. It is a variable star, whose brightness varies slightly from 5.70 to 5.84 during its 1.374 day rotation period.[2][9] It is a member of the μ Tauri Association, a group of young stars within the larger Cassiopeia-Taurus Structure.[3]

In 1969 Mercedes Jaschek et al. determined that HD 28843 is a helium-weak star, based on its B-V color index being bluer (more negative) than would be expected for a star with its spectral type.[12] In 1977, Robert Davis reported that the star has an overabundance of silicon.[13] It is classified as a chemically peculiar star.[14]

Henning Jorgensen et al. reported that HD 28843 was a "suspected variable star" in 1971.[15] The variability of the star was firmly established in 1977 by Holger Pedersen and Bjarne Thomsen, during a spectroscopic and photometric study of helium weak and helium strong stars. They determined its period to be 1.374±0.006 days.[16] In 1978 the star was given the variable star designation DZ Eridani.[17]

Ermanno Borra et al. reported in 1983 the detection of the magnetic field of HD 28843, and estimated its strength to be a few hundred gauss.[18] Later data from the International Ultraviolet Explorer implied a field strength of 250 gauss.[19]

M. Farthmann et al. reported in 1994 that high spectral resolution observations of the 4471Å spectral line of neutral helium can be explained if HD 28843 has two helium-enriched circular "caps" separated by a region with a dramatically lower helium abundance.[20]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 Manfroid, J.; Mathys, G. (July 1984). "On the Photometric Variations of HD 28843 and HD 29009". Information Bulletin on Variable Stars 2551: 1. Bibcode: 1984IBVS.2551....1M. https://ibvs.konkoly.hu/pub/ibvs/2501/2551.pdf. Retrieved 4 March 2023. 
  3. ↑ 3.0 3.1 3.2 Gagné, Jonathan; David, Trevor J.; Mamajek, Eric E.; Mann, Andrew W.; Faherty, Jacqueline K.; Bédard, Antoine (November 2020). "The μ Tau Association: A 60 Myr Old Coeval Group at 150 pc from the Sun". The Astrophysical Journal 903 (2): 96. doi:10.3847/1538-4357/abb77e. Bibcode: 2020ApJ...903...96G. 
  4. ↑ 4.0 4.1 Feinstein, A. (April 1978). "Photoelectric measures of hydrogen lines in helium-weak stars". Revista Mexicana de Astronomía y Astrofísica 2: 331–337. Bibcode: 1978RMxAA...2..331F. 
  5. ↑ 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. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S. 
  6. ↑ Eggen, O. J. (April 1977). "Is star formation bimodal? II. The nearest early-type stars". Publications of the Astronomical Society of the Pacific 89: 187–204. doi:10.1086/130099. Bibcode: 1977PASP...89..187E. 
  7. ↑ 7.0 7.1 7.2 7.3 Shultz, M. E.; Owocki, S. P.; ud-Doula, A.; Biswas, A.; Bohlender, D.; Chandra, P.; Das, B.; David-Uraz, A. et al. (June 2022). "MOBSTER - VI. The crucial influence of rotation on the radio magnetospheres of hot stars". Monthly Notices of the Royal Astronomical Society 513 (1): 1429–1448. doi:10.1093/mnras/stac136. Bibcode: 2022MNRAS.513.1429S. 
  8. ↑ Cardiel, Nicolás; Zamorano, Jaime; Carrasco, Josep Manel; Masana, Eduard; Bará, Salvador; González, Rafael; Izquierdo, Jaime; Pascual, Sergio et al. (23 July 2021). "RGB photometric calibration of 15 million Gaia stars". Monthly Notices of the Royal Astronomical Society 507 (1): 318–329. doi:10.1093/mnras/stab2124. ISSN 0035-8711. Bibcode: 2021MNRAS.507..318C. 
  9. ↑ 9.0 9.1 Waelkens, C. (July 1985). "Photometric variations and period determination of eight southern CP stars". Astronomy and Astrophysics Supplement Series 61: 127–139. Bibcode: 1985A&AS...61..127W. 
  10. ↑ "HD 28843 -- Rotating Variable". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+28843+--+Rotating+Variable. 
  11. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  12. ↑ Jaschek, Mercedes; Jaschek, Carlos; Arnal, Marcelo (October 1969). "Helium-Weak Stars". Publications of the Astronomical Society of the Pacific 81 (482): 650–656. doi:10.1086/128832. Bibcode: 1969PASP...81..650J. 
  13. ↑ Davis, R. J. (April 1977). "Spectral classification and U, B, V, Hbeta photometry". Astrophysical Journal 213: 105–110. doi:10.1086/155134. Bibcode: 1977ApJ...213..105D. 
  14. ↑ Bonsack, W. K.; Dyck, H. M. (September 1983). "Infrared colors of the chemically peculiar stars of the upper main sequence". Astronomy and Astrophysics 125: 29–33. Bibcode: 1983A&A...125...29B. 
  15. ↑ Jørgensen, H. E.; Johansen, K. T.; Olsen, E. H. (May 1971). "Variability of A and F main sequence stars". Astronomy and Astrophysics 12: 223–231. Bibcode: 1971A&A....12..223J. 
  16. ↑ Pedersen, H.; Thomsen, B. (October 1977). "Spectrum and photometric variability of He-weak and He-strong stars". Astronomy and Astrophysics Supplement Series 30: 11–25. Bibcode: 1977A&AS...30...11P. 
  17. ↑ Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (April 1979). "64th Name-List of Variable Stars". Information Bulletin on Variable Stars 1581: 1. Bibcode: 1979IBVS.1581....1K. https://ibvs.konkoly.hu/pub/ibvs/1501/1581.pdf. Retrieved 25 February 2023. 
  18. ↑ Borra, E. F.; Landstreet, J. D.; Thompson, I. (September 1983). "The magnetic fields of the helium-weak B stars". Astrophysical Journal Supplement Series 53: 151–167. doi:10.1086/190889. Bibcode: 1983ApJS...53..151B. 
  19. ↑ Brown, D. N.; Shore, S. N.; Barker, P. K.; Sonneborn, G. (December 1984). "Magnetospheres and winds in the helium weak stars: observations of C IV in upper main sequence CP stars". NASA Conference Publication 2349: 487–490. Bibcode: 1984NASCP2349..487B. 
  20. ↑ Farthmann, M.; Dreizler, S.; Heber, U.; Hunger, K. (November 1994). "Stratification of helium in the photospheres of the helium-weak stars HD 28843 and HD 49333". Astronomy and Astrophysics 291: 919–927. Bibcode: 1994A&A...291..919F. 



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