Location of HD 28843 (circled) | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04 32 37.55373 |
| Declination | −03° 12′ 34.3448″ |
| Apparent magnitude (V) | 5.70 - 5.84 |
| Characteristics | |
| Spectral type | B9III |
| U−B color index | −0.55 |
| B−V color index | −0.14 |
| Variable type | SX Arietis |
| Astrometry | |
| Radial velocity (Rv) | 18±7 km/s |
| Proper motion (μ) | RA: 18.227±0.068 mas/yr Dec.: −16.177±0.054 mas/yr |
| Parallax (π) | 5.8958 ± 0.0608 mas |
| Distance | 553 ± 6 ly (170 ± 2 pc) |
| Absolute magnitude (MV) | −0.7 |
| Details | |
| Mass | 4.20±0.6 M☉ |
| Radius | 3.4 R☉ |
| Luminosity | 324+57 −48 L☉ |
| Surface gravity (log g) | 3.86 cgs |
| Temperature | 14800±200 K |
| Metallicity | −0.166 dex |
| Rotation | 1.37381±0.00001 d |
| Rotational velocity (v sin i) | 91 km/s |
| Other designations | |
| DZ Eri, HR 1441, HIP 21192, SAO 131279 | |
| Database references | |
| SIMBAD | data |
HD 28843, also known as HR 1441 and DZ Eridani, is a star about 550 light years from the Earth, in the constellation Eridanus. 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. It is a member of the μ Tauri Association, a group of young stars within the larger Cassiopeia-Taurus Structure.
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. In 1977, Robert Davis reported that the star has an overabundance of silicon. It is classified as a chemically peculiar star.
Henning Jorgensen et al. reported that HD 28843 was a "suspected variable star" in 1971. 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. In 1978 the star was given the variable star designation DZ Eridani.
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. Later data from the International Ultraviolet Explorer implied a field strength of 250 gauss.
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.
References
- ^ 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.
- ^ Manfroid, J.; Mathys, G. (July 1984). "On the Photometric Variations of HD 28843 and HD 29009" (PDF). Information Bulletin on Variable Stars. 2551: 1. Bibcode:1984IBVS.2551....1M. Retrieved 4 March 2023.
- ^ 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. arXiv:2008.06139. Bibcode:2020ApJ...903...96G. doi:10.3847/1538-4357/abb77e.
- ^ 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.
- 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.
- 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. Bibcode:1977PASP...89..187E. doi:10.1086/130099.
- ^ Shultz, M. E.; Owocki, S. P.; ud-Doula, A.; Biswas, A.; Bohlender, D.; Chandra, P.; Das, B.; David-Uraz, A.; Khalack, V.; Kochukhov, O.; Landstreet, J. D.; Leto, P.; Monin, D.; Neiner, C.; Rivinius, Th.; Wade, G. A. (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. arXiv:2201.05512. Bibcode:2022MNRAS.513.1429S. doi:10.1093/mnras/stac136.
- Cardiel, Nicolás; Zamorano, Jaime; Carrasco, Josep Manel; Masana, Eduard; Bará, Salvador; González, Rafael; Izquierdo, Jaime; Pascual, Sergio; Sánchez de Miguel, Alejandro (23 July 2021). "RGB photometric calibration of 15 million Gaia stars". Monthly Notices of the Royal Astronomical Society. 507 (1): 318–329. arXiv:2107.08734. Bibcode:2021MNRAS.507..318C. doi:10.1093/mnras/stab2124. eISSN 1365-2966. ISSN 0035-8711.
- ^ 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.
- "HD 28843 -- Rotating Variable". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-03-03.
- "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 3 March 2023.
- Jaschek, Mercedes; Jaschek, Carlos; Arnal, Marcelo (October 1969). "Helium-Weak Stars". Publications of the Astronomical Society of the Pacific. 81 (482): 650–656. Bibcode:1969PASP...81..650J. doi:10.1086/128832.
- Davis, R. J. (April 1977). "Spectral classification and U, B, V, Hbeta photometry". Astrophysical Journal. 213: 105–110. Bibcode:1977ApJ...213..105D. doi:10.1086/155134.
- 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.
- 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.
- 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.
- Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (April 1979). "64th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 1581: 1. Bibcode:1979IBVS.1581....1K. Retrieved 25 February 2023.
- 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. Bibcode:1983ApJS...53..151B. doi:10.1086/190889.
- 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.
- 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.
