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 4471Åspectral 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]
^ abFeinstein, 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.
^ abWaelkens, 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.
^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.
^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.