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HD 28843

{{Short description|Variable star in the constellation Eridanus}}

{{Starbox begin}}

{{Starbox image

| image=

{{Location mark

|image=Eridanus constellation map.svg|alt=|float=center|width=240

|label=|position=right

|mark=Red circle.svg|mark_width=8|mark_link=HD 28843

|x=284|y=122

}}

|caption=Location of HD 28843 (circled)

}}

{{Starbox observe

| epoch = J2000.0

| ra = {{RA|04|32|37.55373}}

| dec = {{DEC|-03|12|34.3448}}

| appmag_v = 5.70 - 5.84

| constell = Eridanus

}}

{{Starbox character

| class = B9III

| b-v = −0.14

| u-b = −0.55

| variable = SX Arietis

}}

{{Starbox astrometry

| radial_v = {{val|18|7}}

| prop_mo_ra = {{val|18.227|0.068}}

| prop_mo_dec = {{val|-16.177|0.054}}

| parallax = 5.8958

| p_error = 0.0608

| parallax_footnote =

| absmag_v = −0.7

}}

{{Starbox detail

| source =

| mass = {{val|4.20|0.6}}

| radius = 3.4

| luminosity = {{val|324|57|48}}

| gravity = 3.86

| temperature = {{val|14,800|200}}

| metal =

| metal_fe = −0.166

| rotation = {{val|1.37381|0.00001|ul=d}}

| rotational_velocity = 91

| age_myr =

| age_gyr =

}}

{{Starbox catalog

| names = DZ Eri, HR 1441, HIP 21192, SAO 131279

}}

{{Starbox reference

| Simbad = DZ+Eri

}}

{{Starbox end}}

Image:DZEriLightCurve.png for DZ Eridani, plotted from TESS 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 {{val|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

{{Reflist|refs=

{{cite journal | last1 = Cardiel | first1 = Nicolás | last2 = Zamorano | first2 = Jaime | last3 = Carrasco | first3 = Josep Manel | last4 = Masana | first4 = Eduard | last5 = Bará | first5 = Salvador | last6 = González | first6 = Rafael | last7 = Izquierdo | first7 = Jaime | last8 = Pascual | first8 = Sergio | last9 = Sánchez de Miguel | first9 = Alejandro | title = RGB photometric calibration of 15 million Gaia stars | journal = Monthly Notices of the Royal Astronomical Society | date = 23 July 2021 | volume = 507 | issue = 1 | pages = 318–329 | issn = 0035-8711 | eissn = 1365-2966 | doi = 10.1093/mnras/stab2124 | bibcode = 2021MNRAS.507..318C | arxiv = 2107.08734 | doi-access = free}}

{{cite web

| title=MAST: Barbara A. Mikulski Archive for Space Telescopes

| url=https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html

| publisher=Space Telescope Science Institute | access-date=3 March 2023}}

{{cite Gaia DR3|3204585226803914368}}

{{cite journal

| last1=Manfroid | first1=J. | last2=Mathys | first2=G.

| title=On the Photometric Variations of HD 28843 and HD 29009

| journal=Information Bulletin on Variable Stars

| date=July 1984 | volume=2551 | page=1 | bibcode=1984IBVS.2551....1M

| url=https://ibvs.konkoly.hu/pub/ibvs/2501/2551.pdf |access-date=4 March 2023}}

{{cite simbad

| title= HD 28843 -- Rotating Variable | access-date=2023-03-03}}

{{cite journal

| bibcode=2017ARep...61...80S

| title=General catalogue of variable stars: Version GCVS 5.1

| last1=Samus' | first1=N. N. | last2=Kazarovets | first2=E. V.

| last3=Durlevich | first3=O. V.

| last4=Kireeva | first4=N. N. | last5=Pastukhova | first5=E. N.

| journal=Astronomy Reports | year=2017 | volume=61 | issue=1 | page=80

| doi=10.1134/S1063772917010085 | s2cid=125853869 | doi-access=free }}

{{cite journal

| last1=Gagné | first1=Jonathan | last2=David | first2=Trevor J. | last3=Mamajek | first3=Eric E.

| last4=Mann | first4=Andrew W. | last5=Faherty | first5=Jacqueline K.

| last6=Bédard | first6=Antoine

| title=The μ Tau Association: A 60 Myr Old Coeval Group at 150 pc from the Sun

| journal=The Astrophysical Journal |date=November 2020

| volume=903 | issue=2 | page=96 | doi=10.3847/1538-4357/abb77e | arxiv=2008.06139 | bibcode=2020ApJ...903...96G | doi-access=free }}

{{cite journal

| last1=Pedersen | first1=H. | last2=Thomsen | first2=B. | bibcode=1977A&AS...30...11P

| title=Spectrum and photometric variability of He-weak and He-strong stars

| journal=Astronomy and Astrophysics Supplement Series | date=October 1977 | volume=30 |pages=11–25 }}

{{cite journal

| last1=Kholopov | first1=P. N. | last2=Kukarkina | first2=N. P. | last3=Perova | first3=N. B.

| title=64th Name-List of Variable Stars | journal=Information Bulletin on Variable Stars

| date=April 1979 | volume=1581 | page=1 | url=https://ibvs.konkoly.hu/pub/ibvs/1501/1581.pdf

| bibcode=1979IBVS.1581....1K | access-date=25 February 2023}}

{{cite journal

| last1=Shultz | first1=M. E. | last2=Owocki | first2=S. P. | last3=ud-Doula | first3=A.

| last4=Biswas | first4=A. | last5=Bohlender | first5=D. | last6=Chandra | first6=P.

| last7=Das | first7=B. | last8=David-Uraz | first8=A. | last9=Khalack | first9=V.

| last10=Kochukhov | first10=O. | last11=Landstreet | first11=J. D. | last12=Leto | first12=P.

| last13=Monin | first13=D. | last14=Neiner | first14=C. | last15=Rivinius | first15=Th.

| last16=Wade | first16=G. A.

| title=MOBSTER - VI. The crucial influence of rotation on the radio magnetospheres of hot stars

| journal=Monthly Notices of the Royal Astronomical Society

| date=June 2022 | volume=513 | issue=1 | pages=1429–1448

| doi=10.1093/mnras/stac136 | doi-access=free | bibcode=2022MNRAS.513.1429S | arxiv=2201.05512 }}

{{cite journal

| last1=Jaschek | first1=Mercedes | last2=Jaschek | first2=Carlos | last3=Arnal | first3=Marcelo

| title=Helium-Weak Stars | journal=Publications of the Astronomical Society of the Pacific

| date=October 1969 | volume=81 | issue=482 | pages=650–656

| doi=10.1086/128832 | bibcode=1969PASP...81..650J | doi-access=free }}

{{cite journal

| last1=Jørgensen | first1=H. E. | last2=Johansen | first2=K. T. | last3=Olsen | first3=E. H.

| title=Variability of A and F main sequence stars | journal=Astronomy and Astrophysics

| date=May 1971 | volume=12 | pages=223–231 | bibcode=1971A&A....12..223J }}

{{cite journal

| last1=Eggen | first1=O. J.

| title=Is star formation bimodal? II. The nearest early-type stars

| journal=Publications of the Astronomical Society of the Pacific

| date=April 1977 | volume=89 | pages=187–204 | doi=10.1086/130099 | bibcode=1977PASP...89..187E

| doi-access=free }}

{{cite journal

| last1=Feinstein | first1=A.

| title=Photoelectric measures of hydrogen lines in helium-weak stars

| journal=Revista Mexicana de Astronomía y Astrofísica

| date=April 1978 | volume=2 | pages=331–337 | bibcode=1978RMxAA...2..331F }}

{{cite journal

| last1=Davis | first1=R. J.

| title=Spectral classification and U, B, V, Hbeta photometry

| journal=Astrophysical Journal | date=April 1977 | volume=213 | pages=105–110

| doi=10.1086/155134 | bibcode=1977ApJ...213..105D }}

{{cite journal

| last1=Borra | first1=E. F. | last2=Landstreet | first2=J. D. | last3=Thompson | first3=I.

| title=The magnetic fields of the helium-weak B stars

| journal=Astrophysical Journal Supplement Series | date=September 1983 | volume=53 | pages=151–167

| doi=10.1086/190889 | bibcode=1983ApJS...53..151B }}

{{cite journal

| last1=Bonsack | first1=W. K. | last2=Dyck | first2=H. M.

| title=Infrared colors of the chemically peculiar stars of the upper main sequence

| journal=Astronomy and Astrophysics

| date=September 1983 | volume=125 | pages=29–33 | bibcode=1983A&A...125...29B }}

{{cite journal

| last1=Brown | first1=D. N. | last2=Shore | first2=S. N.

| last3=Barker | first3=P. K. | last4=Sonneborn | first4=G.

| title=Magnetospheres and winds in the helium weak stars: observations of C IV in upper main sequence CP stars

| journal=NASA Conference Publication | date=December 1984

| volume=2349 | pages=487–490 | bibcode=1984NASCP2349..487B }}

{{cite journal

| last1=Waelkens | first1=C.

| title=Photometric variations and period determination of eight southern CP stars

| journal=Astronomy and Astrophysics Supplement Series

| date=July 1985 | volume=61 | pages=127–139 | bibcode=1985A&AS...61..127W }}

{{cite journal

| last1=Farthmann | first1=M. | last2=Dreizler | first2=S.

| last3=Heber | first3=U. | last4=Hunger | first4=K.

| title=Stratification of helium in the photospheres of the helium-weak stars HD 28843 and HD 49333

| journal=Astronomy and Astrophysics

| date=November 1994 | volume=291 | pages=919–927 | bibcode=1994A&A...291..919F }}

}}

{{Stars of Eridanus}}

{{DEFAULTSORT:HD 28843}}

Category:Eridanus (constellation)

021192

028843

Eridani, DZ

Category:SX Arietis variables

Category:B-type giants

Category:Helium-weak stars