66 Eridani

{{short description|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=10|mark_link=66 Eridani

|x=124|y=168

}}

|caption=Location of 66 Eridani (circled)

}}

{{Starbox observe

|epoch=J2000

|constell=Eridanus

|ra={{RA|05|06|45.65314}}{{cite journal|title=Validation of the new Hipparcos reduction|author=van Leeuwen, F.|display-authors=etal|journal=Astronomy and Astrophysics|volume=474|issue=2|pages=653–664|date=2007|arxiv=0708.1752|bibcode=2007A&A...474..653V|doi=10.1051/0004-6361:20078357|s2cid=18759600}}

|dec={{DEC|-04|39|18.5939}}

|appmag_v=5.12{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|author1=Ducati, J. R.|year=2002}}

}}

{{Starbox character

|class=B9V{{cite journal|bibcode=1999MSS...C05....0H|title=Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5|journal=Michigan Spectral Survey|volume=5|pages=0|author1=Houk, N.|author2=Swift, C.|year=1999}}

|b-v=-0.06{{cite journal|author1=Mermilliod, J.-C.|title=Compilation of Eggen's UBV data, transformed to UBV (unpublished)|journal=Catalogue of Eggen's UBV Data|url=http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1|date=1986|bibcode= 1986EgUBV........0M}}

|u-b=-0.16

|variable=α² CVn?{{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 |date=2017 |volume=61 |issue=1 |page=80 |doi=10.1134/S1063772917010085 }}

}}

{{Starbox astrometry

|radial_v={{val|32.28|0.10}}

|prop_mo_ra=10.70

|prop_mo_dec=−0.78

|parallax=10.56

|p_error=0.34

|parallax_footnote=

|absmag_v=0.37{{citation

| title=Search for low-mass PMS companions around X-ray selected late B stars

| last1=Hubrig | first1=S. | last2=Le Mignant | first2=D.

| last3=North | first3=P. | last4=Krautter | first4=J.

| journal=Astronomy and Astrophysics | display-authors=1

| volume=372 | pages=152–164 | date=June 2001

| doi=10.1051/0004-6361:20010452 | bibcode=2001A&A...372..152H

| arxiv=astro-ph/0103201 | s2cid=17507782 | postscript=. }}

}}

{{Starbox orbit

|reference={{cite journal|bibcode=2011A&A...529A.160M|doi=10.1051/0004-6361/201016302|arxiv=1102.4661|title=Chemical spots in the absence of magnetic field in the binary Hg Mn star 66 Eridani|journal=Astronomy & Astrophysics|volume=529|pages=A160|year=2011|last1=Makaganiuk|first1=V.|last2=Kochukhov|first2=O.|last3=Piskunov|first3=N.|last4=Jeffers|first4=S. V.|last5=Johns-Krull|first5=C. M.|last6=Keller|first6=C. U.|last7=Rodenhuis|first7=M.|last8=Snik|first8=F.|last9=Stempels|first9=H. C.|last10=Valenti|first10=J. A.|s2cid=118419097}}

|period_unitless=5.5226013 ± 0.0000020 d

|periastron={{val|2441356.499|0.017}}

|eccentricity={{val|0.0844|0.0013}}

|periarg={{val|160.9|1.1}}

|k1={{val|102.83|0.20}}

|k2={{val|100.35|0.19}}

}}

{{Starbox detail

|source=

|component1=66 Eri A

|mass={{val|2.629|0.032}}

|radius={{val|1.948|0.063}}

|temperature=11,077

|luminosity={{val|51.3|3.3}}

|gravity={{val|4.28|0.03}}

|rotational_velocity={{val|17.1|0.2}}

|age_myr=30

|component2=66 Eri B

|mass2={{val|2.566|0.032}}

|radius2={{val|1.919|0.061}}

|temperature2=10,914

|luminosity2={{val|46.9|3.0}}

|gravity2={{val|4.28|0.03}}

|rotational_velocity2={{val|16.9|0.2}}

}}

{{Starbox catalog

|names={{odlist|V=EN Eri|BD=-04°1044|HD=32964|HIP=23794|HR=1657|SAO=131777}}{{cite simbad|title=* 66 Eri|access-date=13 August 2017}}

}}

{{Starbox reference

|Simbad=66+Eri

}}

{{Starbox end}}

66 Eridani is a binary star in the constellation of Eridanus. The combined apparent magnitude of the system is 5.12 on average. Parallax measurements by Hipparcos put the system at some 309 light-years (95 parsecs) away. It lies half a degree northwest of beta Eridani.

This is a spectroscopic binary: the two stars cannot be individually resolved, but periodic Doppler shifts in its spectrum mean there must be orbital motion. The two stars orbit each other every 5.5 days. Their orbit is fairly circular, with an eccentricity of 0.0844.

The combined spectrum of 66 Eridani matches that of a B-type main-sequence star, and the two stars have similar masses. The spectrum also shows excess of mercury and manganese, as it is a type of chemically peculiar star called a mercury-manganese star. 66 Eridani is an Alpha² Canum Venaticorum variable. For this reason, it has been given the designation EN Eridani.