Star in the constellation Ursa Major
HR 4072 Observation dataEpoch J2000 Equinox J2000 Constellation Ursa Major Right ascension 10h 24m 07.84801s [ 2] Declination +65° 33′ 59.1239″[ 2] Apparent magnitude (V)4.94[ 3] Characteristics Spectral type A1:VpSiSrHg[ 4] B−Vcolor index ± 0.012[ 3] Variable type α2 CVn [ 5] Astrometry Radial velocity (Rv )± 0.03[ 6] km/s Proper motion (μ)RA: −9.427[ 2] mas /yr Dec.: −20.994[ 2] mas /yr Parallax (π)9.61± 0.20 mas [ 2] Distance 339 ± 7 ly pc ) Absolute magnitude (MV )−0.15[ 3] Orbit [ 6] Period (P)± 0.000010 dSemi-major axis (a)± 0.001 mas Eccentricity (e)± 0.0009Longitude of the node (Ω)± 0.13Periastron epoch (T)± 0.005 JD Argument of periastron (ω)± 0.20Semi-amplitude 1 )± 0.04Semi-amplitude (K2 )± 0.09Details[ 6] A Mass ± 0.153M ☉ Radius ± 0.11R ☉ Luminosity ± 8L ☉ Surface gravity (log g )± 0.05cgs Temperature ± 100K Metallicity [ M / H ] {\displaystyle {\begin{smallmatrix}\left[{\ce {M}}/{\ce {H}}\right]\end{smallmatrix}}} ± 0.04Metallicity [Fe/H] +0.39[ 7] dex Rotational velocity (v sin i )≤4.2 km/s B Mass ± 0.094M ☉ Radius ± 0.06R ☉ Luminosity ± 1.0L ☉ Surface gravity (log g )± 0.05cgs Temperature ± 140K Metallicity [ M / H ] {\displaystyle {\begin{smallmatrix}\left[{\ce {M}}/{\ce {H}}\right]\end{smallmatrix}}} ± 0.07Rotational velocity (v sin i )± 2.1Other designations ET UMa ,BD +66 664GJ 9327HD 89822HIP 50933HR 4072SAO 15163PPM 17427PLX 2433TYC 4150-1302-1IRAS 10205+65492MASS J10240782+6533590[ 8] Database references SIMBAD data
HR 4072 is abinary star [ 9] circumpolar constellation ofUrsa Major . It has thevariable star designation ET Ursae Majoris , abbreviated ET UMa,[ 5] HR 4072 is the system's designation from theBright Star Catalogue naked eye with anapparent visual magnitude that fluctuates around 4.94.[ 3] light years from theSun based onparallax measurements.[ 2] radial velocity measurement is poorly constrained, but it appears to be drifting closer to the Sun at the rate of around −3 km/s.[ 3]
This is a double-linedspectroscopic binary [ 7] orbital period of 11.58 days and aneccentricity of 0.29.[ 6] R. H. Baker in 1912, then later revised.[ 10] [ 6]
The primary, designated component A, is anAp typechemically-peculiar star [ 11] [ 12] [ 13] stellar classification of A1:VpSiSrHg,[ 4] mercury-manganese star .[ 14] spectrum . It is anα2 Canum Venaticorum variable with an amplitude of 0.05 magnitude in theB (blue) band .[ 5] projected rotational velocity of 4.5 km/s.[ 7] effective temperature ofK [ 6]
The secondary component has been reported to have characteristics of anAm star .[ 12] F-type star with 1.73 times the size of the Sun and 1.71 times its mass. Its luminosity is about 10 times that of the Sun, or one-tenth of that of the primary, and it has an effective temperature ofK [ 6]
^ "MAST: Barbara A. Mikulski Archive for Space Telescopes" . Space Telescope Science Institute. Retrieved8 December 2021 .^a b c d e f Brown, A. G. A. ; et al. (Gaia collaboration ) (August 2018)."Gaia Data Release 2: Summary of the contents and survey properties" .Astronomy & Astrophysics 616 . A1.arXiv :1804.09365 Bibcode :2018A&A...616A...1G doi :10.1051/0004-6361/201833051 Gaia DR2 record for this source atVizieR .^a b c d e Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation".Astronomy Letters .38 (5): 331.arXiv :1108.4971 Bibcode :2012AstL...38..331A .doi :10.1134/S1063773712050015 .S2CID 119257644 . ^a b Abt, Helmut A.; Morrell, Nidia I. (1995)."The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars" .Astrophysical Journal Supplement .99 : 135.Bibcode :1995ApJS...99..135A .doi :10.1086/192182 ^a b c Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars".Astronomy Reports . 5.1.61 (1):80– 88.Bibcode :2017ARep...61...80S .doi :10.1134/S1063772917010085 .S2CID 125853869 . ^a b c d e f g Lester, Kathryn V.; Schaefer, Gail H.; Fekel, Francis C.; Gies, Douglas R.; Henry, Todd J.; Jao, Wei-Chun; Paredes, Leonardo A.; Hubbard-James, Hodari-Sadiki; Farrington, Christopher D.; Gordon, Kathryn D.; Chojnowski, S. Drew; Monnier, John D.; Kraus, Stefan; Bouquin, Jean-Baptiste Le; Anugu, Narsireddy (November 2022)."Visual Orbits of Spectroscopic Binaries with the CHARA Array. IV. HD 61859, HD 89822, HD 109510, and HD 191692" .The Astronomical Journal .164 (6): 228.arXiv :2209.09993 Bibcode :2022AJ....164..228L .doi :10.3847/1538-3881/ac9385 ISSN 1538-3881 . ^a b c Takeda, Yoichi; et al. (October 2018). "Photospheric carbon, nitrogen, and oxygen abundances of A-type main-sequence stars*".Publications of the Astronomical Society of Japan .70 (5): 91.arXiv :1807.06265 Bibcode :2018PASJ...70...91T .doi :10.1093/pasj/psy091 .S2CID 119258233 . 91. ^ "ET UMa" .SIMBAD Centre de données astronomiques de Strasbourg . Retrieved2019-12-06 .^ Eggleton, P. P.; Tokovinin, A. A. (September 2008)."A catalogue of multiplicity among bright stellar systems" .Monthly Notices of the Royal Astronomical Society .389 (2):869– 879.arXiv :0806.2878 Bibcode :2008MNRAS.389..869E .doi :10.1111/j.1365-2966.2008.13596.x S2CID 14878976 . ^ Nariai, K. (1970). "Orbit of the Double-Line Spectroscopic Binary HR4072(Ap)".Publications of the Astronomical Society of Japan .22 : 113.Bibcode :1970PASJ...22..113N . ^ Renson, P.; Manfroid, J. (2009)."Catalogue of Ap, HGMN and Am stars" .Astronomy and Astrophysics .498 (3): 961.Bibcode :2009A&A...498..961R .doi :10.1051/0004-6361/200810788 ^a b Popper, Daniel M. (1971)."Some Double-Lined Eclipsing Binaries with Metallic-Line Spectra" .The Astrophysical Journal .169 : 549.Bibcode :1971ApJ...169..549P .doi :10.1086/151173 ^ Chen, P. S.; Liu, J. Y.; Shan, H. G. (2017)."A New Photometric Study of Ap and Am Stars in the Infrared" .The Astronomical Journal .153 (5): 218.Bibcode :2017AJ....153..218C .doi :10.3847/1538-3881/aa679a ^ Ghazaryan, S.; Alecian, G. (2016)."Statistical analysis from recent abundance determinations in HgMn stars" .Monthly Notices of the Royal Astronomical Society .460 (2): 1912.Bibcode :2016MNRAS.460.1912G .doi :10.1093/mnras/stw911
