Star in the constellation Eridanus
HD 17925 is avariable star in theequatorial constellation ofEridanus . It has theGould designation 32 G. Eridani and thevariable star designation EP Eri. The star has a yellow-orange hue and is dimly visible to the naked eye in good seeing conditions with anapparent visual magnitude that varies from 6.03 down to 6.08.[ 18] light years from theSun based onparallax ,[ 2] radial velocity of +18 km/s.[ 8] [ 13] [ 4] Scorpio–Centaurus Complex .[ 19]
Avisual band light curve for EP Eridani, adapted from Cutispoto (1992)[ 20] Thestellar classification of HD 17925 is K1V,[ 5] K-type main-sequence star that is engaged incore hydrogen fusion . It is anactive star[ 4] RS Canum Venaticorum variable ,[ 18] rotational modulation with a period of 6.9 days, and has been observed to flare.[ 7] [ 15] projected rotational velocity of 4.8 km/s.[ 14] rotation period of 6.6 days days can be determined from its activity cycle.[ 13] [ 10] mass of the Sun and 85%[ 11] Sun's radius . It is radiating 41%[ 2] luminosity of the Sun from itsphotosphere at aneffective temperature of 5,225 K.[ 12]
The presence of an unseen companion has been suggested based on variations in the widths ofabsorption lines in the star'sphotosphere .[ 4] spectroscopic binary .[ 11] [ 13] infrared excess has been detected around this star, most likely indicating the presence of acircumstellar disk at a radius of 17.9 AU . The temperature of this dust is 52 K.[ 21]
^ Roman, Nancy G. (1987)."Identification of a constellation from a position" .Publications of the Astronomical Society of the Pacific 99 (617): 695.Bibcode :1987PASP...99..695R .doi :10.1086/132034 Constellation record for this object atVizieR .^a b c d e f g h 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DR3 record for this source atVizieR .^ Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)",Catalogue of Eggen's UBV Data. SIMBAD ,Bibcode :1986EgUBV........0M . ^a b c d Pandey, J. C.; Singh, K. P. (July 2008), "A study of X-ray flares - I. Active late-type dwarfs",Monthly Notices of the Royal Astronomical Society ,387 (4): 1627−1648,arXiv :0805.3882 Bibcode :2008MNRAS.387.1627P ,doi :10.1111/j.1365-2966.2008.13342.x S2CID 18111371 . ^a b Montes, D.; et al. (2001), "Late-type members of young stellar kinematic groups - I. Single stars",Monthly Notices of the Royal Astronomical Society ,328 (1):45– 63,arXiv :astro-ph/0106537 Bibcode :2001MNRAS.328...45M ,doi :10.1046/j.1365-8711.2001.04781.x S2CID 55727428 . ^a b Vieytes, M.; et al. (May 2007), Heinzel, P.; Dorotovič, I.; Rutten, R. J. (eds.), "Chromospheric Activity in K Stars",The Physics of Chromospheric Plasmas. Proceedings of the conference held 9-13 October, 2006 at the University of Coimbra in Coimbra, Portugal , ASP Conference Series, vol. 368, San Francisco: Astronomical Society of the Pacific, p. 265,Bibcode :2007ASPC..368..265V . ^a b Abbott, B. P.; Pomerance, B. H.; Ambruster, C. W. (March 1995), "UBVRI Photometry of the Solar Neighborhood Pleiades-Age K Dwarfs HD 17925 and HD 1405",Bulletin of the American Astronomical Society ,27 : 842,Bibcode :1995AAS...186.2210A . ^a b Karataș, Yüksel; Bilir, Selçuk; Eker, Zeki; Demircan, Osman; Liebert, James; Hawley, Suzanne L.; Fraser, Oliver J.; Covey, Kevin R.; Lowrance, Patrick; Kirkpatrick, J. Davy; Burgasser, Adam J. (2004)."Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution" .Monthly Notices of the Royal Astronomical Society .349 (3):1069– 1092.arXiv :astro-ph/0404219 Bibcode :2004MNRAS.349.1069K .doi :10.1111/j.1365-2966.2004.07588.x S2CID 15290475 . ^ Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics",Astronomy and Astrophysics ,501 (3):941– 947,arXiv :0811.3982 Bibcode :2009A&A...501..941H ,doi :10.1051/0004-6361/200811191 ,S2CID 118577511 . ^a b c Luck, R. Earle (March 2018), "Abundances in the Local Region. III. Southern F, G, and K Dwarfs",The Astronomical Journal ,155 (3): 31,Bibcode :2018AJ....155..111L ,doi :10.3847/1538-3881/aaa9b5 S2CID 125765376 , 111. ^a b c Ambruster, C. W.; et al. (October 2003), Brown, A.; Harper, G. M.; Ayres, T. R. (eds.), "The Radii of Solar Neighborhood ZAMS Stars",The Future of Cool-Star Astrophysics: 12th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun (2001 July 30 - August 3) , vol. 12, pp. 912– 915,Bibcode :2003csss...12..912A . ^a b Kovtyukh, V. V.; et al. (2003), "High precision effective temperatures for 181 F-K dwarfs from line-depth ratios",Astronomy and Astrophysics 411 (3):559– 564,arXiv :astro-ph/0308429 Bibcode :2003A&A...411..559K ,doi :10.1051/0004-6361:20031378 ,S2CID 18478960 . ^a b c d e Maldonado, J.; et al. (October 2010), "A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups",Astronomy and Astrophysics ,521 : A12,arXiv :1007.1132 Bibcode :2010A&A...521A..12M ,doi :10.1051/0004-6361/201014948 ,S2CID 119209183 . ^a b Mishenina, T. V.; et al. (November 2012), "Activity and the Li abundances in the FGK dwarfs",Astronomy & Astrophysics ,547 : 8,arXiv :1210.6843 Bibcode :2012A&A...547A.106M ,doi :10.1051/0004-6361/201118412 ,S2CID 119287319 , A106. ^a b Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008), "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics",The Astrophysical Journal ,687 (2):1264– 1293,arXiv :0807.1686 Bibcode :2008ApJ...687.1264M ,doi :10.1086/591785 ,S2CID 27151456 . ^ Gould, Benjamin Apthorp (1879),"Uranometria Argentina catalog of bright southern stars" ,Resultados del Observatorio Nacional Argentino en Cordoba ,1 , Buenos Aires,Bibcode :1879RNAO....1.....G , retrieved2012-05-08 ^ "HD 17925" ,SIMBAD Centre de données astronomiques de Strasbourg , retrieved2021-01-11 .^a b Samus', N. N; et al. (2017), "General catalogue of variable stars",Astronomy Reports , GCVS 5.1,61 (1): 80,Bibcode :2017ARep...61...80S ,doi :10.1134/S1063772917010085 ,S2CID 125853869 . ^ Cayrel de Strobel, G.; Cayrel, R. (July 1989), "Strong lithium in the very nearby K-dwarf HD 17925",Astronomy and Astrophysics ,218 (1– 2):L9– L12,Bibcode :1989A&A...218L...9C ^ Cutispoto, G. (November 1992). "Long-term monitoring of active stars. II. UBV (RI)c observations at ESO during January-March 1989".Astronomy and Astrophysics Supplement Series .95 :397– 413.Bibcode :1992A&AS...95..397C . ^ Eiroa, C.; et al. (July 2013), "DUst around NEarby Stars. The survey observational results",Astronomy & Astrophysics ,555 : A11,arXiv :1305.0155 Bibcode :2013A&A...555A..11E ,doi :10.1051/0004-6361/201321050 ,S2CID 377244 . Christian, D. J.; Mathioudakis, M.; Jevremović, D. (October 2008), "6 Li in the Atmosphere of GJ 117 Revisited",The Astrophysical Journal ,686 (1):542– 547,arXiv :0807.3693 Bibcode :2008ApJ...686..542C ,doi :10.1086/591727 ,S2CID 346207
