KS Persei is a binary system in the equatorialconstellationofPerseus. It is sometimes known as Bidelman's Star, named after William P. Bidelman.[10][2] The star is invisible to the naked eye with a mean apparent visual magnitude of 7.70.[2] As of 2018, the structure and evolutionary history of this system remain uncertain, although some form of mass transfer is likely to have occurred to explain the observed properties.[11]
The peculiar nature of the spectra for this star was noted in the Henry Draper Catalogue and was the subject of a study by W. P. Bidelman published in 1950. He found extremely weak lines of hydrogen, similar to those for Upsilon Sagittarii but at a lower temperature. The data strongly suggested the star has an abnormally low abundance of hydrogen in the stellar atmosphere. Bidelman noted that the radial velocity of the star is variable, demonstrating that it has an unseen companion.[12] Preliminary orbital elements for this single-lined spectroscopic binary were published in 1955 by J. F. Heard and O. Boshko, giving an orbital period of 359.7 days and with eccentricity of 0.27. They found a large mass function of 4.5, suggesting that the supergiant has lost mass and the companion is relatively massive.[13] The mass function was revised to 3.6±0.4 in 1988, suggesting the secondary is five times more massive than the primary.[6] Although the Gaia parallax is small (and the Hipparcos parallax is negative), KS Persei is thought to be less than 1,000 pc away. Older studies have suggested distances up to 3,900 pc.[6]
An analysis by G. Wallerstein and associates in 1967 showed that nitrogen is the second most abundant element in the primary, likely as a result of carbon cycling.[14]G. A. Bakos attempted to photometrically detect an eclipse but was unsuccessful. However, he did tentatively detect semiregular variation with a period of ~30 days and an amplitude of 0.1 magnitude. This variability was confirmed by K. Morrison and G. P. H. Willingale in 1987, and they discovered an additional five day cycle.[15] In 1982, J. S. Drilling and D. Schönberner detected a hot companion from spectra collected by the International Ultraviolet Explorer.[4] The system is an infrared source, and models of the infrared flux suggest it is being emitted by circumstellar dust heated to 1,100 K.[6] It is possible that the companion is obscured by dust.[8]
^Boulon, J.; Fehrenbach, C.; Duflot, A.; Rebeirot, E.; Petit, M. (1959), "La mesure des vitesses radiales au prisme objectif - X - 4e liste de vitesses radiales déterminées au prisme objectif à vision directe", Journal des Observateurs, 42: 149, Bibcode:1959JO.....42..149B.
^ abDrilling, J. S.; Schonberner, D. (September 1982), "The hot component of KS Per (HD 30353)", Astronomy and Astrophysics, 113: L22–L23, Bibcode:1982A&A...113L..22D.
^ abcdefghKipper, Tõnu; Klochkova, Valentina G. (2008), "Improved Parameters of the Hydrogen-Deficient Binary Star KS Per", Baltic Astronomy, 17: 195–207, arXiv:0806.2709, Bibcode:2008BaltA..17..195K.
^Heard, John Frederick (1962), "The spectroscopic orbit of Bidelman's peculiar star H.D. 30353", Publications of the David Dunlap Observatory, 2 (9), Toronto, Canada: University of Toronto Press: 269–277, Bibcode:1962PDDO....2..269H.
^Hall, Philip D.; Jeffery, C. (April 2018), "The positive binding energy envelopes of low-mass helium stars", Monthly Notices of the Royal Astronomical Society, 475 (3): 3889–3895, Bibcode:2018MNRAS.475.3889H, doi:10.1093/mnras/sty055.
^Heard, J. F.; Boshko, O. (June 1955), "The orbital elements of the hydrogen-poor spectroscopic binary HD 30353", Astronomical Journal, 60: 162, Bibcode:1955AJ.....60..162H, doi:10.1086/107194.
^Wallerstein, George; et al. (October 1967), "Abundances of the Light Elements in the Hydrogen-Poor Star HD 30353", Astrophysical Journal, 150: 245, Bibcode:1967ApJ...150..245W, doi:10.1086/149326.
^Morrison, K.; Willingale, G. P. H. (October 1987), "The photometric variability of the extremely hydrogen-deficient stars KS Persei and LSII +33 5", Monthly Notices of the Royal Astronomical Society, 228 (4): 819–825, Bibcode:1987MNRAS.228..819M, doi:10.1093/mnras/228.4.819.
Parthasarathy, M.; et al. (April 1990), "The ultraviolet spectrum of the hydrogen-poor binary HD 30353", Astronomy and Astrophysics, 230: 136–144, Bibcode:1990A&A...230..136P.
Margoni, R.; et al. (October 1988), "Investigations on binaries with more massive invisible components. I.The H-deficient system KS Persei", Astronomy and Astrophysics Supplement Series, 75: 157–162, Bibcode:1988A&AS...75..157M.
Nariai, K. (1972), "Deplacement vers le violet de la raie d'absorption H alpha de l'etoile HD 30353 depourvue d'hydrogene", Publications of the Astronomical Society of Japan, 24: 495, Bibcode:1972PASJ...24..495N.
Danziger, I. J.; et al. (October 1967), "On the Absolute Magnitude and Effective Temperature of the Hydrogen-Poor Star HD 30353", Astrophysical Journal, 150: 239, Bibcode:1967ApJ...150..239D, doi:10.1086/149325.
Nariai, K. (1963), "Line blanketing effect on the peculiar star HD 30353", Publications of the Astronomical Society of Japan, 15: 7, Bibcode:1963PASJ...15....7N.
Nariai, K. (1963), "Analysis of the Hydrogen Deficient Star HD 30353", Publications of the Astronomical Society of Japan, 15: 449, Bibcode:1963PASJ...15..449N.
