RR Lyncis

RR Lyncis is a star system in the northern constellation of Lynx, abbreviated RR Lyn. It is an eclipsing binary of the Algol type;[5] one of the closest in the northern sky[10] at an estimated distance of approximately 263 light years based on parallax measurements.[1] The system is faintly visible to the naked eye with a combined apparent visual magnitude of 5.53.[2] During the primary eclipse the brightness drops to 6.03, while it decreases to magnitude 5.90 with the secondary eclipse.[5] The system is drifting closer to the Sun with a radial velocity of −12 km/s.[6]

A light curve for RR Lyncis, plotted from TESS[11]
RR Lyncis
Location of RR Lyncis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Lynx
Right ascension 06h 26m 25.837s[1]
Declination +56° 17′ 06.35″[1]
Apparent magnitude (V) 5.53[2]
Characteristics
Evolutionary stage Main sequence
Spectral type kA3hA7VmF2[3] + F0 V[4]
B−V color index 0.238±0.013[2]
Variable type Detached Algol[5]
Astrometry
Radial velocity (Rv)−12.03±0.04[6] km/s
Proper motion (μ) RA: −26.232 mas/yr[1]
Dec.: +21.881 mas/yr[1]
Parallax (π)12.4161 ± 0.0918 mas[1]
Distance263 ± 2 ly
(80.5 ± 0.6 pc)
Absolute magnitude (MV)1.16[2]
Orbit[7]
Period (P)9.945080±0.000059 d
Semi-major axis (a)29.32±0.04 R☉
Eccentricity (e)0.0793±0.0009
Inclination (i)87.45±0.11°
Periastron epoch (T)2,453,334,634±0.017 HJD
Argument of periastron (ω)
(secondary)		179.4±0.6°
Semi-amplitude (K1)
(primary)		65.65±0.06 km/s
Semi-amplitude (K2)
(secondary)		83.92±0.17 km/s
Details[4]
Primary
Mass1.939±0.007 M☉
Radius2.564±0.019 R☉
Luminosity21.6 L☉
Surface gravity (log g)3.9078±0.0063 cgs
Temperature7,770±200 K
Rotational velocity (v sin i)14.6±1[7] km/s
Age1.08±0.15[7] Gyr
Secondary
Mass1.510±0.003 M☉
Radius1.613±0.013 R☉
Luminosity6.23 L☉
Surface gravity (log g)4.2017±0.0071 cgs
Temperature7,180±200 K
Rotational velocity (v sin i)11.3±2[7] km/s
Other designations
RR Lyn, BD+56°1125, FK5 2491, GC 8281, HD 44691, HIP 30651, HR 2291, SAO 25731,[8] Boss 1607, Groom 1149[9]
Database references
SIMBADdata

This star was found to have a variable radial velocity by W. S. Adams, based on measurements taken in 1911, which suggested it is a spectroscopic binary system. At the time it was identified as Boss 1607 and Groom 1149.[9] Orbital elements for the binary were first published in 1915 by W. E. Harper.[12] In 1931, C. M. Huffer determined Boss 1607 to be an eclipsing binary, based on a light curve generated using photoelectric measurements. This showed a period of 9.9450 days with a magnitude difference of 1.20 between the components.[13] N. G. Roman in 1949 found this to be a metallic-line star and a possible member of the Ursa Major stream.[14]

In 1960, C. and M. Jaschek published a spectral analysis of RR Lyn that showed hydrogen lines for a star of type A7, a K-line of type A3, and metallic lines of type F0 or cooler.[15] Kh. F. Khaliullin and A. I. Khaliullina in 2002 found that the timing of the primary and secondary eclipses underwent quasi-period oscillations. This may be explained by a third body with a mass 90% of the Sun in orbit with the pair. However, as of 2006 the presence of this object has not been confirmed through spectroscopic measurement.[10]

This is a detached double-lined spectroscopic binary with an orbital period of 9.95 days and a small eccentricity. The orbital plane is inclined at an angle of 87.5°, so both stars are seen to eclipse each other once per orbit. The primary component is a slightly-evolved Am star with 1.9 times the mass and 2.6 times the radius of the Sun. The secondary is an F-type main-sequence star with 1.5 times the mass of the Sun and 1.6 times the Sun's radius. The system exhibits pulsation behavior, most of which is attributed to the secondary. The higher frequency modes are Delta Scuti-type pulsations, while the intermediate frequencies are of the Gamma Doradus type. Lower frequency pulsations may be tidally-excited.[4] The system is about one billion years old.[7]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  2. 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.
  3. Levato, H.; Abt, H. A. (August 1978), "Spectral types in the Ursa Major stream", Publications of the Astronomical Society of the Pacific, 90: 429−433, Bibcode:1978PASP...90..429L, doi:10.1086/130352.
  4. Southworth, J. (December 2021), "Rediscussion of eclipsing binaries. Paper 7: Delta Scuti, Gamma Doradus, and tidally-perturbed pulsations in RR Lyncis", The Observatory, 141: 282–295, arXiv:2109.10196, Bibcode:2021Obs...141..282S.
  5. 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.
  6. Pourbaix, D.; et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy and Astrophysics, 424 (2): 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
  7. Tomkin, Jocelyn; Fekel, Francis C. (May 2006), "New Precision Orbits of Bright Double-Lined Spectroscopic Binaries. I. RR Lyncis, 12 Bootis, and HR 6169", The Astronomical Journal, 131 (5): 2652–2663, arXiv:astro-ph/0601716, Bibcode:2006AJ....131.2652T, doi:10.1086/501349, S2CID 119522198.
  8. "RR Lyn". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2022-07-18.
  9. Adams, W. S. (April 1912), "The three-prism stellar spectrograph of the Mount Wilson Solar Observatory.", Astrophysical Journal, 35: 163–182, Bibcode:1912ApJ....35..163A, doi:10.1086/141924.
  10. Bensch, Katarzyna; et al. (December 2014), "New spectroscopy of multiple stars RR Lyncis and HT Virginis", Information Bulletin on Variable Stars, 6121: 1, Bibcode:2014IBVS.6121....1B.
  11. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  12. Popper, Daniel M. (November 1971), "Some Double-Lined Eclipsing Binaries with Metallic-Line Spectra", Astrophysical Journal, 169: 549, Bibcode:1971ApJ...169..549P, doi:10.1086/151173.
  13. Huffer, C. M. (1931), Fox, Philip; Stebbins, Joel (eds.), "Report on photo-electric studies", Publications of the American Astronomical Society, AAS, 6: 365, Bibcode:1931PAAS....6R.365H.
  14. Roman, Nancy Grace (September 1949), "The Ursa Major Group", Astrophysical Journal, 110: 205, Bibcode:1949ApJ...110..205R, doi:10.1086/145199.
  15. Jaschek, M.; Jaschek, C. (1960), "A Search for Families among Metallic-Line Stars", Zeitschrift für Astrophysik, 50: 155, Bibcode:1960ZA.....50..155J.

Further reading
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