Astronomy:CX Draconis
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Short description: Binary star system in the constellation Draco
 Light curves for CX Draconis. The main plot, from Hipparcos data,[1] shows the long-term variability. The inset plot, from TESS data,[2] shows how the brightness changes of short timescales. | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Draco |
| Right ascension | 18h 46m 43.089s[3] |
| Declination | +52° 59′ 16.65″[3] |
| Apparent magnitude (V) | 5.68 to 5.99[4] |
| Characteristics | |
| Spectral type | B2.5 V + F5 III[5] |
| Variable type | γ Cas + rotating ellipsoidal[4] |
| Astrometry | |
| Radial velocity (Rv) | −2.1±2.3[6] km/s |
| Proper motion (μ) | RA: 10.965[3] mas/yr Dec.: −4.920[3] mas/yr |
| Parallax (π) | 2.8262 ± 0.0587[3] mas |
| Distance | 1,150 ± 20 ly (354 ± 7 pc) |
| Orbit[7] | |
| Period (P) | 6.695957±0.000043 d |
| Semi-major axis (a) | ≥ 3.253 Gm[8] |
| Eccentricity (e) | 0.052±0.006 |
| Inclination (i) | 52 to 55° |
| Periastron epoch (T) | 2,442,549.48±0.24 HJD |
| Argument of periastron (ω) (secondary) | 267.9±6.4° |
| Semi-amplitude (K1) (primary) | 33.66±0.86 km/s |
| Semi-amplitude (K2) (secondary) | 145.92±0.82 km/s |
| Details | |
| Primary | |
| Mass | 7.3[9] M☉ |
| Surface gravity (log g) | 3.71±0.27[10] cgs |
| Temperature | 19,580±640[10] K |
| Rotational velocity (v sin i) | 163±10[10] km/s |
| Secondary | |
| Mass | ~1.7[9] M☉ |
| Temperature | 6,500[11] K |
| Rotational velocity (v sin i) | ~65[11] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
CX Draconis is an interacting binary star system in the northern constellation of Draco, abbreviated CX Dra. It has the designation HD 174237 in the Henry Draper Catalogue; CX Draconis is the variable star designation. This is a double-lined spectroscopic binary system with a near circular orbit.[7] The brightness of the system undergoes long-term irregular fluctuations,[11] ranging from an apparent visual magnitude of 5.68 down to 5.99.[4] Based on parallax measurements, it is located at a distance of approximately 1,150 light years from the Sun.[3]
In 1921, this target was found to have a varying radial velocity by J. S. Plaskett and associates.[13][14] It was shown to be a Be star by O. C. Mohler in 1940,[15] and in 1965 M. Lacoarret studied variations in the hydrogen alpha emission profiles from the target. This system was discovered to be a photometric variable by P. Merlin in 1975.[14] P. Koubský measured the radial velocity variations in 1976,[16] and in 1978 published orbital elements for this binary system with a period of 6.696 days.[17] He found that the variation in emission lines matched the time scale of the orbit, indicating that this is an interacting binary.[11]
Using observations from the Einstein Observatory, in 1984 this system was shown to be an X-ray source by E. F. Guinan and associates. This emission may be coming from the cooler secondary that is phase-locked with the primary and is magnetically active due to rapid rotation.[18] In 1992, J. Horn and associates determined that the secondary component is an evolved F-type giant star. Evidence suggests this star is overflowing its Roche lobe with gas streaming toward the primary.[11]
Models indicate that the main source of the H-alpha emission is located mid-way between the two stars, with other emission lines originating from an accretion disk orbiting the primary. The circumstellar environment is changing in cycles lasting hundreds of days.[7] Infrared emission to the northeast of the system suggests it may be undergoing systematic mass loss.[19]
References
- ↑ EAS (1997), "The HIPPARCOS and TYCHO catalogues", Astrometric and Photometric Star Catalogues Derived from the ESA Hipparcos Space Astrometry Mission, ESA SP Series (Noordwijk, Netherlands: ESA Publications Division) 1200, ISBN 9290923997, Bibcode: 1997ESASP1200.....E, https://cdsarc.cds.unistra.fr/viz-bin/ftp-index?/ftp/cats/more/HIP/cdroms/cats, retrieved 15 October 2022.
- ↑ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html, retrieved 8 December 2021.
- ↑ 3.0 3.1 3.2 3.3 3.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 4.0 4.1 4.2 Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
- ↑ Berdyugin, A.; Piirola, V. (October 2002), "Polarization variability in the interacting Be binary CX Draconis", Astronomy and Astrophysics 394: 181–186, doi:10.1051/0004-6361:20021109, Bibcode: 2002A&A...394..181B.
- ↑ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G.
- ↑ 7.0 7.1 7.2 Richards, Mercedes T.; Koubský, Pavel; Šimon, Vojtěch; Peters, Geraldine J.; Hirata, Ryuko; Škoda, Petr; Masuda, Seiji (March 2000), "A Multiwavelength Study of Spectral Variations in the CX Draconis Binary", The Astrophysical Journal 531 (2): 1003–1027, doi:10.1086/308491, Bibcode: 2000ApJ...531.1003R.
- ↑ Abt, Helmut A.; Gomez, Ana E.; Levy, Saul G. (October 1990), "The Frequency and Formation Mechanism of B2--B5 Main-Sequence Binaries", Astrophysical Journal Supplement 74: 551, doi:10.1086/191508, Bibcode: 1990ApJS...74..551A.
- ↑ 9.0 9.1 Harmanec, P.; Koubský, P.; Nemravová, J.; Royer, F.; Briot, D.; North, P.; Lampens, P.; Frémat, Y. et al. (January 2015), "Properties and nature of Be stars 30. Reliable physical properties of a semi-detached B9.5e+G8III binary BR CMi = HD 61273 compared to those of other well studied semi-detached emission-line binaries", Astronomy and Astrophysics 573, doi:10.1051/0004-6361/201424640, A107, Bibcode: 2015A&A...573A.107H.
- ↑ 10.0 10.1 10.2 Zorec, J. et al. (November 2016), "Critical study of the distribution of rotational velocities of Be stars. I. Deconvolution methods, effects due to gravity darkening, macroturbulence, and binarity", Astronomy & Astrophysics 595: 26, doi:10.1051/0004-6361/201628760, Bibcode: 2016A&A...595A.132Z, http://sedici.unlp.edu.ar/bitstream/handle/10915/85970/Documento_completo.pdf?sequence=1.
- ↑ 11.0 11.1 11.2 11.3 11.4 Horn, J.; Hubert, A. M.; Hubert, H.; Koubsky, P.; Bailloux, N. (June 1992), "CX Draconis : the orbit parameters for both components", Astronomy and Astrophysics 259: L5–L8, Bibcode: 1992A&A...259L...5H.
- ↑ "CX Dra". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=CX+Dra.
- ↑ Plaskett, J. S.; Harper, W. E.; Young, R. K.; Plaskett, H. H. (1921), "Eighty-eight spectroscopic binaries", Publications of the Dominion Astrophysical Observatory Victoria 1: 287–306, Bibcode: 1921PDAO....1..287P.
- ↑ 14.0 14.1 Merlin, P. (February 1975), "Variations photométriques de l'étoile B à émission HD 174237" (in Fr), Astronomy and Astrophysics 39: 139–141, Bibcode: 1975A&A....39..139M.
- ↑ Mohler, Orren C. (September 1940), "Six New BE Stars", Astrophysical Journal 92: 315, doi:10.1086/144221, Bibcode: 1940ApJ....92..315M.
- ↑ Koubský, P. (October 1976), "HD 174237 (MWC 608)", Information Bulletin on Variable Stars 1188 (1): 1, Bibcode: 1976IBVS.1188....1K.
- ↑ Koubský, P. (1978), "Properties and Nature of Be and Shell Stars. 9. Periodic Radial-velocity Changes of HD 174237", Bulletin of the Astronomical Institute of Czechoslovakia 29: 288, Bibcode: 1978BAICz..29..288K.
- ↑ Guinan, E. F.; Koch, R. H.; Plavec, M. J. (July 1984), "Einstein observations of selected close binaries and shell stars", Astrophysical Journal 282: 667–674, doi:10.1086/162246, Bibcode: 1984ApJ...282..667G.
- ↑ Mayer, A.; Deschamps, R.; Jorissen, A. (March 2016), "Search for systemic mass loss in Algols with bow shocks", Astronomy & Astrophysics 587: A30, doi:10.1051/0004-6361/201526623, A30, Bibcode: 2016A&A...587A..30M.
Further reading
- Pustylnik, I.; Kalv, P.; Harvig, V.; Aas, T. (2007), "On Quasi-Periodic Intrinsic Light Variability in a Close Spectroscopic Binary CX DRA", Odessa Astronomical Publications 20: 186, Bibcode: 2007OAP....20..186P.
- Berdyugin, A.; Piirola, V. (October 2002), "Polarization variability in the interacting Be binary CX Draconis", Astronomy and Astrophysics 394: 181–186, doi:10.1051/0004-6361:20021109, Bibcode: 2002A&A...394..181B.
- Skoda, Petr; Koubsky, Pavel (2000), Smith, M. A.; Henrichs, H. F.; Fabregat, J., eds., "IUE Spectra of Be Star CX Dra: Evidence for Winds", The Be Phenomenon in Early-Type Stars, IAU Colloquium 175, ASP Conference Series 214: p. 573, Bibcode: 2000ASPC..214..573S, https://www.cambridge.org/core/services/aop-cambridge-core/content/view/C43B07F8914B2D2B299445329B6398F7/S0252921100056542a.pdf, retrieved 2023-02-15.
- Iwamatsu, H.; Hirata, R.; Masuda, S. (2000), Smith, Myron A.; Henrichs, Huib F., eds., "Origin of Circumstellar Matter in the Spectroscopic Binary CX Dra", The Be Phenomenon in Early-Type Stars, IAU Colloquium 175, ASP Conference Proceedings (Astronomical Society of the Pacific) 214: p. 701, ISBN 1-58381-045-5, Bibcode: 2000ASPC..214..701I.
- Koubský, P.; Richards, M. T.; Šimon, V. (February 1998), Dusek, J.; Zejda, M., eds., "Circumstellar Matter in the Interacting Binary CX Draconis", Proceedings of the 29th Conference on Variable Star Research. 7th - 9th November 1997. Brno, Czech Republic: p. 64, ISBN 80-85882-09-4, Bibcode: 1998stel.conf...64K.
- Koubsky, P.; Harmanec, P.; Bozic, H.; Rercy, J. R.; Ziznovsky, J.; Huang, L.; Richards, M. T.; Hadrava, P. et al. (1998), "Spectroscopy and Photometry of the Interacting Binary CX Draconis - Evidence for Circumstellar Mater", Hvar Observatory Bulletin 22 (1): 17–36, Bibcode: 1998HvaOB..22...17K.
- Simon, V. (April 1996), "The interacting binary CX Draconis: new orbital elements and evidence for mass transfer.", Astronomy and Astrophysics 308: 799–808, Bibcode: 1996A&A...308..799S.
- Koubský, P.; Horn, J.; Harmanec, P.; Peters, G. J.; Polidan, R. S. (1990), İbanoğlu, C, ed., "Interacting Binary CX Draconis", Active Close Binaries, NATO ASI Series (Dordrecht: Springer) 319: pp. 237–238, doi:10.1007/978-94-009-0679-2_18, ISBN 978-94-010-6790-4.
- Magalashvili, N. L.; Kumsishvili, Ya. I. (1986), "Photometric observations of the emission B star CX Dra (HD 174237)", Byulleten Abastumanskaya Astrofizicheskaya Observatoriya 61: 79–82, Bibcode: 1986AbaOB..61...79M.
- Harmanec, P.; Horn, J.; Koubsky, P.; Ziznovsky, J. (March 1981), "Call for Systematic Photoelectric Observations of CX Dra", Information Bulletin on Variable Stars 1931: 1, Bibcode: 1981IBVS.1931....1H.
- Koubský, P.; Harmanec, P.; Horn, J.; Jerzykiewicz, M.; Papoušek, J.; Kříž, S.; Pavlovski, K.; Ždárský, F. (1980), "Properties and Nature of Be and Shell Stars. 10. Light and Colour Variations of CX Dra", Bulletin of the Astronomical Institute of Czechoslovakia 31 (2): 75–84, Bibcode: 1980BAICz..31...75K.
- Koubský, P.; Harmanec, P.; Horn, J.; Jerzykiewicz, M.; Kríz, S.; Pavlovski, K.; Zdárský, F. (1980), "UBV photometry of CX Cra. Search for rapid variations", Acta Universitatis Carolinae, Mathematica et Physica 21 (2): 33–54, Bibcode: 1980AcMPh..21...33K, https://dml.cz/bitstream/handle/10338.dmlcz/142453/ActaCarolinae_021-1980-2_6.pdf, retrieved 2023-02-15.
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