4 Draconis

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4 Draconis
CQDraLightCurve.png
Light curves for CQ Draconis, adapted from Skopal et al. (1992) [1] The brightening seen (most clearly in the ultraviolet) after June 1990 occurred shortly after the periastron passage. [2]
Observation data
Epoch J2000.0        Equinox J2000.0
Constellation Draco
Right ascension 12h 30m 06.66200s [3]
Declination +69° 12′ 03.9742″ [3]
Apparent magnitude  (V)4.90 - 5.12 [4]
Characteristics
Spectral type M3+ IIIa [5]
Variable type Z Andromedae [4]
Astrometry
Radial velocity (Rv)−15 [6]  km/s
Proper motion (μ)RA: −57.311±0.214 [3]   mas/yr
Dec.: −50.365±0.219 [3]   mas/yr
Parallax (π)5.7233 ± 0.1880  mas [3]
Distance 570 ± 20  ly
(175 ± 6  pc)
Absolute magnitude  (MV)−1.37 [7]
Orbit [8]
Primary4 Draconis A (red giant)
Companion4 Draconis B
Period (P)1,703±3  d
Semi-major axis (a)82±4  Gm ( a⋅sin(i) )
Eccentricity (e)0.30±0.05
Periastron epoch (T)2442868.5
Argument of periastron (ω)
(primary)		244±9°
Semi-amplitude (K1)
(primary)		3.67±0.19 km/s
Details
red giant
Mass 1.64±0.2 [9]   M☉
Radius 111.0+9.30
−11.2 [9]   R☉
Luminosity 2,122±419 [9]   L☉
Surface gravity (log g)1.24 [9]   cgs
Temperature 3,718±69 [9]   K
Age 1.97±0.57 [9]   Gyr
white dwarf
Mass ~0.8 [10]   M☉
Temperature 20,000±3,000 [10]   K
Other designations
CQ Dra, HD 108907, HR  4765, HIP  60998, SAO  15816 [11]
Database references
SIMBAD data

4 Draconis, also known as HR 4765 and CQ Draconis, is a star about 570 light years from the Earth, in the constellation Draco. [3] It is a 5th magnitude star, so it will be faintly visible to the naked eye of an observer far from city lights. [3] It is a variable star, whose brightness varies slightly from 4.90 to 5.12 over a period of 4.66 years. [4]

In 1967, Olin Eggen discovered that 4 Draconis is a variable star, during a multicolor photometric survey of red stars. [12] In 1973 it was given the variable star designation CQ Draconis. [13]

Until the year 1985, 4 Draconis was thought to be a normal red giant star. In 1985, Dieter Reimers announced that the International Ultraviolet Explorer had detected a hot companion to the red giant, which itself appeared to be a binary cataclysmic variable star, making the complete system a triple star. [14] However a 2003 study by Peter Wheatley et al., who examined ROSAT X-ray data for the star, concluded that the hot companion was more apt to be a single white dwarf, rather than a binary, and that the white dwarf is accreting material from the red giant. [15] There does not yet appear to be a consensus about the multiplicity; some later studies consider 4 Draconis to be a binary, [16] [17] and some a triple. [18] [10]

In 1987, Alexander Brown announced that 6 cm wavelength radio emission had been detected by the Very Large Array. The strength of the radio emission was variable on a timescale of weeks to months. [19]

It is possible that an outburst of 4 Draconis was the "guest star" reported by Chinese astronomers in the year 369 CE, in the constellation Zigong. [20]

Related Research Articles

<span class="mw-page-title-main">Beta Draconis</span> Binary star system in the constellation Draco

Beta Draconis, a name Latinized from β Draconis, is a binary star system and the third-brightest star in the northern circumpolar constellation of Draco. The two components are designated Beta Draconis A and B respectively. With a combined apparent visual magnitude of 2.79, it is bright enough to be easily seen with the naked eye. Based upon parallax measurements from the Hipparcos astrometry satellite, it lies at a distance of about 380 light-years from the Sun. The system is drifting closer with a radial velocity of −21 km/s.

<span class="mw-page-title-main">Nu Draconis</span> Star system in the constellation Draco

Nu Draconis is a double star in the constellation Draco. The respective components are designated 𝜈1 Draconis and 𝜈2 Draconis. The second component is a spectroscopic binary star system.

<span class="mw-page-title-main">Lambda Draconis</span> Star in the constellation Draco

Lambda Draconis, also named Giausar, is a solitary, orange-red star in the northern circumpolar constellation of Draco. It is visible to the naked eye with an apparent visual magnitude of +3.85. Based upon an annual parallax shift of 9.79 mas as seen from the Earth, the star is located around 333 light years from the Sun.

<span class="mw-page-title-main">Kappa Draconis</span> Star in the constellation Draco

Kappa Draconis, Latinized from κ Draconis, is a blue giant star located in the northern circumpolar constellation of Draco. At an apparent magnitude of 3.88, it is barely visible to the naked eye when artificial lighting from cities is present. Nevertheless, it is a powerful star, approximately five time as massive as the Sun. It is about 460 light-years away, and is 1,400 times brighter than the Sun.

Psi<sup>1</sup> Draconis Star in the constellation Draco

Psi1 Draconis, also designated 31 Draconis, is a triple star system in the northern constellation of Draco. The system is fairly close, and is located about 75 light-years from the Sun, based on its parallax.

<span class="mw-page-title-main">Chi Draconis</span> Star in the constellation of Draco

Chi Draconis is a magnitude 3.6 binary star in the constellation Draco. It also has the Flamsteed designation 44 Draconis. At a distance of 27 light years, it is one of the forty or so closest stars.

<span class="mw-page-title-main">Symbiotic binary</span> Class of astronomical objects

A symbiotic binary is a type of binary star system, often simply called a symbiotic star. They usually contain a white dwarf with a companion red giant. The cool giant star loses material via Roche lobe overflow or through its stellar wind, which flows onto the hot compact star, usually via an accretion disk.

<span class="mw-page-title-main">Omicron Draconis</span> Variable star in the constellation Draco

Omicron Draconis is a giant star in the constellation Draco located 322.93 light years from the Earth. Its path in the night sky is circumpolar for latitudes greater than 31o north, meaning the star never rises or sets when viewed in the night sky.

<span class="mw-page-title-main">CM Draconis</span> Star in the constellation Draco

CM Draconis is an eclipsing binary star system 48.5 light-years away in the constellation of Draco. The system consists of two nearly identical red dwarf stars that orbit each other with a period of 1.268 days and a separation of 2.6 million kilometres. Along with two stars in the triple system KOI-126, the stars in CM Draconis are among the lightest stars with precisely measured masses and radii. Consequently, the system plays an important role in testing stellar structure models for very low mass stars. These comparisons find that models underpredict the stellar radii by approximately 5%. This is attributed to consequences of the stars' strong magnetic activity.

<span class="mw-page-title-main">AG Draconis</span> Star in the constellation Draco

AG Draconis is a binary star system in the northern constellation of Draco. It consists of a giant star and a white dwarf that revolve around each other every 550 days.

A luminous supersoft X-ray source is an astronomical source that emits only low energy X-rays. Soft X-rays have energies in the 0.09 to 2.5 keV range, whereas hard X-rays are in the 1–20 keV range. SSSs emit few or no photons with energies above 1 keV, and most have effective temperature below 100 eV. This means that the radiation they emit is highly ionizing and is readily absorbed by the interstellar medium. Most SSSs within our own galaxy are hidden by interstellar absorption in the galactic disk. They are readily evident in external galaxies, with ~10 found in the Magellanic Clouds and at least 15 seen in M31.

<span class="mw-page-title-main">Theta Draconis</span> Binary star system in the constellation Draco

Theta Draconis, a name Latinized from θ Draconis, is a binary star system in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye at night with an apparent visual magnitude of 4.12. Parallax measurements place it at an estimated distance of 68.6 light-years from the Sun, and it is drifting closer with a radial velocity of −8 km/s. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.464″ per year. O. J. Eggen included this star as a member of the NGC 1901 supercluster based on its space motion.

<span class="mw-page-title-main">Phi Draconis</span> Star in the constellation Draco

Phi Draconis is a fourth-magnitude variable star in the constellation Draco. It has the Flamsteed designation 43 Draconis. It is also a triple star system where the brightest component is a chemically peculiar Ap star.

Upsilon Draconis is a binary star system in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye with an apparent visual magnitude of 4.83. Based upon an annual parallax shift of 9.48 mas as measured from Earth, it is located around 340 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.02 due to interstellar dust.

<span class="mw-page-title-main">CH Cygni</span> Variable star in the Cygnus constellation

CH Cygni is a red giant, variable, symbiotic binary in the constellation Cygnus. It is the nearest symbiotic star to Earth, and one of the brightest, making it an ideal candidate for study.

<span class="mw-page-title-main">EG Andromedae</span> Binary star system in the constellation Andromeda

EG Andromedae is a symbiotic binary in the constellation Andromeda. Its apparent visual magnitude varies between 6.97 and 7.80.

<span class="mw-page-title-main">HM Sagittae</span> Symbiotic nova in the constellation of Sagitta

HM Sagittae is a dusty-type symbiotic nova in the northern constellation of Sagitta. It was discovered by O. D. Dokuchaeva and colleagues in 1975 when it increased in brightness by six magnitudes. The object displays an emission line spectrum similar to a planetary nebula and was detected in the radio band in 1977. Unlike a classical nova, the optical brightness of this system did not rapidly decrease with time, although it showed some variation. It displays activity in every band of the electromagnetic spectrum from X-ray to radio.

<span class="mw-page-title-main">SU Cygni</span> Variable star system in the constellation Cygnus

SU Cygni is a triple star system in the northern constellation of Cygnus, abbreviated SU Cyg. The primary component of the system is a classical Cepheid variable with a period of 3.8455473 days. The changing luminosity of this star causes the system to vary in brightness from a peak apparent visual magnitude of 6.44 down to magnitude 7.22 over the course of its cycle. The distance to this system is approximately 3,200 light years based on parallax measurements. It is a member of the Turner 9 open cluster of stars.

<span class="mw-page-title-main">CX Draconis</span> Binary star system in the constellation Draco

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. The brightness of the system undergoes long-term irregular fluctuations, ranging from an apparent visual magnitude of 5.68 down to 5.99. Based on parallax measurements, it is located at a distance of approximately 1,150 light years from the Sun.

<span class="mw-page-title-main">DO Draconis/YY Draconis</span> Binary star in the constellation of Draco

YY Draconis and DO Draconis are separate identifiers for what is likely the same cataclysmic variable system in the northern constellation of Draco, abbreviated YY Dra and DO Dra, respectively. The DO Dra binary star system is classified as a U Geminorum variable that ranges in luminosity from an apparent visual magnitude of 10.0 down to 15.1. It is located at a distance of approximately 639 light years from the Sun.

References

  1. ↑ Skopal, A.; Hric, L.; Urban, Z.; Pigulski, A.; Blanco, C.; Papousek, J.; Hanzl, D.; Agerer, F.; Niarchos, P.; Rovithis-Livaniou, H.; Rovithis, P.; Tsvetkova, K.; Semkov, E.; Velic, Z.; Michalek, F.; Komacka, L.; Schweitzer, E.; Korth, S. (July 1992). "Photometry of symbiotic stars - an international campaign. III. Z And, EG And, R Aqr, UV Aur, TX CVn, T CrB, BF Cyg, CH Cyg, CI Cyg, V 1016 Cyg, V 1329 Cyg, AG Dra, CQ DRA (4 Dra), YY Her, V 443 Her, SS Lep, RS Oph, AG Peg, AX Per, HM Sge, FG Ser (AS 296), PU Vul". Contributions of the Astronomical Observatory Skalnate Pleso. 22: 131–172. Bibcode:1992CoSka..22..131S . Retrieved 26 February 2023.
  2. ↑ Hric, L.; Urban, Z. (November 1991). "The Symbiotic-Like/Cataclysmic Triple System 4 Dra (= CQ Dra): Detection of a Post-Periastron Passage Brightening" (PDF). Information Bulletin on Variable Stars. 3683: 1. Bibcode:1991IBVS.3683....1H . Retrieved 28 February 2023.
  3. 1 2 3 4 5 6 7 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 at VizieR.
  4. 1 2 3 "CQ Dra". The International Variable Star Index. AAVSO. Retrieved 26 February 2023.
  5. ↑ Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". The Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
  6. ↑ Famaey, B.; Pourbaix, D.; Frankowski, A.; van Eck, S.; Mayor, M.; Udry, S.; Jorissen, A. (May 2009). "Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations". Astronomy and Astrophysics. 498 (2): 627–640. arXiv: 0901.0934 . Bibcode:2009A&A...498..627F. doi: 10.1051/0004-6361/200810698 .
  7. ↑ 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.
  8. ↑ Reimers, D.; Griffin, R. F.; Brown, A. (March 1988). "4 Draconis : a unique triple system containing an M3 giant and a cataclysmic binary". Astronomy and Astrophysics. 193: 180–184. Bibcode:1988A&A...193..180R . Retrieved 28 February 2023.
  9. 1 2 3 4 5 6 Baines, Ellyn K.; Armstrong, J. Thomas; Schmitt, Henrique R.; Zavala, R. T.; Benson, James A.; Hutter, Donald J.; Tycner, Christopher; van Belle, Gerard T. (2017). "Fundamental parameters of 87 stars from the Navy Precision Optical Interferometer". The Astronomical Journal. 155 (1): 16. arXiv: 1712.08109 . Bibcode:2018AJ....155...30B. doi: 10.3847/1538-3881/aa9d8b . S2CID   119427037.
  10. 1 2 3 Sion, Edward M.; Godon, Patrick; Mikolajewska, Joanna; Sabra, Bassem; Kolobow, Craig (April 2017). "FUSE Spectroscopy of the Accreting Hot Components in Symbiotic Variables". The Astronomical Journal. 153 (4): 160. arXiv: 1702.07341 . Bibcode:2017AJ....153..160S. doi: 10.3847/1538-3881/aa62a9 . PMC   5810147 . PMID   29456255.
  11. ↑ "4 Dra -- Spectroscopic Binary". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2023-02-26.
  12. ↑ Eggen, O. J. (September 1967). "Narrow and broad band photometry of red stars : I. Northern giants". Astrophysical Journal Supplement Series. 14: 307–358. Bibcode:1967ApJS...14..307E. doi: 10.1086/190158 . Retrieved 27 February 2023.
  13. ↑ Kukarkin, B. V.; Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (October 1973). "59th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 834: 1. Bibcode:1973IBVS..834....1K . Retrieved 27 February 2023.
  14. ↑ Reimers, D. (January 1985). "Discovery of a cataclysmic variable type companion of the M3 III giant 4 DRA with IUE". Astronomy and Astrophysics. 142: L16–L18. Bibcode:1985A&A...142L..16R . Retrieved 27 February 2023.
  15. ↑ Wheatley, Peter J.; Mukai, Koji; de Martino, Domitilla (December 2003). "X-ray observations of 4 Draconis: symbiotic binary or cataclysmic triple?". Monthly Notices of the Royal Astronomical Society. 346 (3): 855–860. arXiv: astro-ph/0309410 . Bibcode:2003MNRAS.346..855W. doi: 10.1111/j.1365-2966.2003.07149.x .
  16. ↑ Skopal, A. (August 2005). "Accretion-powered symbiotic binaries: EG And and CQ Dra" (PDF). The Astrophysics of Cataclysmic Variables and Related Objects, Proceedings of ASP Conference. 330: 463–464. Bibcode:2005ASPC..330..463S . Retrieved 28 February 2023.
  17. ↑ Nuñez, N. E.; Nelson, T.; Mukai, K.; Sokoloski, J. L.; Luna, G. J. M. (June 2016). "Symbiotic Stars in X-Rays. III. Suzaku Observations". The Astrophysical Journal. 824 (1): 23. arXiv: 1604.05980 . Bibcode:2016ApJ...824...23N. doi: 10.3847/0004-637X/824/1/23 .
  18. ↑ Di Stefano, R. (April 2020). "Mass from a third star: transformations of close compact-object binaries within hierarchical triples". Monthly Notices of the Royal Astronomical Society. 493 (2): 1855–1873. arXiv: 1805.09338 . Bibcode:2020MNRAS.493.1855D. doi: 10.1093/mnras/staa220 . Retrieved 28 February 2023.
  19. ↑ Brown, Alexander (January 1987). "Variable Radio Emission from the 4 Draconis System". Astrophysical Journal Letters. 312: L51–L53. Bibcode:1987ApJ...312L..51B. doi:10.1086/184818 . Retrieved 27 February 2023.
  20. ↑ Hoffmann, Susanne M.; Vogt, Nikolaus (September 2020). "A search for the modern counterparts of the Far Eastern guest stars 369 CE, 386 CE and 393 CE". Monthly Notices of the Royal Astronomical Society. 497 (2): 1419–1433. arXiv: 2007.01013 . Bibcode:2020MNRAS.497.1419H. doi: 10.1093/mnras/staa1970 .
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