V1054 Ophiuchi

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Coordinates: Sky map 16h 55m 32.0s, −08° 21′ 30″ V1054 Ophiuchi, together with the star Gliese 643, is a nearby quintuple star system, located in constellation Ophiuchus at 21.05 light-years. It consists of five stars, all of which are red dwarfs.

Overview[edit]

V1054 Ophiuchi/Gliese 643 has the largest number of stars of all star systems, located within 10 pc from Earth.[1] It is also the nearest quintuple star system[2] (the next nearest star systems with at least five stars are GJ 2069 (quintuple)[1] at 41.8 light-years, and Castor[2] (sextuple) at 51.6 light-years), and only quintuple star system within 10 pc.[1][3]

The system consists of three widely separated parts:

  • close triple subsystem V1054 Ophiuchi A-Bab (including very close binary subsystem V1054 Ophiuchi Bab)
  • Gliese 643
  • V1054 Ophiuchi C (vB 8)

Hierarchy of the system is following:[2]

V1054 Ophiuchi/Gliese 643
V1054 Ophiuchi/Gliese 643 (without V1054 Ophiuchi C)
V1054 Ophiuchi A-Bab
V1054 Ophiuchi Bab

V1054 Ophiuchi Ba



V1054 Ophiuchi Bb




V1054 Ophiuchi A




Gliese 643




V1054 Ophiuchi C (vB 8)



System's five components are:

Star Mass, M Spectral
class
Absolute
magnitude (MV)
Apparent
magnitude (V)
V1054 Ophiuchi A 0.4155 ± 0.0057[1] M3 V[1] 10.69 ± 0.02[2] 9.74[2][note 1]
V1054 Ophiuchi Ba 0.3466 ± 0.0047[1] M4 Ve[note 2] 11.29 ± 0.05[2] 10.34[2][note 1]
V1054 Ophiuchi Bb 0.3143 ± 0.0040[1] M4 Ve[note 2] 11.79 ± 0.05[2] 10.84[2][note 1]
Gliese 643 0.19[2] M3.5 V[1] 12.69[2] 11.74[2]
V1054 Ophiuchi C 0.08[2] M7.0 V[2] 17.75[2] 16.80[2]

The brightest and most massive of this five stars is V1054 Ophiuchi A. Close binary subsystem V1054 Ophiuchi B is more massive than V1054 Ophiuchi A, however, its total visual magnitude is 0.1 mag fainter than V1054 Ophiuchi A's visual magnitude.[2]

Total apparent magnitude of V1054 Ophiuchi A-Bab triple subsystem is 9.02.[2][4]

Despite V1054 Ophiuchi/Gliese 643 consists of small low-mass stars, system's total mass, due large number of components, exceeds Solar mass,[2] (it is about 1.35 M).

Distance[edit]

Currently, the most accurate distance estimate of V1054 Ophiuchi/Gliese 643 (apart from weighted mean distance, see below) is trigonometric parallax of V1054 Ophiuchi AB from YPC (Yale Parallax Catalog), 4th edition, published in 1995 (van Altena, Lee & Hoffleit):[5] 154.8 ± 0.6 mas, corresponding to a distance 6.460 ± 0.025 pc, or 21.07 ± 0.08 ly.

V1054 Ophiuchi/Gliese 643 distance estimates

V1054 Ophiuchi A-Bab:

Source Paper Parallax, mas Distance, pc Distance, ly Ref.
Woolley Woolley et al. 1970 156 ± 4 6.41 ± 0.17 20.9 ± 0.6 [6]
GJ, 3rd version Gliese & Jahreiß 1991 153.9 ± 2.6 6.50 ± 0.11 21.19 ± 0.36 [7]
YPC, 4th edition van Altena et al. 1995 154.8 ± 0.6 6.460 ± 0.025 21.07 ± 0.08 [5]
Hipparcos Perryman 1997 174.23 ± 3.90 5.74 ± 0.13 18.7 ± 0.4 [4]
Soederhjelm Soederhjelm 1999 155.63 ± 1.81 6.43 ± 0.08 20.96 ± 0.25 [8]
Hipparcos2 van Leeuwen 2007 161.41 ± 5.64 6.20 ± 0.22 20.21 ± 0.73 [9]

Gliese 643:

Source Paper Parallax, mas Distance, pc Distance, ly Ref.
Woolley Woolley et al. 1970 169 ± 5 5.92 ± 0.18 19.3 ± 0.6 [6]
GJ, 3rd version Gliese & Jahreiß 1991 171.9 ± 7.3 5.82 ± 0.26 19.0 ± 0.8 [7]
YPC, 4th edition van Altena et al. 1995 169.8 ± 6.6 5.89 ± 0.24 19.2 ± 0.8 [5]
Hipparcos Perryman 1997 153.96 ± 4.04 6.50 ± 0.18 21.2 ± 0.6 [4]
Hipparcos2 van Leeuwen 2007 148.92 ± 4.00 6.72 ± 0.19 21.9 ± 0.6 [9]

V1054 Ophiuchi C (vB 8):

Source Paper Parallax, mas Distance, pc Distance, ly Ref.
CTIOPI 1.5 m TSN 14 (Costa et al. 2005) 155.43 ± 1.33 6.43 ± 0.06 20.98 ± 0.18 [10]

The most accurate estimate is marked in bold.

Weighted mean distance[edit]

Weighted mean parallax,[11] considering YPC (V1054 Ophiuchi A-Bab and Gliese 643), Hipparcos (Soederhjelm — V1054 Ophiuchi A-Bab and van Leeuwen — Gliese 643) and CTIOPI (V1054 Ophiuchi C) data, is 154.96 ± 0.52 mas,[12] corresponding to a distance 6.453 ± 0.022 pc, or 21.05 ± 0.07 ly.

V1054 Ophiuchi A-Bab (inner triple subsystem)[edit]

V1054 Ophiuchi A-Bab is a close spectroscopic triple subsystem, consisting of brighter component V1054 Ophiuchi A and more massive binary subsystem V1054 Ophiuchi Bab, orbiting each other with period 627 days,[1][2] or 1.72 years.[2] V1054 Ophiuchi Bab components are orbiting each other with period 2.9655 days.[1][2] Both outer and inner orbits are nearly circular and, probably, coplanar[1][2] (in keeping with a general tendency of close triple systems).[1]

V1054 Ophiuchi A-Bab pair is also visually resolved (for nearly 50 years it was the shortest-period resolved by visual means binary, since its binarity was discovered by G. P. Kuiper in 1934),[2] whereas V1054 Ophiuchi Ba-Bb pair is still unresolved).[1][2][note 3]

Outer orbit (V1054 Ophiuchi A - V1054 Ophiuchi Bab):

Period P (yr) 1.717267 ± 0.000039[2]
Period P (days) 627.0 ± 0.2,[1]
627.232 ± 0.014[2]
Semi-major axis a, arcsec 0.2273 ± 0.0004,[1]
0.2256 ± 0.0011[2]
Semi-major axis a, a.u. 1.46683,[1][note 4]
1.45586[2][note 4]
Eccentricity e 0.042 ± 0.001,[1]
0.0433 ± 0.0018[2]
Inclination i, ° 160.3 ± 0.1,[1]
163.1 ± 1.6[2]
Longitude of the
periastron ω, °
306.0 ± 1.5,[1]
115.6 ± 5.1[2]
Position angle of the
ascending node Ω, °
-10.2 ± 0.2,[1]
163.2 ± 3.1[2]
Time of periastron
passage T0
MJD 53943. ± 3.,[1]
1988.143 ± 0.011[2]

The most accurate estimates are marked in bold.

Inner orbit (V1054 Ophiuchi Ba - V1054 Ophiuchi Bb):

Period P (days) 2.965509 ± 0.000006,[1]
2.965522 ± 0.000014[2]
Semi-major axis a, arcsec 0.00687[note 5]
Semi-major axis a, a.u. 0.04432[note 6]
Eccentricity e 0.0209 ± 0.0008,[1]
0.026 ± 0.007[2]
Inclination i, ° 164.18 ± 0.08,[1]
16.3 ± 0.3 or 163.7 ± 0.3[2]
Longitude of the
periastron ω, °
150.0 ± 3.0,[1]
166 ± 16[2]
Position angle of the
ascending node Ω, °
Time of periastron
passage T0
MJD 50919.48 ± 0.03,[1]
HJD 2447337.3 ± 0.14[2]

The most accurate estimates are marked in bold.

Distant components[edit]

Gliese 643[edit]

The projected separation of Gliese 643 from V1054 Ophiuchi A-Bab is 72 arcsec,[1] corresponding at 21.05 light-years to 465 a.u.

V1054 Ophiuchi C (vB 8)[edit]

Main article: Van Biesbroeck 8

The projected separation of V1054 Ophiuchi C (vB 8) from V1054 Ophiuchi A-Bab is about 220 arcsec,[1][2] corresponding at 21.05 light-years to 1420 a.u. Since it is only three times larger than projected separation between Gliese 643 and V1054 Ophiuchi A-Bab, and such a small ratio should render triple system dynamically unstable, it was suggested,[2] that real separation of V1054 Ophiuchi C from V1054 Ophiuchi A-Bab is much larger, at least by factor two,[2] i. e. at least 2840 a.u.

Notes[edit]

  1. ^ a b c From apparent magnitude and parallax.
  2. ^ a b Referred to entire V1054 Ophiuchi Bab subsystem.
  3. ^ At least it was not resolved by 2001.
  4. ^ a b Assuming weighted mean parallax 154.96 mas.
  5. ^ From masses, period and parallax.
  6. ^ From masses and period. According Mazeh et al. 2001, of order of 0.05 a. u.

References[edit]

  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab Ségransan, D.; Delfosse, X.; Forveille, T.; Beuzit, J.-L.; Udry, S.; Perrier, C.; Mayor, M. (2000). "Accurate masses of very low mass stars. III. 16 new or improved masses". Astronomy and Astrophysics 364: 665–673. arXiv:astro-ph/0010585. Bibcode:2000A&A...364..665S. 
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap Mazeh, Tsevi; Latham, David W.; Goldberg, Elad; Torres, Guillermo; Stefanik, Robert P.; Henry, Todd J.; Zucker, Shay; Gnat, Orly; Ofek, Eran O. (2001). "Studies of multiple stellar systems - IV. The triple-lined spectroscopic system V1054 Ophiuchi". Monthly Notices of the Royal Astronomical Society 325: 343–357. arXiv:astro-ph/0102451. Bibcode:2001MNRAS.325..343M. doi:10.1046/j.1365-8711.2001.04419.x. 
  3. ^ RECONS CENSUS OF OBJECTS NEARER THAN 10 PARSECS
  4. ^ a b c Vizier, The Hipparcos and Tycho Catalogues (ESA 1997)
  5. ^ a b c VizieR, Yale Trigonometric Parallaxes, Fourth Edition (van Altena+ 1995)
  6. ^ a b Vizier, Stars within 25 pc of the Sun (Woolley+ 1970)
  7. ^ a b Vizier, Nearby Stars, Preliminary 3rd Version (Gliese+ 1991)
  8. ^ Vizier, Visual binary orbits and masses (Soederhjelm 1999)
  9. ^ a b Vizier, Hipparcos, the New Reduction (van Leeuwen 2007)
  10. ^ Costa, Edgardo; Méndez, René A.; Jao, W.-C.; Henry, Todd J.; Subasavage, John P.; Brown, Misty A.; Ianna, Philip A.; Bartlett, Jennifer (2005). "The Solar Neighborhood. XIV. Parallaxes from the Cerro Tololo Inter-American Observatory Parallax Investigation-First Results from the 1.5 m Telescope Program". The Astronomical Journal 130: 337–349. Bibcode:2005AJ....130..337C. doi:10.1086/430473. 
  11. ^ DENSE Project. 25 pc White Dwarf Sample (see formulae below)
  12. ^ THE ONE HUNDRED NEAREST STAR SYSTEMS brought to you by RECONS (Research Consortium On Nearby Stars)

External links[edit]