HD 193721

Last updated
HD 193721
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Octans
Right ascension 20h 33m 17.6366s [1]
Declination −80° 57′ 53.5944″ [1]
Apparent magnitude  (V)5.77±0.01 [2]
Characteristics
Spectral type G6/8 II [3]
U−B color index +0.85 [4]
B−V color index +1.14 [4]
Astrometry
Radial velocity (Rv)8.6±0.7 [5]  km/s
Proper motion (μ)RA: +9.794  mas/yr [1]
Dec.: −16.081  mas/yr [1]
Parallax (π)4.2823 ± 0.165  mas [1]
Distance 760 ± 30  ly
(234 ± 9  pc)
Absolute magnitude  (MV)−0.24 [6]
Details
Mass 3.49 [7]   M☉
Radius 24.38 [8]   R☉
Luminosity 300±5 [9]   L☉
Surface gravity (log g)2.14±0.02 [1]   cgs
Temperature 4953±122 [8]   K
Metallicity [Fe/H]−0.15 [10]   dex
Rotational velocity (v sin i)2.7±1.1 [11]  km/s
Other designations
47 G. Octantis [12] , CPD−81°901, FK5  3994, GC  28453, HD  193721, HIP  101427, HR  7785, SAO  258861, WDS J20333-8058A [13]
Database references
SIMBAD data

HD 193721 (HR 7785) is an astrometric binary [14] in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.77, [2] allowing it to be faintly seen with the naked eye. Parallax measurements place the system 760 light years [1] away from the Solar System and it is currently receding with a heliocentric radial velocity 8.6  km/s . [5]

HD 193721 has a stellar classification of G6/8 II [3] — intermediate between a G6 and 8 bright giant. At present it has 3.49 times the mass of the Sun, [7] but has expanded to 24.4 times its girth. [8] It shines with a luminosity of 300  L☉ [9] from its enlarged photosphere at an effective temperature of 4,953  K , [8] giving a yellow hue. HD 193721 is metal deficient with an iron abundance 71% that of the Sun [10] and spins leisurely with a projected rotational velocity of 2.7  km/s . [11]

The system has an companion designated CPD −81°900. The object has a spectral classification of F8 [15] and is located 25.5″ along a position angle of 0° (as of 1998). [16] CPD −81°900 is a foreground object, having a higher parallax [17] and different proper motion. [16]

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<span class="mw-page-title-main">1 Camelopardalis</span> Double star system in the constellation Camelopardalis

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−2.2 km/s and thus is a probable runaway star.

HD 85951, formally named Felis, is a solitary orange hued star in the constellation Hydra. It has an apparent magnitude of 4.94, making it faintly visible to the naked eye under ideal conditions. Based on parallax measurements, the object is about 570 light-years away from the Sun and is receding with a heliocentric radial velocity of 50 km/s.

HD 122862 is a solitary star in the southern circumpolar constellation Apus. It has an apparent magnitude of 6.02, allowing it to be faintly seen with the naked eye under ideal conditions. The star is relatively close at a distance of 95 light years, but is approaching the Sun with a radial velocity of −21.11 km/s.

<span class="mw-page-title-main">1 Delphini</span> Star in the constellation Delphinus

1 Delphini is the Flamsteed designation for a close binary star in the equatorial constellation Delphinus. With a combined apparent magnitude of 6.08, it is barely visible to the naked eye, even under ideal conditions. Parallax measurements put the components at a distance 703 and 780 light years respectively. However, its approaching the Solar System with a radial velocity of 15 km/s.

HD 50002 is a solitary star in the southern circumpolar constellation Volans. It is faintly visible to the naked eye with an apparent magnitude of 6.09 and is located at a distance of 708 light years. However, it is drifting further with a heliocentric radial velocity of 5.1 km/s.

HD 53501, is a solitary star in the southern circumpolar constellation Volans. It has an apparent magnitude of 5.18, allowing it to be seen with the naked eye under ideal conditions. The object is located at a distance of 308 light years but is receding with a heliocentric radial velocity of 39 km/s.

HR 3831, also known as HD 83368, is a binary star system in the southern constellation of Vela at a distance of 233 light years. This object is barely visible to the naked eye as a dim, blue star with an apparent visual magnitude of 6.232. It is approaching the Earth with a heliocentric radial velocity of 4.0±0.3 km/s.

Pi<sup>2</sup> Octantis Star in the constellation Octans

Pi2 Octantis, Latinized from π2 Octantis, is a solitary star situated in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.64, allowing it to be faintly visible to the naked eye under ideal conditions. Located 1,570 light years away, the star is approaching the Sun with a heliocentric radial velocity of −13.8 km/s.

HD 64307, also known as HR 3075, is a solitary, orange hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.35, allowing it to be faintly seen with the naked eye. Based on parallax measurements from the Gaia spacecraft, The object is estimated to be 690 light years distant. It appears to be receding from the Sun, having a heliocentric radial velocity of 34 km/s.

13 Delphini is a binary star in the equatorial constellation Delphinus, with a combined apparent magnitude of 5.64. The system is located at a distance of 471 light years but is approaching the Solar System with a heliocentric radial velocity of about −7 km/s.

<span class="mw-page-title-main">HD 199223</span> Double star in the constellation Delphinus.

HD 199223 is a double star in the equatorial constellation Delphinus. However, the system was originally in Equuleus prior to the creation of official IAU constellation borders. The components have a separation of 2″ at a position angle of 282° as of 2016. They have apparent magnitudes of 6.34 and 7.49 and distances of 354 and 359 light years respectively. The system is drifting closer with a radial velocity of −33 km/s.

HD 120213 is a solitary star in the southern circumpolar constellation Chamaeleon. It is faintly visible to the naked eye with an apparent magnitude of 5.94 and is estimated to be 910 light years away from the Solar System. However, the object is drifting closer with a heliocentric radial velocity of −35 km/s.

HD 193373 is a solitary red hued star located in the equatorial constellation Delphinus. It has an apparent magnitude of 6.21, placing it near the limit for naked eye visibility. Parallax measurements place it 846 light years distant and it is currently receding with a heliocentric radial velocity of 22.7 km/s.

HD 194612 is a solitary orange hued star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.9, making it visible to the naked eye under ideal conditions. Parallax measurements place it at a distance of 760 light years and it has a low heliocentric radial velocity of 0.3 km/s.

HD 182509, also designated as HR 7370, is an orange hued star located in the southern constellation Telescopium. It has an apparent magnitude of 5.69, making it faintly visible to the naked eye if viewed under ideal conditions. Parallax measurements place the object at a distance of 635 light years. It has a poorly constrained heliocentric radial velocity of −5 km/s, indicating that it is drifting towards the Solar System.

References

  1. 1 2 3 4 5 6 7 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. 1 2 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN   0004-6361.
  3. 1 2 Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations -90_ to -53_ƒ0. Bibcode:1975mcts.book.....H.
  4. 1 2 Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
  5. 1 2 Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv: 1606.08053 . Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. ISSN   1063-7737. S2CID   119231169.
  6. ↑ Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. ISSN   1063-7737. S2CID   119257644.
  7. 1 2 Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv: 2109.10912 . Bibcode:2022A&A...657A...7K. doi: 10.1051/0004-6361/202142146 . eISSN   1432-0746. ISSN   0004-6361.
  8. 1 2 3 4 Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv: 1905.10694 . Bibcode:2019AJ....158..138S. doi: 10.3847/1538-3881/ab3467 . ISSN   0004-6256.
  9. 1 2 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR.
  10. 1 2 Anders, F.; et al. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics. 628: A94. arXiv: 1904.11302 . Bibcode:2019A&A...628A..94A. doi: 10.1051/0004-6361/201935765 . ISSN   0004-6361.
  11. 1 2 De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (January 2014). "A catalog of rotational and radial velocities for evolved stars: V. Southern stars⋆⋆⋆". Astronomy & Astrophysics. 561: A126. arXiv: 1312.3474 . Bibcode:2014A&A...561A.126D. doi: 10.1051/0004-6361/201220762 . ISSN   0004-6361.
  12. ↑ Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
  13. ↑ "HR 7785". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved July 1, 2022.
  14. ↑ Frankowski, A.; Jancart, S.; Jorissen, A. (19 December 2006). "Proper-motion binaries in the Hipparcos catalogue". Astronomy & Astrophysics. 464 (1): 377–392. arXiv: astro-ph/0612449 . Bibcode:2007A&A...464..377F. doi: 10.1051/0004-6361:20065526 . eISSN   1432-0746. ISSN   0004-6361.
  15. ↑ Stoy, R. H. (1968). "Cape photographic catalague for 1950.0, zones −80° to −90°". Annals of the Cape Observatory. 22. Bibcode:1968AnCap..22.....S.
  16. 1 2 Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi: 10.1086/323920 . ISSN   0004-6256.
  17. ↑ 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.
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