HD 193307 (HR 7766; Gliese 9691) is the primary of a binary star located the southern constellation Telescopium. It has an apparent magnitude of 6.27,[2] placing it near the limit for naked eye visibility, even under ideal conditions. The star is located relatively close at a distance of 102 light years based on Gaia DR3 parallax measurements,[1] but it is receding with a heliocentric radial velocity of 16.9 km/s.[7] At its current distance, HD 193307's brightness is diminished by 0.18 magnitudes due to extinction from interstellar dust[18] and it has an absolute magnitude of +3.80.[8] HD 193307 has a relatively high proper motion, moving at a rate of 437 mas/yr.[19]

HD 193307
Location of HD 193307 (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Telescopium
A
Right ascension 20h 21m 41.03652s[1]
Declination −49° 59′ 57.9001″[1]
Apparent magnitude (V) 6.27[2]
B
Right ascension 20h 21m 39.11678s[3]
Declination −49° 59′ 47.2058″[3]
Apparent magnitude (V) 12.8[4]
Characteristics
A
Spectral type F9 V[5]
U−B color index –0.02[2]
B−V color index +0.55[2]
B
Spectral type M2.5[6]
Astrometry
A
Radial velocity (Rv)16.9±0.65[7] km/s
Proper motion (μ) RA: −357.855 mas/yr[1]
Dec.: −250.604 mas/yr[1]
Parallax (π)32.0547 ± 0.0415 mas[1]
Distance101.7 ± 0.1 ly
(31.20 ± 0.04 pc)
Absolute magnitude (MV)+3.80[8]
B
Radial velocity (Rv)18.33±0.39[9] km/s
Proper motion (μ) RA: −350.120 mas/yr[3]
Dec.: −252.474 mas/yr[3]
Parallax (π)32.0177 ± 0.0193 mas[3]
Distance101.87 ± 0.06 ly
(31.23 ± 0.02 pc)
Details
A
Mass1.15±0.16[10] M
Radius1.49±0.07[11] R
Luminosity2.605±0.006[1] L
Surface gravity (log g)4.11±0.03[12] cgs
Temperature6,059+96
−59
[13] K
Metallicity [Fe/H]−0.34±0.06[14] dex
Rotational velocity (v sin i)<5[15] km/s
Age7.55+0.62
−0.85
[12] Gyr
Other designations
WDS J20217-5000AB[16]
A: 86 G. Telescopii[17], CD–50°12929, CPD−50°11341, FK5 3630, GC 28291, GJ 9691, HD 193307, HIP 100412, HR 7766, SAO 246546[16]
B: WT 703
Database references
SIMBADA
B

There has been disagreements in the stellar classification of the object. Two sources give a class of F9 V,[5] indicating that it is an ordinary F-type main-sequence star. David Stanley Evans gave it a slightly more evolved class of G2 IV-V,[20] meaning that it is a G-type star with a luminosity class intermediate between a subgiant and main sequence star. Nancy Houk's spectral classification catalog lists HD 193307 as G0 V.[21]

The accepted class for HD 193307 is F9 V.[5] The object's current luminosity is 1.49 magnitudes above the ZAMS, indicating that HD 193307 is somewhat evolved.[22] has 1.15 times the Sun's mass and a slightly enlarged radius of 1.49 R.[11] It radiates 2.61 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 6,059 K,[13] which gives it the typical whitish-yellow hue of a late F-type star. At the age of 7.55 billion years,[12] HD 193307 has nearly twice the Sun's age. The star is metal-deficient with an iron abundance 46% that of the Sun ([Fe/H] = −0.34)[14] and it spins slowly with a projected rotational velocity lower than km/s.[15]

WT 703 is a 12th magnitude star located 21.3" away along a position angle of 300°. It has a class of M2.5, indicating that it is a M-type star.[4] WT 703 is located around the same distance as HD 193307 and it has a similar proper motion.

References

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  1. ^ a b c d e f g 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.
  2. ^ a b c d Przybylski, A.; Kennedy, P. M. (1 December 1965). "Radial Velocities and Three-colour Photometry of 166 Southern Stars". Monthly Notices of the Royal Astronomical Society. 131 (1): 95–104. Bibcode:1965MNRAS.131...95P. doi:10.1093/mnras/131.1.95. eISSN 1365-2966. ISSN 0035-8711. S2CID 122694200.
  3. ^ a b c d 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. ^ a b 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. S2CID 119533755.
  5. ^ a b c Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2 June 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. eISSN 1538-3881. ISSN 0004-6256. S2CID 250741593.
  6. ^ Scholz, R.-D. (16 February 2016). "Overlooked wide companions of nearby F stars". Astronomy & Astrophysics. 587: A51. arXiv:1601.01896. Bibcode:2016A&A...587A..51S. doi:10.1051/0004-6361/201527965. eISSN 1432-0746. ISSN 0004-6361. S2CID 118348424.
  7. ^ a b Valenti, Jeff A.; Fischer, Debra A. (July 2005). "Spectroscopic Properties of Cool Stars (SPOCS). I. 1040 F, G, and K Dwarfs from Keck, Lick, and AAT Planet Search Programs". The Astrophysical Journal Supplement Series. 159 (1): 141–166. Bibcode:2005ApJS..159..141V. doi:10.1086/430500. eISSN 1538-4365. ISSN 0067-0049. S2CID 121398064.
  8. ^ a b 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. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
  9. ^ 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. ^ Stassun, Keivan G.; Oelkers, Ryan J.; Pepper, Joshua; et al. (20 August 2018). "The TESS Input Catalog and Candidate Target List". The Astronomical Journal. 156 (3): 102. arXiv:1706.00495. Bibcode:2018AJ....156..102S. doi:10.3847/1538-3881/aad050. eISSN 1538-3881. S2CID 73582386.
  11. ^ a b Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (October 2004). "The angular sizes of dwarf stars and subgiants. Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics. 426 (1): 297–307. arXiv:astro-ph/0404180. Bibcode:2004A&A...426..297K. doi:10.1051/0004-6361:20035930. eISSN 1432-0746. ISSN 0004-6361. S2CID 6077801.
  12. ^ a b c Aguilera-Gómez, Claudia; Ramírez, Iván; Chanamé, Julio (June 2018). "Lithium abundance patterns of late-F stars: an in-depth analysis of the lithium desert". Astronomy & Astrophysics. 614: A55. arXiv:1803.05922. Bibcode:2018A&A...614A..55A. doi:10.1051/0004-6361/201732209. eISSN 1432-0746. ISSN 0004-6361. S2CID 62799777.
  13. ^ a b 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.
  14. ^ a b Ramírez, I.; Fish, J. R.; Lambert, D. L.; Allende Prieto, C. (13 August 2012). "Lithium Abundances in nearby FGK Dwarf and Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, and Exoplanets". The Astrophysical Journal. 756 (1): 46. arXiv:1207.0499. Bibcode:2012ApJ...756...46R. doi:10.1088/0004-637X/756/1/46. eISSN 1538-4357. ISSN 0004-637X. S2CID 119199829.
  15. ^ a b Groot, P. J.; Piters, A. J. M.; Paradijs, van (September 1996). "Rotational velocities of F dwarfs; application of the Fourier-Bessel transformation method" (PDF). Astronomy and Astrophysics Supplement Series. 118 (3): 545–555. Bibcode:1996A&AS..118..545G. doi:10.1051/aas:1996214. ISSN 0365-0138. S2CID 53481766.
  16. ^ a b "HD 193307". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 24, 2021.
  17. ^ 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.
  18. ^ Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society. 472 (4): 3805–3820. arXiv:1709.01160. Bibcode:2017MNRAS.472.3805G. doi:10.1093/mnras/stx2219. eISSN 1365-2966. ISSN 0035-8711. S2CID 118879856.
  19. ^ Knapp, Wilfried; Nanson, John (January 2019). "A Catalog of High Proper Motion Stars in the Southern Sky (HPMS3 Catalog)". Journal of Double Star Observations. 15 (1): 21–41. Bibcode:2019JDSO...15...21K.
  20. ^ Evans, D. S.; Menzies, A.; Stoy, R. H.; Wayman, P. A. (1961). "Fundamental data for southern stars (fourth list)". Royal Greenwich Observatory Bulletins. 48: 389–405. Bibcode:1961RGOB...48..389E.
  21. ^ Houk, Nancy (1978). Michigan catalogue of two-dimensional spectral types for the HD stars: Declinations −53° to −40°. Vol. 2. Bibcode:1978mcts.book.....H.
  22. ^ Nordström, B.; Mayor, M.; Andersen, J.; Holmberg, J.; Pont, F.; Jørgensen, B. R.; Olsen, E. H.; Udry, S.; Mowlavi, N. (16 April 2004). "The Geneva-Copenhagen survey of the Solar neighbourhood". Astronomy & Astrophysics. 418 (3): 989–1019. arXiv:astro-ph/0405198. Bibcode:2004A&A...418..989N. doi:10.1051/0004-6361:20035959. eISSN 1432-0746. ISSN 0004-6361. S2CID 11027621.