HD 123657

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HD 123657
(BY Boötis)
Location of BY Boö (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension 14h 07m 55.755s[1]
Declination +43° 51′ 16.03″[1]
Apparent magnitude (V) 4.98–5.33[2][3]
Characteristics
Evolutionary stage AGB[4]
Spectral type M4.5III[5]
U−B color index 1.66[6]
B−V color index 1.58[6]
R−I color index 1.66[6]
Variable type LB[5]
Astrometry
Radial velocity (Rv)−36.24[7] km/s
Proper motion (μ) RA: +11.443 mas/yr[1]
Dec.: −30.812 mas/yr[1]
Parallax (π)6.0110±0.1554 mas[1]
Distance540 ± 10 ly
(166 ± 4 pc)
Absolute magnitude (MV)−0.90[8]
Details
Mass3.96[9] M☉
Radius131.7+3.4
−3.5[10] R☉
Luminosity1,600±130[11] L☉
Surface gravity (log g)0.66[12] cgs
Temperature3,444±125[11] K
Metallicity [Fe/H]−0.03[13] dex
Other designations
BY Boötis, HD 123657, HIP 69038, HR 5299, GSC 03040-00969, TYC 3040-969-1, BD+44°2325, IRAS 14059+4405, IRC +40253, SAO 44901
Database references
SIMBADdata

HD 123657 (BY Boötis) is a star in the northern constellation of Boötes, near the end of the handle of the Big Dipper. It is a fifth-magnitude star, and can be spotted to the unaided eye in sufficiently dark skies, far from light pollution. Based on stellar parallax measurements, it is about 540 light-years distant.

A light curve for BY Boötis, plotted from Hipparcos data[14]

This is a slow irregular variable with an apparent magnitude varying between 4.98 and 5.33.[2][3] The variability of the brightness of HD 123657 was announced by Joel Stebbins and Charles Morse Huffer in 1928, based on observations made at Washburn Observatory.[15] The star was given its variable star designation, BY Boötis, in 1973.[16]

HD 123657 has a spectral classification of M4.5III,[5] placing it as a cool red giant that exhausted its hydrogen supply. It has expanded to over 132 times the size of the Sun,[10] now radiating 1,600 times its luminosity at a cool photosphere that has an effective temperature of 3,400 K.[11]

References

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  1. ^ 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.
  2. ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  3. ^ a b "VSX : Detail for BY Boo". www.aavso.org. Retrieved 2025-03-11.
  4. ^ Alonso-Hernández, J.; Sánchez Contreras, C.; Sahai, R. (2024). "CO emission survey of asymptotic giant branch stars with ultraviolet excesses". Astronomy and Astrophysics. 684: A77. arXiv:2401.08546. Bibcode:2024A&A...684A..77A. doi:10.1051/0004-6361/202347317.
  5. ^ a b c Alvarez, R.; Jorissen, A.; Plez, B.; Gillet, D.; Fokin, A.; Dedecker, M. (2001). "Envelope tomography of long-period variable stars". Astronomy and Astrophysics. 379: 305–322. arXiv:astro-ph/0109259. Bibcode:2001A&A...379..305A. doi:10.1051/0004-6361:20011261. S2CID 15502307.
  6. ^ a b c Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
  7. ^ Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics. 430: 165. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. S2CID 17804304.
  8. ^ Park, Sunkyung; Kang, Wonseok; Lee, Jeong-Eun; Lee, Sang-Gak (2013). "Wilson-Bappu Effect: Extended to Surface Gravity". The Astronomical Journal. 146 (4): 73. arXiv:1307.0592. Bibcode:2013AJ....146...73P. doi:10.1088/0004-6256/146/4/73. S2CID 119187733.
  9. ^ Charbonnel, C.; Lagarde, N.; Jasniewicz, G.; North, P. L.; Shetrone, M.; Krugler Hollek, J.; Smith, V. V.; Smiljanic, R.; Palacios, A.; Ottoni, G. (2020). "Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era". Astronomy and Astrophysics. 633: A34. arXiv:1910.12732. Bibcode:2020A&A...633A..34C. doi:10.1051/0004-6361/201936360.
  10. ^ a b Baines, Ellyn K.; Clark, James H.; Kingsley, Bradley I.; Schmitt, Henrique R.; Stone, Jordan M. (2025-05-07). "Vintage NPOI: New and Updated Angular Diameters for 145 Stars". The Astronomical Journal. 169 (6): 293. arXiv:2506.02912. doi:10.3847/1538-3881/adc930. ISSN 1538-3881.
  11. ^ a b c McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017-10-01). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770–791. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433. ISSN 0035-8711.
  12. ^ Coelho, Paula R. T.; Bruzual, Gustavo; Charlot, Stéphane (2020). "To use or not to use synthetic stellar spectra in population synthesis models?". Monthly Notices of the Royal Astronomical Society. 491 (2): 2025. arXiv:1910.11902. Bibcode:2020MNRAS.491.2025C. doi:10.1093/mnras/stz3023.
  13. ^ Marrese, P. M.; Boschi, F.; Munari, U. (2003). "High resolution spectroscopy over lambda lambda 8500-8750 Å for GAIA. IV. Extending the cool MK stars sample". Astronomy and Astrophysics. 406 (3): 995. Bibcode:2003A&A...406..995M. doi:10.1051/0004-6361:20030647.
  14. ^ "Hipparcos Tools Interactive Data Access". Hipparcos. ESA. Retrieved 8 December 2021.
  15. ^ Stebbins, Joel; Huffer, C. M. (1928). "The Constancy of the Light of Red Stars". Publications of the Washburn Observatory. 15: 137–174. Bibcode:1928PWasO..15..137S.
  16. ^ 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: 1–22. Bibcode:1973IBVS..834....1K. Retrieved 4 December 2024.