G Scorpii

G Scorpii

Location of G Scorpii (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Scorpius
Right ascension	17^h 49^m 51.48081^s[1]
Declination	−37° 02′ 35.8975″[1]
Apparent magnitude (V)	3.21[2]
Characteristics
Evolutionary stage	horizontal branch[3]
Spectral type	K2 III[4]
U−B color index	+1.19[2]
B−V color index	+1.17[2]
Astrometry
Radial velocity (Rv)	+24.7[5] km/s
Proper motion (μ)	RA: 40.59[1] mas/yr Dec.: 27.24[1] mas/yr
Parallax (π)	25.92 ± 0.15 mas[1]
Distance	125.8 ± 0.7 ly (38.6 ± 0.2 pc)
Absolute magnitude (MV)	+0.24[6]
Details[3]
Mass	1.2±0.2 M☉
Radius	20±1 R☉
Luminosity	93±4 L☉
Surface gravity (log g)	2.2 cgs
Temperature	4,535±125 K
Metallicity [Fe/H]	−0.20[7] dex
Rotational velocity (v sin i)	<1.0[8] km/s
Other designations
Fuyue, G Sco, γ Tel, FK5 669, HD 161892, HIP 87261, HR 6630, SAO 209318
Database references
SIMBAD	data

G Scorpii (abbreviated G Sco), also named Fuyue, is a giant star in the constellation of Scorpius. It has an apparent magnitude of +3.19. It is approximately 126 light-years from the Sun.

Nomenclature

G Scorpii below and right (ie. west) of NGC 6441

G Scorpii is the star's Bayer designation. It was formerly situated in the constellation of Telescopium where it was designated γ Telescopii, Latinised to Gamma Telescopii.[9] It was resited in Scorpius and redesignated G Scorpii by Benjamin Apthorp Gould. On 30 June 2017 it was included in the List of IAU-approved Star Names.[10]

G Scorpii bore the traditional name Fuyue (simplified Chinese: 傅说; traditional Chinese: 傅說) in ancient China. Fu Yue was a former slave that became a high-ranking minister to Shang dynasty ruler Wu Ding.

Properties

G Scorpii is an orange K-type giant. The measured angular diameter is 3.94±0.21 mas.[11] At the estimated distance of this system, this yields a physical size of about 16 times the radius of the Sun.[12] Calculations based on its physical properties give a diameter of about 20 R_☉. With an effective surface temperature of 4,535 K, it has a bolometric luminosity of 93 L_☉.[3]

Evolutionary models show that G Scorpii has probably left the red giant branch and is now fusing helium in its core. This makes it a red clump star, at the cool end of the horizontal branch.[3]

Just 5 arcminutes to the east is the globular cluster NGC 6441.[13] At magnitude 3.2, G Scorpii is around 40 times brighter than the entire globular cluster.

References

1. van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
2. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
3. Kallinger, T.; Beck, P. G.; Hekker, S.; Huber, D.; Kuschnig, R.; Rockenbauer, M.; Winter, P. M.; Weiss, W. W.; Handler, G.; Moffat, A. F. J.; Pigulski, A.; Popowicz, A.; Wade, G. A.; Zwintz, K. (2019), "Stellar masses from granulation and oscillations of 23 bright red giants observed by BRITE-Constellation", Astronomy and Astrophysics, 624: A35, arXiv:1902.07531, Bibcode:2019A&A...624A..35K, doi:10.1051/0004-6361/201834514, S2CID 102486794.
4. Gray, R. O.; et al. (July 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, S2CID 119476992.
5. Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
6. Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics, 430: 303–311, arXiv:astro-ph/0409683, Bibcode:2005A&A...430..303C, doi:10.1051/0004-6361:20041440, S2CID 12136256.
7. 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, S2CID 204907220.
8. De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (2014), "A catalog of rotational and radial velocities for evolved stars. V. Southern stars", Astronomy and Astrophysics, 561: A126, arXiv:1312.3474, Bibcode:2014A&A...561A.126D, doi:10.1051/0004-6361/201220762, S2CID 54046583.
9. Ian Ridpath, "Telescopium", Star Tales, retrieved 2020-05-23.
10. Naming Stars, IAU.org, retrieved 16 December 2017.
11. Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039
12. Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3540296921. The radius (R_*) is given by:

    ${\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(38.6\cdot 3.94\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 32.7\cdot R_{\bigodot }\end{aligned}}}$

13. O'Meara, Stephen James (2013), Deep-Sky Companions: Southern Gems, Cambridge University Press, pp. 360–363, Bibcode:2013dcsg.book.....O, ISBN 978-1139851541.