HD 200661

HD 200661
Observation data; Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Equuleus
Right ascension	21h 04m 41.6405s
Declination	02° 56′ 32.1874″
Apparent magnitude (V)	6.41±0.01
Characteristics
Evolutionary stage	horizontal branch
Spectral type	K0 III
U−B color index	0.89
B−V color index	1.06
Astrometry
Radial velocity (Rv)	−12.1 ± 0.2 km/s
Proper motion (μ)	RA: 13.336 mas/yr ; Dec.: 5.800 mas/yr
Parallax (π)	7.5933 ± 0.0353 mas
Distance	430 ± 2 ly ; (131.7 ± 0.6 pc)
Absolute magnitude (MV)	0.53
Details
Mass	1.74 M☉
Radius	10.62 R☉
Luminosity	51.3 L☉
Surface gravity (log g)	2.1 cgs
Temperature	4,740 K
Metallicity [Fe/H]	−0.1 dex
Other designations
	7 G. Equueli, AG 02° 2688, BD 02°4297, GC 29434, HD 200661, HIP 104041, HR 8067, SAO 126519
Database references
SIMBAD	data

HD 200661 (HR 8067) is a solitary star in the equatorial constellation Equuleus. It has an apparent magnitude of 6.41, placing it near the max naked eye visibility. The star is situated at a distance of 430 light years^[1] but is approaching with a heliocentric radial velocity of −12.1 km/s.^[6]

HD 200661 has a stellar classification of K0 III,^[4] indicating that the object is an early K-type giant star that is on the horizontal branch.^[3] It has an angular diameter of 0.75±0.05 mas, which yields a diameter 10.62^[9] times that of the Sun at its estimated distance. At present HD 200661 has 1.74 times the Sun’s mass,^[8] and shines at 51.3 times the luminosity of the Sun^[10] from its enlarged photosphere at an effective temperature of 4,740 K,^[10] giving it a yellow-orange glow.

References

^ ^a ^b ^c ^d ^e ^f 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.
^ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (1 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.
^ ^a ^b Gontcharov, G. A. (November 2008). "Red giant clump in the Tycho-2 catalogue". Astronomy Letters. 34 (11): 785–796. arXiv:1607.00619. Bibcode:2008AstL...34..785G. doi:10.1134/S1063773708110078. ISSN 0004-6299. S2CID 73524157.
^ ^a ^b Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey. 05: 0. Bibcode:1999MSS...C05....0H.
^ ^a ^b Cousins, A. W. J. (1971). "Photometric standard stars". Royal Observatory Annals. 7. Bibcode:1971ROAn....7.....C.
^ ^a ^b 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.
^ Anderson, E.; Francis, Ch. (1 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.
^ ^a ^b ^c Anders, F.; et al. (1 August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy and Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. ISSN 0004-6361. S2CID 131780028.
^ ^a ^b Lang, Kenneth R. (2006). Astrophysical formulae. Astronomy and astrophysics library. Vol. 1 (3 ed.). Birkhäuser. ISBN 3-540-29692-1.. The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(131.7\cdot 0.75\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 21.25\cdot R_{\bigodot }\end{aligned}}$
^ ^a ^b ^c ^d McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433.
^ Lafrasse, Sylvain; Mella, Guillaume; Bonneau, Daniel; Duvert, Gilles; Delfosse, Xavier; Chesneau, Olivier; Chelli, Alain (16 July 2010). "Building the 'JMMC Stellar Diameters Catalog' using SearchCal". Optical and Infrared Interferometry II. Vol. 7734. pp. 77344E. arXiv:1009.0137. Bibcode:2010SPIE.7734E..4EL. doi:10.1117/12.857024. S2CID 32097037.
^ "HR 8067". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 11 September 2021.

[EDR3-1] ^ ^a ^b ^c ^d ^e ^f 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.

[Tycho2000-2] Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (1 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.

[Gontcharov2008-3] Gontcharov, G. A. (November 2008). "Red giant clump in the Tycho-2 catalogue". Astronomy Letters. 34 (11): 785–796. arXiv:1607.00619. Bibcode:2008AstL...34..785G. doi:10.1134/S1063773708110078. ISSN 0004-6299. S2CID 73524157.

[Houk1999-4] Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey. 05: 0. Bibcode:1999MSS...C05....0H.

[Cousin1971-5] Cousins, A. W. J. (1971). "Photometric standard stars". Royal Observatory Annals. 7. Bibcode:1971ROAn....7.....C.

[Famaey2005-6] 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.

[XHIP-7] Anderson, E.; Francis, Ch. (1 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.

[Anders2019-8] Anders, F.; et al. (1 August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy and Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. ISSN 0004-6361. S2CID 131780028.

[Lang2006-9] Lang, Kenneth R. (2006). Astrophysical formulae. Astronomy and astrophysics library. Vol. 1 (3 ed.). Birkhäuser. ISBN 3-540-29692-1.. The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(131.7\cdot 0.75\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 21.25\cdot R_{\bigodot }\end{aligned}}$

[McDonald2017-10] McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433.

[Lafrasse2010-11] Lafrasse, Sylvain; Mella, Guillaume; Bonneau, Daniel; Duvert, Gilles; Delfosse, Xavier; Chesneau, Olivier; Chelli, Alain (16 July 2010). "Building the 'JMMC Stellar Diameters Catalog' using SearchCal". Optical and Infrared Interferometry II. Vol. 7734. pp. 77344E. arXiv:1009.0137. Bibcode:2010SPIE.7734E..4EL. doi:10.1117/12.857024. S2CID 32097037.

[SIMBAD-12] "HR 8067". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 11 September 2021.

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Observation data Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Equuleus
Right ascension	21^h 04^m 41.6405^s^[1]
Declination	02° 56′ 32.1874″^[1]
Apparent magnitude (V)	6.41±0.01^[2]
Characteristics
Evolutionary stage	horizontal branch^[3]
Spectral type	K0 III^[4]
U−B color index	0.89^[5]
B−V color index	1.06^[5]
Astrometry

Radial velocity (R_v)	−12.1 ± 0.2^[6] km/s
Proper motion (μ)	RA: 13.336^[1] mas/yr Dec.: 5.800^[1] mas/yr
Parallax (π)	7.5933 ± 0.0353 mas^[1]
Distance	430 ± 2 ly (131.7 ± 0.6 pc)
Absolute magnitude (M_V)	0.53^[7]

Details

Mass	1.74^[8] `M`_☉
Radius	10.62^[9] `R`_☉
Luminosity	51.3^[10] `L`_☉
Surface gravity (log g)	2.1^[11] cgs
Temperature	4,740^[10] K
Metallicity [Fe/H]	−0.1^[8] dex

Other designations
7 G. Equueli, AG 02° 2688, BD 02°4297, GC 29434, HD 200661, HIP 104041, HR 8067, SAO 126519^[12]
Database references
SIMBAD	data