HD 202908

Last updated
HD 202908
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Equuleus
A
Right ascension 21h 18m 34.85s [1]
Declination +11° 34′ 08.2″ [1]
Apparent magnitude  (V)7.25±0.03 [2]
B
Right ascension 21h 18m 34.80s [1]
Declination +11° 34′ 08.0″ [1]
Apparent magnitude  (V)8.87±0.14 [2]
Characteristics
Spectral type G0 V (combined) [3]
U−B color index +0.07 [4]
B−V color index +0.56 [4]
Aa
Spectral type F9 V [5] or G1 V [6]
Ab
Spectral type G0 V [5] or G2 V [6]
B
Spectral type G1.5 V [5] or G6 V [7]
Astrometry
Radial velocity (Rv)6.24±0.04 [8]  km/s
Proper motion (μ)RA: +29.213  mas/yr [9]
Dec.: −49.564  mas/yr [9]
Parallax (π)19.3447 ± 0.0543  mas [9]
Distance 168.6 ± 0.5  ly
(51.7 ± 0.1  pc)
A
Absolute magnitude  (MV)+3.73±0.13 [2]
B
Absolute magnitude  (MV)+5.35±0.19 [2]
Orbit [10]
PrimaryA
CompanionB
Period (P)28,685±173  d
Semi-major axis (a)0.5177±0.0046″
Eccentricity (e)0.8651±0.0008
Inclination (i)100.36±0.16°
Longitude of the node (Ω)255.03±0.17°
Periastron epoch (T)24,468,123±3  JD
Argument of periastron (ω)
(secondary)		171.9±0.3°
Semi-amplitude (K1)
(primary)		6.13±0.07 km/s
Semi-amplitude (K2)
(secondary)		13.95±0.09 km/s
Orbit [10]
PrimaryAa
CompanionAb
Period (P)3.9660465±0.0000015  d
Eccentricity (e)0.0033±0.0008
Argument of periastron (ω)
(secondary)		271±13°
Semi-amplitude (K1)
(primary)		66.03±0.06 km/s
Semi-amplitude (K2)
(secondary)		69.69±0.06 km/s
Details
The System
Metallicity [Fe/H]−0.04 [11]   dex
Age 6.4±0.7 [12]   Gyr
The A Subystem
Temperature 6,100±150 [13]   K
Rotational velocity (v sin i)10 [14]  km/s
Aa
Mass 1.14 [15]   M☉
Radius 1.06±0.08 [13]   R☉
Luminosity 1.41+0.15
−0.14 [13]   L☉
Ab
Mass 1.08 [15]   M☉
Radius 0.97±0.08 [13]   R☉
Luminosity1.16+0.13
−0.11 [13]   L☉
B
Mass 0.97 [15]   M☉
Radius 0.91±0.08 [13]   R☉
Luminosity 0.84+0.09
−0.08 [13]   L☉
Temperature 5,703±1,090 [2]   K
Rotational velocity (v sin i)9 [14]  km/s
Other designations
AG+11°2644, BD+10°4514, GC  29812, HD  202908, HIP  105200, SAO  107015, ADS  14839AB, CCDM J21186+1134AB, WDS J21186+1134AB [16]
Database references
SIMBAD The system
A
B

HD 202908, also known as HIP 105200, is a triple star located in the equatorial constellation Equuleus. It has an apparent magnitude of 7.01, [17] making it readily visible in binoculars but not to the naked eye. When resolved, the components have apparent magnitudes of 7.25 and 8.87 respectively. [2] The system is located relatively close at a distance of 169 light years based on Gaia DR3 parallax measurements [9] but it is receding with a heliocentric radial velocity of 6.24  km/s . [8]

Contents

Stellar system

Aa
Period = 3.966 d
Ab
Separation = 0.5″
Period = 78 y
B

Hierarchy of orbits in the HD 202908 system [5]

The system was first observed by astronomer S.W. Burnham. [18]

The "A" component is a double-lined spectroscopic binary that contains two solar-type stars with spectral classifications of F9 V and G0 V respectively. [5] The pair take roughly 4 days to orbit each other. [10]

The tertiary companion designated "B" has a class of G1.5 V, indicating that it is an ordinary G-type main-sequence star like our Sun. HD 202908 A and B both complete an eccentric orbit every 78 years. [10]

Physical characteristics

HD 202908 Aa and Ab have masses 1.08 and 1.14 times that of the Sun [15] and radii 97% and 106% of the Sun respectively. [13] The former radiates 1.41 times the luminosity of the Sun from its photosphere and the latter radiates 1.16 times the Sun's luminosity. [13] The A subsystem has an effective temperature of 6,100  K , [13] giving it a whitish-yellow hue.

The B component has 97% the mass of the Sun [15] and 91% of its radius. It radiates 84% of the Sun's luminosity [13] from its photosphere at an effective temperature of 5,703 K. [2] The system is estimated to be 6.4 billion years old. [12]

Related Research Articles

Tau1 Capricorni is a star in the constellation Capricornus. It has an apparent magnitude of 6.76, making it readily visible in binoculars, but not to the naked eye. Located approximately 750 light years from Earth, the star is receding with a heliocentric radial velocity of 18.5 km/s. Due to its location near the ecliptic, τ1 Cap can be occulted by the Moon and rarely planets.

HR 6806 or HD 166620 is a solitary, orange, main sequence, and Sun-like star located thirty-six light-years away, in the constellation Hercules. The star is smaller than the Sun, with around 79% of the solar mass and radius, and 35% of the solar luminosity. It appears to be rotating slowly with an estimated period of 42 days. In 1988, it was noticed that the star had an inactive chromosphere, with a surface magnetic field strength of only 1,500 G. From 1990 activity in the chromosphere increased, inline with a 16 year stellar cycle previously observed. But, sometime after 1994 chromospheric activity greatly reduced, and has stayed flat for more than 16 years. As of 2022, the star appears to have entered the equivalent of a Maunder minimum. The star is around six billion years of age.

HD 87822 is a triple star in the northern constellation of Leo Minor. The inner pair orbit each other with a period of about 18 years.

HD 92589 is a double star in the constellation Antlia. The system has a combined apparent magnitude of 6.39, placing it near the limit of naked eye visibility. The system is located about 590 light years away based on its parallax shift and has a heliocentric radial velocity of 11 km/s. This indicates that it is drifting away from the Solar System.

HD 165259, also known as HR 6751 is a triple star system located in the southern circumpolar constellation of Apus. It has an apparent magnitude of 5.86, making it faintly visible to the naked eye Parallax measurements place the system at a distance of 138 light years, and it is currently receding with a heliocentric radial velocity of 13.1 km/s.

HD 30442 is a solitary star in the northern circumpolar constellation Camelopardalis. It is faintly visible to the naked eye with an apparent magnitude of 5.47 and is estimated to be 403 light years away from the Solar System. The object has a heliocentric radial velocity of −37 km/s, indicating that it is drifting closer.

HD 115337 is a binary star located in the northern circumpolar constellation Camelopardalis. The pair have a combined apparent magnitude of 6.25, placing it near the limit for naked eye visibility. Parallax measurements place the system at a distance of 698 light years. It has a heliocentric radial velocity of −9.4 km/s, indicating that it is drifting towards the Solar System.

<span class="mw-page-title-main">HD 203842</span> Star in the constellation Equuleus

HD 203842, also known as HR 8191 or rarely 30 G. Equueli, is a solitary, yellowish-white hued star located in the constellation Equuleus. It has an apparent magnitude of 6.32, placing it near the limit for naked eye visibility, even under ideal conditions. Gaia DR3 parallax measurements imply a distance of 374 light years, and it is currently drifting closer with a somewhat constrained heliocentric radial velocity of −21.8 km/s. At its current distance HD 203842's brightness is diminished by 0.15 magnitudes due to interstellar dust and it has an absolute magnitude of +1.06.

<span class="mw-page-title-main">Iota Delphini</span> A-type giant star in the constellation Delphinus

Iota Delphini is a star in the constellation Delphinus. It has an apparent magnitude of about 5.4, meaning that it is just barely visible to the naked eye. Based upon parallax measurements made by the Gaia spacecraft, this star is located at a distance of 196 light years.

HD 97413 is a binary star located in the southern constellation Centaurus. The system has a combined magnitude of 6.27, placing it near the limit for naked eye visibility. Based on parallax measurements from the Gaia spacecraft, the system is located 320 light years away from the Solar System.

HD 126053 is the Henry Draper Catalogue designation for a star in the equatorial constellation of Virgo. It has an apparent magnitude of 6.25, which means it is faintly visible to the naked eye. According to the Bortle scale, it requires dark suburban or rural skies to view. Parallax measurements made by the Hipparcos spacecraft provide an estimated distance of 57 light years to this star. It is drifting closer with a heliocentric radial velocity of −19.2 km/s.

HR 4098, also known as HD 90508, is a binary star system in the northern constellation of Ursa Major at a distance of 75 light years. This object is barely visible to the naked eye as a dim, yellow star with an apparent visual magnitude of 6.45. It is approaching the Earth with a heliocentric radial velocity of 7.2±0.2 km/s.

<span class="mw-page-title-main">HD 27022</span> Star in the constellation Camelopardalis

HD 27022, also known as HR 1327, is a star located in the northern circumpolar constellation Camelopardalis. The object has also been designated as 20 H. Camelopardalis, but is not commonly used in modern times. It has an apparent magnitude of 5.27, allowing it to be faintly visible to the naked eye. Based on parallax measurements from Gaia DR3, the star has been estimated to be 347 light years away. It appears to be approaching the Solar System, having a heliocentric radial velocity of −19.5 km/s.

HD 46588 is a star in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.44, allowing it to be faintly seen with the naked eye. The object is relatively close at a distance of only 59 light years but is receding with a heliocentric radial velocity of 15 km/s.

HD 72945 and HD 72946 form a co-moving star system in the northern constellation of Cancer. HD 72945 is a binary star that is dimly visible to the naked eye as a point of light with an apparent visual magnitude of 5.91. At an angular separation of 10.10″ is the fainter companion star HD 72946 at magnitude 7.25. It is being orbited by a brown dwarf. The system as a whole is located at a distance of approximately 84 light years from the Sun based on parallax measurements.

HD 46815 is a solitary star in the southern constellation Columba. It is faintly visible to the naked eye with an apparent magnitude of 5.4 and is estimated to be 408 light years away. However, it is receding with a heliocentric radial velocity of 32.2 km/s.

<span class="mw-page-title-main">HD 201772</span> Star in the constellation Microscopium

HD 201772, also known as HR 8104, is a yellowish-white hued star located in the southern constellation Microscopium. It has an apparent magnitude of 5.26, making it one of the brighter members of this generally faint constellation. The object is located relatively close at a distance of 111 light-years based on Gaia DR3 parallax measurements but is approaching closer with a heliocentric radial velocity of −41 km/s. At its current distance, HD 201772's brightness is diminished by 0.11 magnitudes due to interstellar dust.

<span class="mw-page-title-main">HD 117566</span> High proper motion star; Camelopardalis

HD 117566, also known as HR 5091, is a solitary yellow-hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.74, making it faintly visible to the naked eye. This object is relatively close at a distance of 291 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of 14 km/s. At its current distance, HD 117566's brightness is diminished by 0.12 magnitudes due to interstellar dust.

<span class="mw-page-title-main">HD 204018</span> Visual binary in Microscopium

HD 204018, also designated as HR 8202, is a visual binary located in the southern constellation Microscopium. The primary has an apparent magnitude of 5.58, making it faintly visible to the naked eye under ideal conditions. The companion has an apparent magnitude of 8.09. The system is located relatively close at a distance of 176 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of 18.3 km/s. At its current distance, HD 204018's combined brightness is diminished by 0.13 magnitudes due to interstellar dust.

<span class="mw-page-title-main">HD 27322</span> A-type dwarf; Camelopardalis

HD 27322, also known as HR 1342, is a binary star located in the northern circumpolar constellation Camelopardalis. The visible component is faintly visible to the naked eye as a white-hued point of light with an apparent magnitude of 5.92. The object is located relatively close at a distance of 313 light-years based on Gaia DR3 parallax measurements, and it is drifting closer with a heliocentric radial velocity of approximately −13 km/s. At its current distance, HD 27322's brightness is diminished by 0.24 magnitudes due to interstellar extinction and it has an absolute magnitude of +0.98.

References

  1. 1 2 3 4 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.
  2. 1 2 3 4 5 6 7 ten Brummelaar, Theo; Mason, Brian D.; McAlister, Harold A.; Roberts, Jr., Lewis C.; Turner, Nils H.; Hartkopf, William I.; Bagnuolo, Jr., William G. (May 2000). "Binary Star Differential Photometry Using the Adaptive Optics System at Mount Wilson Observatory". The Astronomical Journal. 119 (5): 2403–2414. Bibcode:2000AJ....119.2403T. doi: 10.1086/301338 . ISSN   0004-6256.
  3. ↑ Abt, H. A. (March 1981). "Visual multiples. VII - MK classifications". The Astrophysical Journal Supplement Series. 45: 437. Bibcode:1981ApJS...45..437A. doi: 10.1086/190719 . eISSN   1538-4365. ISSN   0067-0049. S2CID   121286745.
  4. 1 2 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M
  5. 1 2 3 4 5 Fekel, F. C. Jr. (September 1981). "HD 202908 - A young, solar-type triple system". The Astrophysical Journal. 248: 670. Bibcode:1981ApJ...248..670F. doi: 10.1086/159191 . eISSN   1538-4357. ISSN   0004-637X.
  6. 1 2 Docobo, Jose A.; Andrade, Manuel (20 November 2006). "A Methodology for the Description of Multiple Stellar Systems with Spectroscopic Subcomponents". The Astrophysical Journal. 652 (1): 681–695. Bibcode:2006ApJ...652..681D. doi: 10.1086/508053 . eISSN   1538-4357. ISSN   0004-637X.
  7. ↑ Christy, James W.; Walker, R. L. Jr. (October 1969). "MK Classification of 142 Visual Binaries". Publications of the Astronomical Society of the Pacific. 81: 643. Bibcode:1969PASP...81..643C. doi: 10.1086/128831 . eISSN   1538-3873. ISSN   0004-6280. S2CID   122411453.
  8. 1 2 Karataş, Y.; Bilir, S.; Eker, Z.; Demircan, O. (April 2004). "Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution". Monthly Notices of the Royal Astronomical Society. 349 (3): 1069–1092. arXiv: astro-ph/0404219 . Bibcode:2004MNRAS.349.1069K. doi: 10.1111/j.1365-2966.2004.07588.x . eISSN   1365-2966. ISSN   0035-8711.
  9. 1 2 3 4 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.
  10. 1 2 3 4 Fekel, Francis C.; Scarfe, C. D.; Barlow, D. J.; Duquennoy, Antoine; McAlister, Harold A. (March 1997). "New and Improved Parameters of HD 202908=ADS 14839: A Spectroscopic-Visual Triple System". The Astronomical Journal. 113: 1095. Bibcode:1997AJ....113.1095F. doi: 10.1086/118327 . ISSN   0004-6256.
  11. ↑ Casagrande, L.; Schönrich, R.; Asplund, M.; Cassisi, S.; Ramírez, I.; Meléndez, J.; Bensby, T.; Feltzing, S. (26 May 2011). "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s): Improved astrophysical parameters for the Geneva-Copenhagen Survey⋆". Astronomy & Astrophysics. 530: A138. arXiv: 1103.4651 . Bibcode:2011A&A...530A.138C. doi: 10.1051/0004-6361/201016276 . eISSN   1432-0746. ISSN   0004-6361. S2CID   56118016.
  12. 1 2 Holmberg, J.; Nordström, B.; Andersen, J. (July 2009). "The Geneva-Copenhagen survey of the solar neighbourhood: III. Improved distances, ages, and kinematics". Astronomy & Astrophysics. 501 (3): 941–947. arXiv: 0811.3982 . Bibcode:2009A&A...501..941H. doi: 10.1051/0004-6361/200811191 . ISSN   0004-6361.
  13. 1 2 3 4 5 6 7 8 9 10 11 Torres, G.; Andersen, J.; Giménez, A. (7 October 2009). "Accurate masses and radii of normal stars: modern results and applications". The Astronomy and Astrophysics Review. 18 (1–2): 67–126. arXiv: 0908.2624 . Bibcode:2010A&ARv..18...67T. doi:10.1007/s00159-009-0025-1. eISSN   1432-0754. ISSN   0935-4956.
  14. 1 2 Cutispoto, G.; Pastori, L.; Pasquini, L.; de Medeiros, J. R.; Tagliaferri, G.; Andersen, J. (March 2002). "Fast-rotating nearby solar-type stars". Astronomy & Astrophysics. 384 (2): 491–503. Bibcode:2002A&A...384..491C. doi: 10.1051/0004-6361:20020040 . eISSN   1432-0746. ISSN   0004-6361. S2CID   56201169.
  15. 1 2 3 4 5 Tokovinin, Andrei (14 March 2014). "From Binaries to Multiples. I. Data on F and G Dwarfs within 67 pc of the Sun". The Astronomical Journal. 147 (4): 86. arXiv: 1401.6825 . Bibcode:2014AJ....147...86T. doi: 10.1088/0004-6256/147/4/86 . eISSN   1538-3881. ISSN   0004-6256. S2CID   53965918.
  16. ↑ "HD 202908". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved March 21, 2023.
  17. ↑ 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. S2CID   17128864.
  18. ↑ Burnham, S. W. (12 December 1873). "A Third Catalogue of 76 New Double Stars, discovered with a 6-inch Alvan Clark Refractor". Monthly Notices of the Royal Astronomical Society. 34 (2): 59–71. Bibcode:1873MNRAS..34...59B. doi: 10.1093/mnras/34.2.59 . eISSN   1365-2966. ISSN   0035-8711.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.