HD 221420

Last updated
HD 221420
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Octans
Right ascension 23h 33m 19.5789s [1]
Declination −77° 23′ 07.194″ [1]
Apparent magnitude  (V)5.81±0.01 [2]
Characteristics
Spectral type G2 IV-V [3]
U−B color index +0.31 [4]
B−V color index +0.68 [4]
Astrometry
Radial velocity (Rv)26.48±0.02 [5]  km/s
Proper motion (μ)RA: +16.306  mas/yr [1]
Dec.: +0.736  mas/yr [1]
Parallax (π)32.1023 ± 0.0325  mas [1]
Distance 101.6 ± 0.1  ly
(31.15 ± 0.03  pc)
Absolute magnitude  (MV)+3.33 [6]
Details
Mass 1.35±0.01 [7]   M☉
Radius 1.95±0.01 [7]   R☉
Luminosity 4.01±1 [8]   L☉
Surface gravity (log g)4.03±0.03 [7]   cgs
Temperature 5,830±44 [9]   K
Metallicity [Fe/H]+0.34±0.07 [10]   dex
Rotational velocity (v sin i)2.8±0.5 [11]  km/s
Age 3.65±0.23 [7]   Gyr
Other designations
83 G. Octantis, CPD−78°1473, FK5  3887, GC  32742, GJ  4340, HD  221420, HIP  116250, HR  8935, SAO  258154 [12] [13]
Database references
SIMBAD data
Exoplanet Archive data
Extrasolar Planets
Encyclopaedia 		data

HD 221420 (HR 8935; Gliese 4340) is a likely binary star system [7] in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.81, allowing it to be faintly seen with the naked eye. The object is relatively close at a distance of 102 light years but is receding with a heliocentric radial velocity of 26.5  km/s .

HD 221420 has a stellar classification of G2 IV-V, [3] indicating a solar analogue with a luminosity class intermediate between a subgiant and a main sequence star. The object is also extremely chromospherically inactive. [3] It has a comparable mass to the Sun and a diameter of 1.95  R☉ . [7] It shines with a luminosity of 4  L☉ [8] from its photosphere at an effective temperature of 5,830  K , [9] giving a yellow glow. HD 221420 is younger than the Sun at 3.65 billion years. [7] Despite this, the star is already beginning to evolve off the main sequence. Like most planetary hosts, HD 221420 has a metallicity over twice of that of the Sun [7] and spins modestly with a projected rotational velocity 2.8  km/s . [11]

There is a mid-M-dwarf star with a similar proper motion and parallax to HD 221420, which is likely gravitationally bound to it. The two stars are separated by 698 arcseconds, corresponding to a distance of 21,756  AU . [7]

Planetary system

In a 2019 doppler spectroscopy survey, an exoplanet was discovered orbiting the star. The planet was originally thought to be a super Jupiter, having a minimum mass of 9.7  MJ . [9] However, later observations using Hipparcos and Gaia astrometry found it to be a brown dwarf with a high-inclination orbit, [7] [10] [14] revealing a true mass of 23  MJ . [7]

The HD 221420 A planetary system [7]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(years)		 Eccentricity Inclination Radius
b22.9±2.2  MJ 10.15+0.59
−0.38		27.62+2.45
−1.54		0.14+0.04
−0.03		164.0+1.9
−2.6 ° 		—

Related Research Articles

HD 101930, also known as Gliese 3683, is an orange hued star located in the southern constellation Centaurus. It has an apparent magnitude of 8.21, making it faintly visible in binoculars but not to the naked eye. The system is located relatively close at a distance of 98 light years but is receding with a heliocentric radial velocity of 18.4 km/s. A 2007 multicity survey found a co-moving companion located 73″ away, making it a binary star. It has a class of M0-1 and a mass of 0.7 M☉.

HD 81040 is a star in the equatorial constellation of Leo. With an apparent visual magnitude of +7.73 it is too dim to be visible to the naked eye but can be viewed with a small telescope. The star is located at a distance of 112 light years from the Sun based on parallax. It is drifting further away with a radial velocity of +49 km/s, having come to within 48 light-years some 527,000 years ago.

HD 82205 is a solitary star in the southern constellation Antlia. It is faintly visible to the naked eye with an apparent magnitude of 5.48 and is estimated to be 810 light years distant based on parallax measurements. However, it is receding with a heliocentric radial velocity of 12 km/s.

HD 161988, also known as HR 6635, is a solitary, orange hued star located in the southern circumpolar constellation Apus. It has an apparent magnitude of 6.07, allowing it to be faintly visible to the naked eye. Parallax measurements place it at a distance of 621 light years, and it is currently receding with a heliocentric radial velocity of 36.8 km/s.

<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.

HD 64484 is a solitary star in the southern circumpolar constellation Volans. With an apparent magnitude of 5.76, it is faintly visible to the naked eye under dark skies. Parallax measurements place it at a distance of 458 light years but is receding with a heliocentric radial velocity of 11 km/s.

HD 50002 is a solitary star in the southern circumpolar constellation Volans. It is faintly visible to the naked eye with an apparent magnitude of 6.09 and is located at a distance of 708 light years. However, it is drifting further with a heliocentric radial velocity of 5.1 km/s.

HD 63584 is a solitary star in the southern circumpolar constellation Volans. With an apparent magnitude of 6.15, it is barely visible to the naked eye under ideal conditions. The star is located 420 light years away based on parallax, but is drifting away with a radial velocity of 10.4 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.

HD 39194 is a star located in the southern circumpolar constellation Mensa. It has an apparent magnitude of 8.07, making it readily visible in binoculars but not to the naked eye. The object is relatively close at a distance of 86 light years but is receding with a heliocentric radial velocity of 13.9 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 194012 is a star in the equatorial constellation Delphinus. It has an apparent magnitude of 6.15, making it visible to the naked eye under ideal conditions. The star is relatively close at a distance of only 85 light years but is receding with a heliocentric radial velocity of 4.5 km/s.

HD 193556 is a solitary star in the equatorial constellation Delphinus. It has an apparent magnitude of 6.17, making it visible to the naked eye under ideal conditions. Parallax measurements place the object at a distance of 467 light years and it is currently receding with a heliocentric radial velocity of 11.7 km/s.

HD 193373 is a solitary red hued star located in the equatorial constellation Delphinus. It has an apparent magnitude of 6.21, placing it near the limit for naked eye visibility. Parallax measurements place it 846 light years distant and it is currently receding with a heliocentric radial velocity of 22.7 km/s.

HD 182509, also designated as HR 7370, is an orange hued star located in the southern constellation Telescopium. It has an apparent magnitude of 5.69, making it faintly visible to the naked eye if viewed under ideal conditions. Parallax measurements place the object at a distance of 635 light years. It has a poorly constrained heliocentric radial velocity of −5 km/s, indicating that it is drifting towards the Solar System.

HD 183552, also known as HR 7411, is a probable spectroscopic binary located in the southern constellation Telescopium. The system has a combined apparent magnitude of 5.74, allowing it to be faintly visible to the naked eye. Based on parallax measurements from the Gaia spacecraft, it is estimated to be 337 light years distant. The value is horribly constrained, but it appears to receding with a radial velocity of 14 km/s.

HD 58425, also known as HR 2830, is an astrometric binary located in the northern circumpolar constellation Camelopardalis. It is faintly visible to the naked eye as an orang point of light at an apparent magnitude of 5.64. Based on parallax measurements from Gaia DR3, the system is estimated to be 470 light years away from Earth. It appears to be rapidly receding from the Sun, having a heliocentric radial velocity of 58.6 km/s. HD 58425 is listed as 54 Ursae Majoris in Johann Hevelius' catalogue, but this was dropped after the official IAU's official constellation borders were drawn.

<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 22764</span> Double star; Camelopardalis

HD 22764, also known as HR 1112, is an orange hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.78, allowing it to be faintly visible to the naked eye. The object is located relatively far at a distance of approximately 1,770 light years based on Gaia DR3 parallax measurements but is approaching the Solar System with a heliocentric radial velocity of −12.5 km/s. At its current distance, HD 22764's brightness is diminished by 0.66 magnitudes due to interstellar dust.

HD 200779 is a solitary star located in the equatorial constellation Equuleus, the foal. It has an apparent magnitude of 8.27, making it readily visible in binoculars but not to the naked eye. The object is located relatively close at a distance of 49 light years based on Gaia DR3 parallax measurements, and it is approaching rapidly with a heliocentric radial velocity of −67 km/s. It is classified as a high proper motion star, with a total proper motion of 569 mas/yr.

References

  1. 1 2 3 4 5 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. ↑ 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.
  3. 1 2 3 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.
  4. 1 2 Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
  5. ↑ Jofré, E.; Petrucci, R.; Saffe, C.; Saker, L.; Artur de la Villarmois, E.; Chavero, C.; Gómez, M.; Mauas, P. J. D. (26 January 2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. arXiv: 1410.6422 . Bibcode:2015A&A...574A..50J. doi: 10.1051/0004-6361/201424474 . eISSN   1432-0746. ISSN   0004-6361.
  6. ↑ 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. ISSN   1063-7737. S2CID   119257644.
  7. 1 2 3 4 5 6 7 8 9 10 11 12 Venner, Alexander; Vanderburg, Andrew; Pearce, Logan A. (11 June 2021). "True Masses of the Long-period Companions to HD 92987 and HD 221420 from Hipparcos–Gaia Astrometry". The Astronomical Journal. 162 (1): 12. arXiv: 2104.13941 . Bibcode:2021AJ....162...12V. doi: 10.3847/1538-3881/abf932 . eISSN   1538-3881. ISSN   0004-6256.
  8. 1 2 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.
  9. 1 2 3 Kane, Stephen R.; Dalba, Paul A.; Li, Zhexing; Horch, Elliott P.; Hirsch, Lea A.; Horner, Jonathan; Wittenmyer, Robert A.; Howell, Steve B.; Everett, Mark E.; Butler, R. Paul; Tinney, Christopher G.; Carter, Brad D.; Wright, Duncan J.; Jones, Hugh R. A.; Bailey, Jeremy; O'Toole, Simon J. (5 June 2019). "Detection of Planetary and Stellar Companions to Neighboring Stars via a Combination of Radial Velocity and Direct Imaging Techniques". The Astronomical Journal. 157 (6): 252. arXiv: 1904.12931 . Bibcode:2019AJ....157..252K. doi: 10.3847/1538-3881/ab1ddf . eISSN   1538-3881.
  10. 1 2 Li, Yiting; Brandt, Timothy D.; Brandt, G. Mirek; Dupuy, Trent J.; Michalik, Daniel; Jensen-Clem, Rebecca; Zeng, Yunlin; Faherty, Jacqueline; Mitra, Elena L. (26 November 2021). "Precise Masses and Orbits for Nine Radial-velocity Exoplanets". The Astronomical Journal. 162 (6): 266. arXiv: 2109.10422 . Bibcode:2021AJ....162..266L. doi: 10.3847/1538-3881/ac27ab . eISSN   1538-3881. ISSN   0004-6256.
  11. 1 2 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.
  12. ↑ 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.
  13. ↑ "HR 8935". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved July 15, 2022.
  14. ↑ Feng, Fabo; Butler, R. Paul; et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series . 262 (21): 21. arXiv: 2208.12720 . Bibcode:2022ApJS..262...21F. doi: 10.3847/1538-4365/ac7e57 . S2CID   251864022.
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.