Astronomy:HD 102365

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Short description: Binary star system in the constellation Centaurus
HD 102365
Observation data
{{#ifeq:J2000|J2000.0 (ICRS)|Epoch J2000.0      Equinox J2000.0 (ICRS)| Epoch J2000      [[Astronomy:Equinox (celestial coordinates)|Equinox J2000}}
Constellation Centaurus
HD 102365 A
Right ascension  11h 46m 31.07253s[1]
Declination −40° 30′ 01.2859″[1]
Apparent magnitude (V) 4.88[2]
HD 102365 B
Right ascension  11h 46m 32.68988s[3]
Declination −40° 29′ 47.6048″[3]
Apparent magnitude (V) 15[4]
Characteristics
Spectral type G2V[5] + M4V[6]
U−B color index 0.10[2]
B−V color index 0.67[2]
Astrometry
HD 102365 A
Radial velocity (Rv)16.94±0.12[1] km/s
Proper motion (μ) RA: −1530.971[1] mas/yr
Dec.: +403.287[1] mas/yr
Parallax (π)107.3024 ± 0.0873[1] mas
Distance30.40 ± 0.02 ly
(9.319 ± 0.008 pc)
Absolute magnitude (MV)5.07[7]
HD 102365 B
Radial velocity (Rv)17.23±0.27[3] km/s
Proper motion (μ) RA: −1534.679 mas/yr
Dec.: +381.396 mas/yr
Parallax (π)107.4237 ± 0.0351[3] mas
Distance30.362 ± 0.010 ly
(9.309 ± 0.003 pc)
Details
A
Mass0.889[8] M
Radius0.96[8] R
Luminosity0.85[9] L
Surface gravity (log g)4.51[5] cgs
Temperature5,643[9] K
Metallicity [Fe/H]−0.28[9] dex
Rotational velocity (v sin i)0.5[10] km/s
Age4.5–5.7[11] Gyr
Other designations
CD−39°7301, GJ 442, HD 102365, HIP 57443, HR 4523, SAO 223020, G 66 Centauri, LHS 311, LTT 4373[12]
Database references
SIMBADA
B
ARICNSdata

HR 4523 (66 G. Centauri) is a binary star system that is located in the northeastern part of the Centaurus constellation, at a distance of about 30.4 light-years (9.3 parsecs) from the Solar System. The larger member of the system is a G-type star that is smaller than the Sun but of similar mass. It has a common proper motion companion that was discovered by W. J. Luyten in 1960.[6] This M-type star appears to be in a wide orbit around the primary at a current separation of about 211 astronomical units (AU),[6] (or 211 times the separation of the Earth from the Sun). By comparison, Neptune orbits at an average distance of 30 AU.

Description

The stellar classification for the primary star in this system is G2V;[5] the same as the Sun. That of the red dwarf companion is M4V.[6] The primary star has an estimated 86%[13] to 89% the mass of the Sun, 96% of the Sun's radius,[8] and 85% of the Sun's luminosity.[9] It is a slow rotator, with a projected rotational velocity of 0.5 km/s.[10] Age estimates range from 4.5 to 5.7 billion years (Gyr)[11] up to 7.1 Gyr[7] or 9.48 Gyr.[8] Compared to the Sun, it only has about 52%[14] of the abundance of elements other than hydrogen and helium; what astronomers term the metallicity of a star.

This star system has a relatively large proper motion.[12] The HR 4523 system is presently located within the Epsilon Indi Moving Group, although it gives itself away as an interloper, since the star is older and has a different composition than the group members.[15] It has space velocity components [U, V, W] = [−67, −40, +4] km/s.[16]

Planetary system

The primary star is believed to be orbited by a Neptune-like planet with a minimum mass 16 times that of the Earth. The orbital period of this planet is 122.1 days. No other planets have been discovered orbiting this star.[17] While a 2013 study was unable to confirm this planet,[18] it was confirmed by a 2023 study, with updated parameters.[19]:27

An examination of this system in the infrared did not reveal an excess emission that would otherwise suggest the presence of a circumstellar debris disk.[20]

The HD 102365 planetary system[17][19]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b ≥9.34+1.52
−1.5
 M
0.46±0.04 121.3±0.25 0.28±0.15

In popular culture

The couch gag for Bart's Not Dead in the television series The Simpsons has an alien family sitting on a couch in this star system. The adult male alien asks why Homer sounds like Walter Matthau.

References

  1. 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. 2.0 2.1 2.2 Feinstein, A. (1966), "Photoelectric observations of Southern late-type stars", The Information Bulletin for the Southern Hemisphere 8: 30, Bibcode1966IBSH....8...30F 
  3. 3.0 3.1 3.2 3.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  4. Poveda, A. et al. (April 1994), "Statistical studies of visual double and multiple stars. II. A catalogue of nearby wide binary and multiple systems", Revista Mexicana de Astronomía y Astrofísica 28 (1): 43–89, Bibcode1994RMxAA..28...43P 
  5. 5.0 5.1 5.2 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, doi:10.1086/504637, Bibcode2006AJ....132..161G 
  6. 6.0 6.1 6.2 6.3 Raghavan, Deepak et al. (September 2010), "A Survey of Stellar Families: Multiplicity of Solar-type Stars", The Astrophysical Journal Supplement 190 (1): 1–42, doi:10.1088/0067-0049/190/1/1, Bibcode2010ApJS..190....1R  For the adopted physical separation, see Table 11 in the appendix.
  7. 7.0 7.1 Holmberg, J.; Nordström, B.; Andersen, J. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics 501 (3): 941–947, doi:10.1051/0004-6361/200811191, Bibcode2009A&A...501..941H 
  8. 8.0 8.1 8.2 8.3 Takeda, Genya et al. (February 2007), "Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog", The Astrophysical Journal Supplement Series 168 (2): 297–318, doi:10.1086/509763, Bibcode2007ApJS..168..297T 
  9. 9.0 9.1 9.2 9.3 Porto de Mello, G.; del Peloso, E. F.; Ghezzi, L. (2006), "Astrobiologically Interesting Stars Within 10 Parsecs of the Sun", Astrobiology 6 (2): 308–331, doi:10.1089/ast.2006.6.308, PMID 16689649, Bibcode2006AsBio...6..308P 
  10. 10.0 10.1 Schröder, C.; Reiners, Ansgar; Schmitt, Jürgen H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo", Astronomy and Astrophysics 493 (3): 1099–1107, doi:10.1051/0004-6361:200810377, Bibcode2009A&A...493.1099S, http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/9690/aa10377-08.pdf?sequence=2 [yes|permanent dead link|dead link}}]
  11. 11.0 11.1 Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008), "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics", The Astrophysical Journal 687 (2): 1264–1293, doi:10.1086/591785, Bibcode2008ApJ...687.1264M 
  12. 12.0 12.1 "HD 102365". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+102365. 
  13. O'Toole, S. J. et al. (August 2009), "The Frequency of Low-Mass Exoplanets", The Astrophysical Journal 701 (2): 1732–1741, doi:10.1088/0004-637X/701/2/1732, Bibcode2009ApJ...701.1732O 
  14. For a metallicity of [Fe/H] = −0.28 dex, the proportion of metals is given by 10−0.28, or 52%.
  15. Kovacs, N.; Foy, R. (1978), "A detailed analysis of three stars in the Eggen's Epsilon INDI moving group", Astronomy and Astrophysics 68 (1–2): 27–31, Bibcode1978A&A....68...27K 
  16. Gliese, W. (1969), "Catalogue of Nearby Stars. Edition 1969", Veröffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 22, Karlsruhe, p. 1, Bibcode1969VeARI..22....1G 
  17. 17.0 17.1 Tinney, C. G. et al. (2011), "The Anglo-Australian Planet Search. XX. A Solitary Ice-giant Planet Orbiting HD 102365", The Astrophysical Journal 727 (2): 103, doi:10.1088/0004-637X/727/2/103, Bibcode2011ApJ...727..103T, http://eprints.usq.edu.au/20483/3/Tinney_Butler_Jones_etal_AJ_2011_SV.pdf 
  18. Zechmeister, M. et al. (April 2013). "The planet search programme at the ESO CES and HARPS. IV. The search for Jupiter analogues around solar-like stars". Astronomy & Astrophysics 552: A78. doi:10.1051/0004-6361/201116551. Bibcode2013A&A...552A..78Z. 
  19. 19.0 19.1 Laliotis, Katherine et al. (February 2023). "Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions". The Astronomical Journal 165 (4): 176. doi:10.3847/1538-3881/acc067. Bibcode2023AJ....165..176L. 
  20. Beichman, C. A. et al. (December 2006), "New Debris Disks around Nearby Main-Sequence Stars: Impact on the Direct Detection of Planets", The Astrophysical Journal 652 (2): 1674–1693, doi:10.1086/508449, Bibcode2006ApJ...652.1674B 

External links