HD 74156

Last updated
HD 74156
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Hydra
Right ascension 08h 42m 25.12195s [1]
Declination +04° 34′ 41.1457″ [1]
Apparent magnitude  (V)+7.614 [2]
Characteristics
Spectral type G0V
U−B color index  ?
B−V color index 0.581 [2]
V−R color index 0.4
R−I color index 0.2
Variable type “None”
Astrometry
Radial velocity (Rv)3.90±0.13 [1]  km/s
Proper motion (μ)RA: 24.666±0.025  mas/yr [1]
Dec.: −200.238±0.019  mas/yr [1]
Parallax (π)17.4242 ± 0.0247  mas [1]
Distance 187.2 ± 0.3  ly
(57.39 ± 0.08  pc)
Absolute magnitude  (MV)+3.57 ± 0.15
Details
Mass 1.24 [2]   M☉
Radius 1.64 ± 0.19 [2]   R☉
Luminosity (bolometric)3.037 ± 0.485 [2]   L☉
Surface gravity (log g)4.4 ± 0.15 [2]   cgs
Temperature 5960 ± 100 [2]   K
Metallicity [Fe/H]+0.13 [2]   dex
Rotational velocity (v sin i)4.3 [2]  km/s
Age 3.7 ± 0.4 [2]   Gyr
Other designations
HIP 42723, SAO 117040, BD+05 2035, 2MASS J08422511+0434411
Database references
SIMBAD data

HD 74156 is a yellow dwarf star (spectral type G0V) in the constellation of Hydra, 187 light years from the Solar System. [1] It is known to be orbited by two giant planets.

Contents

Star

This star is 24% more massive and 64% larger than the Sun. The total luminosity is 2.96 times that of the Sun and its temperature 5960 K. [2] The age of the star is estimated at 3.7 billion years, [2] with metallicity 1.35 times that of the Sun based on its abundance of iron.

Planetary system

In April 2001, two giant planets were announced orbiting the star. [3] [4] The first planet HD 74156 b orbits the star at a distance closer than Mercury is to the Sun, in an extremely eccentric orbit. The second planet HD 74156 c is a long-period, massive planet (at least 8 times the mass of Jupiter), which orbits the star in an elliptical orbit with a semimajor axis of 3.90 astronomical units. [2] In 2022, the inclination and true mass of HD 74156 c were measured via astrometry. [5]

The HD 74156 planetary system [6] [5]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥1.778±0.020  MJ 0.2916±0.003351.6385±0.00150.6380±0.0061——
c 8.665+1.385
−0.470  MJ 		3.678+0.145
−0.159		2448.5±4.20.377±0.006120.162+7.601
−66.225 ° 		—

Claims of a third planet

Given the two-planet configuration of the system under the assumption that the orbits are coplanar and have masses equal to their minimum masses, an additional Saturn-mass planet would be stable in a region between 0.9 and 1.4 AU between the orbits of the two known planets. [7] Under the "packed planetary systems" hypothesis, which predicts that planetary systems form in such a way that the system could not support additional planets between the orbits of the existing ones, the gap would be expected to host a planet.

In September 2007, a third planet with a mass at least 0.396 Jupiter masses was announced to be orbiting between planets b and c with an eccentric orbit. [8] The planet, orbiting in a region of the planetary system previously known to be stable for additional planets, was seen as a confirmation of the "packed planetary systems" hypothesis. [9] However, Roman V. Baluev has cast doubt on this discovery, suggesting that the observed variations may be due to annual errors in the data. [10] A subsequent search using the Hobby-Eberly Telescope also failed to confirm the planet, [11] and further data obtained using HIRES instrument strongly contradicts its existence. [2]

See also

Related Research Articles

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References

  1. 1 2 3 4 5 6 7 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. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Meschiari, Stefano; et al. (2011). "The Lick-Carnegie Survey: Four New Exoplanet Candidates". The Astrophysical Journal. 727 (2). 117. arXiv: 1011.4068 . Bibcode:2011ApJ...727..117M. doi:10.1088/0004-637X/727/2/117. S2CID   59065004.
  3. ↑ "Exoplanets: The Hunt Continues!" (Press release). Garching, Germany: European Southern Observatory. April 4, 2001. Retrieved December 27, 2012.
  4. ↑ Naef, Dominique; Mayor, Michel; Beuzit, Jean-Luc; Perrier, Christian; Queloz, Didier; Sivan, Jean-Pierre; Udry, Stéphane (2004). "The ELODIE survey for northern extra-solar planets. III. Three planetary candidates detected with ELODIE" (PDF). Astronomy and Astrophysics . 414 (1): 351–359. arXiv: astro-ph/0310261 . Bibcode:2004A&A...414..351N. doi:10.1051/0004-6361:20034091. S2CID   16603563.
  5. 1 2 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.
  6. ↑ Feng, Y. Katherina; et al. (2015). "The California Planet Survey IV: A Planet Orbiting the Giant Star HD 145934 and Updates to Seven Systems with Long-period Planets". The Astrophysical Journal. 800 (1). 22. arXiv: 1501.00633 . Bibcode:2015ApJ...800...22F. doi:10.1088/0004-637X/800/1/22. S2CID   56390823.
  7. ↑ Sean N. Raymond; Rory Barnes (2005). "Predicting Planets in Known Extrasolar Planetary Systems. II. Testing for Saturn Mass Planets". The Astrophysical Journal. 619 (1): 549–557. arXiv: astro-ph/0404211 . Bibcode:2005ApJ...619..549R. doi:10.1086/426311. S2CID   13015545.
  8. ↑ Jacob L. Bean; et al. (2008). "Detection of a Third Planet in the HD 74156 System Using the Hobby-Eberly Telescope". The Astrophysical Journal. 672 (2): 1202–1208. arXiv: 0709.1656 . Bibcode:2008ApJ...672.1202B. doi:10.1086/523701. hdl:2152/35107. S2CID   15507937.
  9. ↑ Barnes, Rory; et al. (2008). "The Successful Prediction of the Extrasolar Planet HD 74156 d". The Astrophysical Journal Letters. 680 (1): L57–L60. arXiv: 0804.4496 . Bibcode:2008ApJ...680L..57B. doi:10.1086/589712. S2CID   14070540.
  10. ↑ Baluev, Roman V. (2008). "Accounting for velocity jitters in planet search surveys". Monthly Notices of the Royal Astronomical Society . 393 (3): 969–978. arXiv: 0712.3862 . Bibcode:2009MNRAS.393..969B. doi:10.1111/j.1365-2966.2008.14217.x. S2CID   15170720.
  11. ↑ Wittenmyer, Robert A.; Endl, Michael; Cochran, William D.; Levison, Harold F.; Henry, Gregory W. (2009). "A Search for Multi-Planet Systems Using the Hobby-Eberly Telescope". The Astrophysical Journal Supplement. 182 (1): 97–119. arXiv: 0903.0652 . Bibcode:2009ApJS..182...97W. doi:10.1088/0067-0049/182/1/97. S2CID   7422668.
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