HD 75289

HD 75289 is a faint double star in the southern constellation of Vela. The primary component has a yellow hue and an apparent visual magnitude of 6.35.[2] Under exceptionally good circumstances it might be visible to the unaided eye; however, usually binoculars are needed. The pair are located at a distance of 95 light years from the Sun based on parallax, and are drifting further away with a radial velocity of +10 km/s.[6]

HD 75289
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Vela
HD 75289 A
Right ascension 08h 47m 40.3896s[1]
Declination −41° 44′ 12.4563″[1]
Apparent magnitude (V) 6.35[2]
B
Right ascension 08h 47m 42.2616s[3]
Declination −41° 44′ 07.4408″[3]
Apparent magnitude (V) 11.80[4]
Characteristics
Evolutionary stage Main sequence
Spectral type G0V[2] + M2-M5V[5]
B−V color index 0.578[2]
Astrometry
A
Radial velocity (Rv)+9.90±0.64[6] km/s
Proper motion (μ) RA: −20.509±0.051[1] mas/yr
Dec.: −227.945±0.054[1] mas/yr
Parallax (π)34.3167 ± 0.0281[1] mas
Distance95.04 ± 0.08 ly
(29.14 ± 0.02 pc)
Absolute magnitude (MV)4.04[2]
B
Proper motion (μ) RA: −13.817±0.194[3] mas/yr
Dec.: −229.657±0.230[3] mas/yr
Parallax (π)34.1784 ± 0.1208[3] mas
Distance95.4 ± 0.3 ly
(29.3 ± 0.1 pc)
Details[7]
A
Mass1.141+0.020
−0.035 M☉
Radius1.298±0.013 R☉
Luminosity1.99[2] L☉
Surface gravity (log g)4.317±0.680 cgs
Temperature6,184±43 K
Metallicity [Fe/H]0.32±0.08 dex
Rotation~15.95 d[2]
Rotational velocity (v sin i)2.978±0.722 km/s
Age4.410+0.757
−0.337 Gyr
B
Mass0.135±0.003[5] M☉
Other designations
CD−41°4507, HD 75289, HIP 43177, HR 3497, SAO 220481, WDS J08477-4144[8]
Database references
SIMBADdata

The brighter member, component A, is a G-type main-sequence star like the Sun with a stellar classification of G0V. In 1982 it was classified as a supergiant, but this proved erroneous. It has an age comparable to the Sun and is considered metal-rich, with a greater abundance of heavier elements compared to the Sun.[2] The star has 14% more mass than the Sun and a 30% greater girth. It is spinning with a projected rotational velocity of 3 km/s,[7] giving it a ~16 day rotation period. The star is radiating double[2] the luminosity of the Sun from its photosphere at an effective temperature of 6,184 K.[7]

In 2004, a co-moving stellar companion was identified, based on an earlier suggestion from 2001. Designated component B, this red dwarf star lies at an angular separation of 21.5″, corresponding to a projected separation of 621 AU. However, the radial distance between the stars is unknown, so they are probably further apart. In any case, one revolution around the primary would take thousands of years to complete. The study that found the red dwarf also rules out any further stellar companions beyond 140 AU and massive brown dwarf companions from 400 AU up to 2,000 AU.[5]

Planetary system

In 1999 a exoplanet HD 75289 b with half the mass of Jupiter was detected orbiting the primary by radial velocity method.[2] This exoplanet is a typical hot Jupiter that takes only about 3.51 days to revolve at an orbital distance of 0.0482 AU.

The HD 75289 planetary system[9]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥0.456±0.010 MJ 0.047859±0.000002 3.50916±0.00002 0.062±0.022 — —

References
  1. 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.
  2. Udry, S.; et al. (2000). "The CORALIE survey for southern extra-solar planets II. The short-period planetary companions to HD 75289 and HD 130322". Astronomy and Astrophysics. 356 (2): 590–598. Bibcode:2000A&A...356..590U. S2CID 2048031.
  3. 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.
  4. Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Cite journal requires |journal= (help)
  5. Mugrauer, M.; et al. (2004). "A low-mass stellar companion of the planet host star HD 75289". Astronomy and Astrophysics. 425: 249–253. arXiv:astro-ph/0406108. Bibcode:2004A&A...425..249M. doi:10.1051/0004-6361:20041009.
  6. Valenti, J. A.; Fischer, D. A. (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: 141–166. Bibcode:2005ApJS..159..141V. doi:10.1086/430500.
  7. Soto, M. G.; Jenkins, J. S. (July 2018). "Spectroscopic Parameters and atmosphEric ChemIstriEs of Stars (SPECIES). I. Code description and dwarf stars catalogue". Astronomy & Astrophysics. 615: 28. arXiv:1801.09698. Bibcode:2018A&A...615A..76S. doi:10.1051/0004-6361/201731533. A76. Note: HARPS values used here.
  8. "HD 75289". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-06.
  9. Wittenmyer, Robert A.; et al. (2020). "Cool Jupiters greatly outnumber their toasty siblings: occurrence rates from the Anglo-Australian Planet Search". Monthly Notices of the Royal Astronomical Society. 492 (1): 377–383. arXiv:1912.01821. Bibcode:2020MNRAS.492..377W. doi:10.1093/mnras/stz3436. S2CID 208617606.

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