HD 34445

Last updated • 2 min readFrom Wikipedia, The Free Encyclopedia
HD 34445
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Orion
Right ascension 05h 17m 40.9804s [1]
Declination +07° 21′ 12.0548″ [1]
Apparent magnitude  (V)7.31±0.03 [2]
Characteristics
Spectral type G0 V [2]
B−V color index 0.661 ± 0.015 [2]
Astrometry
Radial velocity (Rv)−78.906±0.0082 [3]  km/s
Proper motion (μ)RA: −0.811±0.076 [1]   mas/yr
Dec.: −146.997±0.061 [1]   mas/yr
Parallax (π)21.6675 ± 0.0464  mas [1]
Distance 150.5 ± 0.3  ly
(46.15 ± 0.10  pc)
Absolute magnitude  (MV)4.04±0.10 [2]
Details
Mass 1.07±0.02 [2]   M☉
Radius 1.38±0.08 [2]   R☉
Luminosity 2.01 ± 0.2 [2]   L☉
Surface gravity (log g)4.21 ± 0.08 [2]   cgs
Temperature 5836 ± 44 [2]   K
Metallicity [Fe/H]+0.14±0.04 dex [2]
+0.24±0.04 [4]   dex
Rotation ~22 d, [5] ~52 d [6]
Rotational velocity (v sin i)2.7±0.5 [2]  km/s
Age 8.5±2.0 [2]   Gyr
Other designations
BD+07° 855, HD  34445, HIP  24681, SAO  112601 [7]
Database references
SIMBAD data
Exoplanet Archive data

HD 34445 is a star in the equatorial constellation of Orion. With an apparent visual magnitude of 7.31, [2] it is a 7th magnitude star that is too dim to be readily visible to the naked eye. The system is located at a distance of 150.5  light years from the Sun based on parallax measurements, but is drifting closer with a high radial velocity of −79 km/s. [3] It is expected to draw as close as 57.5 light-years in ~492,000 years. [8]

Contents

This is an ordinary G-type main-sequence star with a stellar classification of G0 V, [2] which means it is a Sun-like star that is generating energy through core hydrogen fusion. It is considered a metal-rich star, [4] showing a much higher metallicity compared to the Sun. Despite this it is an older star and chromospherically quiet, lying about 0.8 magnitudes above the main sequence. This star is larger, hotter, brighter, and more massive than the Sun. It is spinning with a projected rotational velocity of ~3 km/s, giving it a rotation period of around 22 days. [2]

Planetary companions

In 2004, a gas giant was found in orbit around the star, but it was not until 2009 that this planet was confirmed. [5] In 2017, five more planets were found. [2] All have minimum masses significantly greater than that of the Earth, between 16.8 ME and 200.0 ME. [2] The system as configured appears to be dynamically stable. [9]

A 2021 study was only able to confirm HD 34445 b as a planet. HD 34445 e was found to likely be an artifact of the stellar rotation, as its orbital period closely matched to the rotation period of the star, HD 34445 c & d were also found to likely be false positives having orbital periods of around 1⁄4 and 1⁄3 of a year, and HD 34445 f was not detected. [6]

The HD 34445 planetary system [2]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
e(unconfirmed)≥0.0529 ± 0.0089 MJ 0.2687 ± 0.001949.175 ± 0.0450.090 ± 0.062——
d(unconfirmed)≥0.097 ± 0.13 MJ 0.4817 ± 0.0033117.87 ± 0.180.027 ± 0.051——
c(unconfirmed)≥0.168 ± 0.016 MJ 0.7181 ± 0.0049214.67 ± 0.450.036 ± 0.071——
f(unconfirmed)≥0.119 ± 0.021 MJ 1.543 ± 0.016676.8 ± 7.90.031 ± 0.057——
b ≥0.629 ± 0.028  MJ 2.075 ± 0.0161056.7 ± 4.70.014 ± 0.035——
g(unconfirmed)≥0.38 ± 0.13 MJ 6.36 ± 1.025700 ± 15000.032 ± 0.080——

See also

Related Research Articles

HD 169830 is a star in the southern constellation of Sagittarius. It has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of +5.90. The star is located at a distance of 120 light years from the Sun based on parallax. It is drifting closer with a radial velocity of −17.3 km/s, and is predicted to come as close as 20.7 ly (6.4 pc) in 2.08 million years. HD 169830 is known to be orbited by two large Jupiter-like exoplanets.

HD 114783 is a star with two exoplanetary companions in the equatorial constellation of Virgo. With an apparent visual magnitude of 7.56 it is too faint to be visible with the unaided eye, but is an easy target for binoculars. Based on parallax measurements, it is located at a distance of 68.6 light-years from the Sun, but is drifting closer with a radial velocity of −12 km/s.

HD 107148 is a wide binary star system in the constellation of Virgo. A pair of exoplanets have been confirmed in orbit around the brighter star. This system is located at a distance of 161 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of 25.2 K. Although having an absolute magnitude of 4.47, at that range the system is too faint to be visible with the naked eye, having an apparent visual magnitude of 8.01.

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 222582 is a multiple star system in the equatorial constellation of Aquarius. It is invisible to the naked eye with an apparent visual magnitude of 7.7, but can be viewed with binoculars or a small telescope. The system is located at a distance of 137 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of +12 km/s. It is located close enough to the ecliptic that it is subject to lunar occultations.

HD 11506 is a star in the equatorial constellation of Cetus. It has a yellow hue and can be viewed with a small telescope but is too faint to be visible to the naked eye, having an apparent visual magnitude of 7.51. The distance to this object is 167 light-years based on parallax, but it is drifting closer to the Sun with a radial velocity of −7.5 km/s. It has an absolute magnitude of 3.94.

HD 43691 is a star with an orbiting exoplanet in the constellation Auriga. With an apparent visual magnitude of 8.03, it is too faint to be visible to the naked eye. This system is located at a distance of 279 light years based on parallax measurements, but is drifting closer with a heliocentric radial velocity of −29 km/s.

HD 33564 is a single star with an exoplanetary companion in the northern constellation of Camelopardalis. It has an apparent visual magnitude of 5.08, which means it is a 5th magnitude star that is faintly visible to the naked eye. The system is located at a distance of 68 light years from the Sun based on parallax, and it is drifting closer with a radial velocity of −11 km/s. It is a candidate member of the Ursa Major Moving Group.

HD 190647 is a yellow-hued star with an exoplanetary companion, located in the southern constellation of Sagittarius. It has an apparent visual magnitude of 7.78, making this an 8th magnitude star that is much too faint to be readily visible to the naked eye. The star is located at a distance of 178 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −40 km/s. It is also called HIP 99115.

HD 4113 is a dual star system in the southern constellation of Sculptor. It is too faint to be viewed with the naked eye, having an apparent visual magnitude of 7.88. The distance to this star, as estimated by parallax measurements, is 137 light years. It is receding away from the Sun with a radial velocity of +5 km/s.

HD 73256 is a variable star in the southern constellation of Pyxis. It has the variable star designation CS Pyxidis. With a baseline apparent visual magnitude of 8.08, it requires binoculars or a small telescope to view. The star is located at a distance of 120 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +30 km/s.

HD 118203 is a star with an orbiting exoplanet located in the northern circumpolar constellation of Ursa Major. It has the proper name Liesma, which means flame, and it is the name of a character from the Latvian poem Staburags un Liesma. The name was selected in the NameExoWorlds campaign by Latvia, during the 100th anniversary of the IAU.

HD 45364 is a star in the southern constellation of Canis Major. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 8.08. The distance to this system is 112 light years based on parallax. It is drifting further away from the Sun with a radial velocity of +16.4 km/s, having come within 49 light-years some 1.5 million years ago.

HD 179079 is a star with an exoplanetary companion in the equatorial constellation of Aquila. It has an apparent visual magnitude of approximately 7.96, making it too faint to be readily visible to the naked eye. The distance to this star can be determine using parallax measurements, which yields an estimate of approximately 228 light years. It is drifting further away with a radial velocity of +20 km/s.

HD 171238 is a star with an orbiting exoplanet in the southern constellation of Sagittarius. It is located at a distance of 145 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of 21 km/s. The star has an absolute magnitude of 5.15, but at the distance of this system it is too faint to be viewed with the naked eye, having an apparent visual magnitude of 8.61.

HD 126614 is a trinary star system in the equatorial constellation of Virgo. The primary member, designated component A, is host to an exoplanetary companion. With an apparent visual magnitude of 8.81, it is too faint to be seen with the naked eye. The system is located at a distance of 239 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −33 km/s.

Gliese 179 is a small red dwarf star with an exoplanetary companion in the equatorial constellation of Orion. It is much too faint to be visible to the naked eye with an apparent visual magnitude of 11.94. The system is located at a distance of 40.5 light-years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of –9 km/s. It is a high proper motion star, traversing the celestial sphere at an angular rate of 0.370″·yr−1.

HD 79498 is a double star in the northern constellation of Cancer. The primary component of this pair has an orbiting exoplanet companion. This star is too faint to be viewed with the naked eye, having an apparent visual magnitude of 8.05. The system is located at a distance of 159 light years based on parallax measurements, and is drifting further away with a heliocentric radial velocity of 20 km/s. It has a relatively high proper motion, traversing the celestial sphere at an angular rate of 0.2″·yr−1.

HD 220689 is a single star in the equatorial constellation of Aquarius. It is a challenge to view with the naked eye, having an apparent visual magnitude of +7.74, but is readily viewed with a pair of binoculars. The star is located at a distance of 153 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +12 km/s. A survey in 2015 has ruled out the existence of any additional stellar companions at projected distances from 26 to 305 astronomical units.

HD 121056, or HIP 67851, is an aging giant star with a pair of orbiting exoplanets located in the southern constellation of Centaurus. This star is dimly visible to the naked eye with an apparent visual magnitude of 6.17. It is located at a distance of 209 light years from the Sun, based on parallax measurements, and is drifting further away with a radial velocity of 5.6 km/s.

References

  1. 1 2 3 4 5 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. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Vogt, Steven S.; et al. (2017). "A Six-planet System around the Star HD 34445". The Astronomical Journal. 154 (5): 181. arXiv: 1710.07337 . Bibcode:2017AJ....154..181V. doi: 10.3847/1538-3881/aa8b61 . S2CID   119182115.
  3. 1 2 Soubiran, C.; et al. (2013). "The catalogue of radial velocity standard stars for Gaia. I. Pre-launch release". Astronomy and Astrophysics. 552. A64. arXiv: 1302.1905 . Bibcode:2013A&A...552A..64S. doi:10.1051/0004-6361/201220927. S2CID   56094559.
  4. 1 2 Sousa, S. G.; et al. (November 2006). "Spectroscopic parameters for a sample of metal-rich solar-type stars". Astronomy and Astrophysics. 458 (3): 873–880. Bibcode:2006A&A...458..873S. doi: 10.1051/0004-6361:20065658 .
  5. 1 2 Howard, Andrew W.; et al. (2010). "The California Planet Survey. I. Four New Giant Exoplanets". The Astrophysical Journal. 721 (2): 1467–1481. arXiv: 1003.3488 . Bibcode:2010ApJ...721.1467H. doi:10.1088/0004-637X/721/2/1467. S2CID   14147776.
  6. 1 2 Rosenthal, Lee J.; Fulton, Benjamin J.; Hirsch, Lea A.; Isaacson, Howard T.; Howard, Andrew W.; Dedrick, Cayla M.; Sherstyuk, Ilya A.; Blunt, Sarah C.; Petigura, Erik A.; Knutson, Heather A.; Behmard, Aida; Chontos, Ashley; Crepp, Justin R.; Crossfield, Ian J. M.; Dalba, Paul A.; Fischer, Debra A.; Henry, Gregory W.; Kane, Stephen R.; Kosiarek, Molly; Marcy, Geoffrey W.; Rubenzahl, Ryan A.; Weiss, Lauren M.; Wright, Jason T. (2021). "The California Legacy Survey. I. A Catalog of 178 Planets from Precision Radial Velocity Monitoring of 719 Nearby Stars over Three Decades". The Astrophysical Journal Supplement Series. 255 (1): 8. arXiv: 2105.11583 . Bibcode:2021ApJS..255....8R. doi: 10.3847/1538-4365/abe23c . S2CID   235186973.
  7. ↑ "HD 34445". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 19 November 2017.
  8. ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID   119257644.
  9. ↑ Georgakarakos, Nikolaos; Dobbs-Dixon, Ian (September 2019). "Do the planets in the HD 34445 system really exist?". Monthly Notices of the Royal Astronomical Society. 488 (3): 3818–3825. arXiv: 1907.05495 . Bibcode:2019MNRAS.488.3818G. doi: 10.1093/mnras/stz1945 .
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.