Mu Horologii

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Mu Horologii
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Horologium
Right ascension 03h 03m 36.81891s [1]
Declination −59° 44′ 15.9925″ [1]
Apparent magnitude  (V) 5.11 [2]
Characteristics
Spectral type F0 III/IV [3]
B−V color index +0.34 [2]
Astrometry
Radial velocity (Rv)17.3±2.8 [4] km/s
Proper motion (μ)RA: −73.29 [1]   mas/yr
Dec.: −64.06 [1]   mas/yr
Parallax (π)23.04 ± 0.16 [1] mas
Distance 141.6 ± 1.0 ly
(43.4 ± 0.3 pc)
Absolute magnitude  (MV)1.99 [5]
Details
Mass 1.53+0.08
−0.01 [6]   M☉
Luminosity 13 [7]   L☉
Surface gravity (log g)3.80±0.02 [6]   cgs
Temperature 6,898±63 [6]   K
Metallicity [Fe/H]−0.42±0.05 [6]   dex
Rotational velocity (v sin i)79.2±4.0 [5]  km/s
Age 1.95+0.20
−0.14 [6]   Gyr
Other designations
μ Hor, CPD−60° 236, HD  19319, HIP  14240, HR  934, SAO  232981 [8]
Database references
SIMBAD data

Mu Horologii (μ Horologii) is a solitary, [9] yellow-white hued star in the southern constellation of Horologium. It is faintly visible to the naked eye with an apparent visual magnitude of 5.11. [2] Based upon an annual parallax shift of 23.04  mas as seen from Earth, [1] it is located about 141.6  light years from the Sun.

Star An astronomical object consisting of a luminous spheroid of plasma held together by its own gravity

A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, the brightest of which gained proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. However, most of the estimated 300 sextillion (3×1023) stars in the Universe are invisible to the naked eye from Earth, including all stars outside our galaxy, the Milky Way.

Horologium (constellation) constellation in the southern celestial hemisphere

Horologium is a faint constellation in the southern sky. It was devised by French astronomer Nicolas Louis de Lacaille in 1752, and it remains one of the 88 modern constellations. The constellation's brightest star is Alpha Horologii, an orange giant. R Horologii is a red giant Mira variable with one of the widest ranges in brightness known. Three star systems have exoplanets, while Nu Horologii has a debris disk.

Stellar parallax apparent shift of position of a nearby star against the background of distant objects during Earths orbital period

Stellar parallax is the apparent shift of position of any nearby star against the background of distant objects. Created by the different orbital positions of Earth, the extremely small observed shift is largest at time intervals of about six months, when Earth arrives at exactly opposite sides of the Sun in its orbit, giving a baseline distance of about two astronomical units between observations. The parallax itself is considered to be half of this maximum, about equivalent to the observational shift that would occur due to the different positions of Earth and the Sun, a baseline of one astronomical unit (AU).

This is an evolving F-type star with a stellar classification of F0 III/IV, [3] showing mixed traits of a subgiant and a giant star. It is around two billion years old with a projected rotational velocity of 79.2 km/s. [5] The star has 1.5 [6] times the mass of the Sun and is radiating 13 [7] times the solar luminosity from its photosphere at an effective temperature of 6,898 K. [6]

Stellar evolution Changes to a star over its lifespan

Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.

Stellar classification Classification of stars based on their spectral characteristics

In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element or molecule, with the line strength indicating the abundance of that element. The strengths of the different spectral lines vary mainly due to the temperature of the photosphere, although in some cases there are true abundance differences. The spectral class of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature.

Giant star type of star with a radius 10-100 times, and luminosity 10-1000x that of the Sun

A giant star is a star with substantially larger radius and luminosity than a main-sequence star of the same surface temperature. They lie above the main sequence on the Hertzsprung–Russell diagram and correspond to luminosity classes II and III. The terms giant and dwarf were coined for stars of quite different luminosity despite similar temperature or spectral type by Ejnar Hertzsprung about 1905.

Related Research Articles

Tau Sculptoris is a binary star system in the southern constellation of Sculptor, about 8° to the east-southeast of Rasalgethi. It is faintly visible to the naked eye with a combined apparent visual magnitude of +5.69. Based upon an annual parallax shift of 14.42 mas as seen from Earth, it is located around 230 light years from the Sun.

Psi Tauri is a solitary, yellow-white hued star in the zodiac constellation of Taurus. It is an F-type main sequence star with a stellar classification of F1 V. The star is about 1.4 billion years old with 1.6 times the mass of the Sun and is radiating 4.8 times the Sun's luminosity from its photosphere at an effective temperature of 7,088 K. It is visible to the naked eye with an apparent visual magnitude of +5.22. The distance to this system, as determined using an annual parallax shift of 36.23 mas as seen from the Earth, is 90 light years.

Kappa Trianguli Australis Variable star in the constellation Triangulum Australe

Kappa Trianguli Australis is a star in the constellation Triangulum Australe.

39 Aurigae is a single star in the constellation of Auriga. The designation is from the star catalogue of English astronomer John Flamsteed, first published in 1712. The star is just barely visible to the naked eye, having an apparent visual magnitude of 5.90. Based upon an annual parallax shift of 20.11 mas as seen from Earth, it is located 112 light years away. 5 Andromedae is moving further from the Sun with a radial velocity of +34 km/s. It has a relatively high proper motion, advancing across the celestial sphere at the rate of 0.151 arc seconds per year.

Mu2 Cancri is a solitary, yellow-hued star in the zodiac constellation of Cancer. It is visible to the naked eye with an apparent visual magnitude of +5.30. Based upon an annual parallax shift of 42.94 mas as seen from Earth, this star is located around 76.0 light years from the Sun. Mu2 Cancri will make its closest approach in about 600,000 years when it passes at a distance of 4.9 pc (16 ly).

Sigma2 Cancri, Latinized from σ2 Cancri, is the Bayer designation for a solitary, white-hued star in the constellation Cancer. It is faintly visible to the naked eye, with an apparent visual magnitude of +5.44. Based upon an annual parallax shift of 16.79 mas as seen from Earth, this star is located around 194 light years from the Sun.

Alpha Horologii is a solitary orange-hued giant star in the constellation Horologium. It is visible to the naked eye with an apparent visual magnitude of +3.85. Based upon an annual parallax shift of 28.36 mas as seen from the Earth, it is located 115.0±0.5 light-years from the Sun. The star is moving away from the Sun with a radial velocity of +21.6 km/s.

HD 49878 is a single star in the northern circumpolar constellation of Camelopardalis.

Sigma Columbae, Latinized from σ Columbae, is a solitary, yellow-white hued star in the southern constellation of Columba. It is faintly visible to the naked eye with an apparent visual magnitude of 5.51. Based upon an annual parallax shift of 1.96 mas as seen from Earth, this star is located roughly 1,700 light years from the Sun.

Beta Horologii, Latinized from β Horologii, is the third-brightest star in the southern constellation of Horologium. It is faintly visible to the naked eye with an apparent visual magnitude of 4.98. Based upon an annual parallax shift of 11.07 mas as seen from Earth, it is located about 295 light years from the Sun. The star is moving away with a radial velocity of +24 km/s.

Epsilon Pyxidis Star in the constellation Pyxis

Epsilon Pyxidis (ε Pyxidis) is quadruple star system in the southern constellation of Pyxis. It is faintly visible to the naked eye, having a combined apparent visual magnitude of +5.60. Based upon an annual parallax shift of 15.39 mas as seen from Earth, it is located around 212 light years from the Sun. The system is deemed to be a member of the Sirius supercluster of stars that share a common motion through space.

φ Eridani is a star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.55. The distance to this star, as determined using the parallax method, is around 154 light years.

Delta Horologii is a binary star system in the constellation Horologium. It is visible to the naked eye with a combined apparent visual magnitude of 4.93. As of 2014, the pair had an angular separation of 0.20 arc seconds along a position angle of 24°. Based upon an annual parallax shift of 18.24 mas as seen from Earth, it is located about 179 light years from the Sun.

Omicron Lupi is a binary star in the southern constellation of Lupus. It is a visible to the naked eye with a combined apparent visual magnitude of 4.323. Based upon an annual parallax shift of 8.07 mas as seen from Earth, it is located around 400 light years from the Sun, give or take 30 light years. At that distance, the visual magnitude of the system is diminished by an extinction factor of 0.13±0.01 due to interstellar dust. It is a member of the Upper Centaurus Lupus subgroup of the nearby Scorpius–Centaurus Association.

Phi2 Lupi, Latinized from φ2 Lupi, is a solitary star in the southern constellation of Lupus. With an apparent magnitude of 4.535, it is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 6.28 mas as seen from Earth, it is located around 520 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.052±0.013 due to interstellar dust. It is a member of the Upper Centaurus-Lupus subgroup of the Scorpius–Centaurus Association.

HD 125442 is a single star in the southern constellation of Lupus. Its apparent visual magnitude is 4.78, which can be seen with the naked eye. The distance to HD 125442, as determined from its annual parallax shift of 22.1 mas, is 147 light years.

Eta Horologii is a binary star system in the southern constellation of Horologium. It is visible to the naked eye with a combined apparent visual magnitude of 5.31. Based upon an annual parallax shift of 21.95 mas as seen from Earth, it is located around 149 light years from the Sun.

Nu Leporis, Latinized from ν Leporis, is a probable astrometric binary star system in the constellation Lepus. It is visible to the naked eye as a faint star with an apparent visual magnitude of 5.29. Based upon an annual parallax shift of 7.70 mas as seen from the Earth, it is 420 light years from the Sun.

γ Horologii, Latinised as Gamma Horologii, is a solitary, yellow-hued giant/subgiant star in the southern constellation of Horologium. Located 183 ± 2 light-years from Earth, it shines with a luminosity approximately 16 times that of the Sun and has a surface temperature of 5,175 K.

Kappa Crateris Star in the constellation Crater

Kappa Crateris (κ Crateris) is the Bayer designation for a star in the southern constellation of Crater. It has an apparent visual magnitude of 5.94, which, according to the Bortle scale, can be seen with the naked eye under dark suburban skies. The distance to this star, as determined from an annual parallax shift of 14.27 mas, is around 229 light years.

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv: 0708.1752  Lock-green.svg, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. 1 2 3 Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J.
  3. 1 2 Houk, Nancy; Cowley, A. P. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 1, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1975mcts.book.....H.
  4. ↑ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv: 1208.3048  Lock-green.svg, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  5. 1 2 3 Ammler-von Eiff, M.; Reiners, A. (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: 31, arXiv: 1204.2459  Lock-green.svg, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, A116.
  6. 1 2 3 4 5 6 7 Ramírez, I.; et al. (September 2012), "Lithium Abundances in nearby FGK Dwarf and Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, and Exoplanets", The Astrophysical Journal, 756 (1): 46, arXiv: 1207.0499  Lock-green.svg, Bibcode:2012ApJ...756...46R, doi:10.1088/0004-637X/756/1/46.
  7. 1 2 McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv: 1208.2037  Lock-green.svg, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  8. ↑ "mu. Hor". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2017-04-25.
  9. ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society , 389 (2): 869–879, arXiv: 0806.2878  Lock-green.svg, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
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