# 19 Arietis

19 Arietis
Observation data
Epoch J2000      Equinox J2000
Constellation Aries
Right ascension  02h 13m 03.30440s[1]
Declination +15° 16′ 47.5005″[1]
5.70[2]
Characteristics
Spectral type M0 III[3]
U−B color index +1.95[2]
B−V color index +1.55[2]
R−I color index 0.97
Variable type Semiregular[4]
Astrometry
Radial velocity (Rv)21.11 ± 0.26[5] km/s
Proper motion (μ) RA: +97.95[1] mas/yr
Dec.: -20.30[1] mas/yr
Parallax (π)6.81 ± 0.38[1] mas
Distance480 ± 30 ly
(147 ± 8 pc)
Details
Temperature3,690[7] K
Metallicity [Fe/H]–0.02 ± 0.11[8] dex
Other designations
BD+14 357, FK5 1057, HD 13596, HIP 10328, HR 648, SAO 92841.[9]
Database references

19 Arietis (abbreviated 19 Ari) is a star in the northern constellation of Aries. 19 Arietis is the Flamsteed designation. It has an apparent visual magnitude of 5.70,[2] which means it is faintly visible to the naked eye. Based upon an annual parallax shift of 6.81 mas,[1] it is approximately 480 light-years (150 parsecs) away from Earth. At that distance, the brightness of the star is diminished by 0.21 in magnitude from extinction caused by interstellar gas and dust.[5]

This is a red giant star with a stellar classification of M0 III,[3] it is a semi-regular variable with periods of 32 and 275 days; the brightness of the star changes by an amplitude of 0.14 in magnitude during those intervals.[4] The measured angular diameter of this star, after correction for limb darkening, is 2.44 ± 0.03 mas.[10] At the estimated distance of Delta Ophiuchi,[1] this yields a physical size of about 39 times the radius of the Sun;[6] the effective temperature of the outer envelope is 3,690 K,[7] giving it the cool reddish glow of an M-type star.[11]

## References

1. van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
2. ^ a b c d 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. ^ a b 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, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
4. ^ a b Yeşilyaprak, C.; Aslan, Z. (December 2004), "Period-luminosity relation for M-type semiregular variables from Hipparcos parallaxes", Monthly Notices of the Royal Astronomical Society, 355 (2): 601–607, arXiv:0704.3150, Bibcode:2004MNRAS.355..601Y, doi:10.1111/j.1365-2966.2004.08344.x.
5. ^ a b Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272.
6. ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1.. The radius (R*) is given by:
{\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(147\cdot 2.44\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 77.2\cdot R_{\bigodot }\end{aligned}}}
7. ^ a b Wittkowski, M.; et al. (December 2006), "Tests of stellar model atmospheres by optical interferometry. IV. VINCI interferometry and UVES spectroscopy of Menkar", Astronomy and Astrophysics, 460 (3): 855–864, arXiv:astro-ph/0610150, Bibcode:2006A&A...460..855W, doi:10.1051/0004-6361:20066032.
8. ^ Taylor, B. J. (February 1999), "Catalogs of temperatures and [Fe/H] averages for evolved G and K stars", Astronomy and Astrophysics Supplement, 134: 523–524, Bibcode:1999A&AS..134..523T, doi:10.1051/aas:1999153.
9. ^ "19 Ari". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-18.
10. ^ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431: 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.
11. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on March 10, 2012, retrieved 2012-01-16