# 15 Arietis

15 Arietis
Observation data
Epoch J2000      Equinox J2000
Constellation Aries
Right ascension 02h 10m 37.59642s[1]
Declination +19° 30′ 01.2099″[1]
5.67 - 5.74[2]
Characteristics
Spectral type M3 III[3]
U−B color index +1.91[4]
B−V color index +1.64[4]
Variable type SRs[2]
Astrometry
Radial velocity (Rv)+62.04 ± 0.22[5] km/s
Proper motion (μ) RA: +87.88[1] mas/yr
Dec.: -27.82[1] mas/yr
Parallax (π)5.84 ± 0.49[1] mas
Distance560 ± 50 ly
(170 ± 10 pc)
Absolute magnitude (MV)−0.9[6]
Details
Mass1.4[6] M
Luminosity781[7] L
Temperature3,565[7] K
Other designations
AV Arietis, BD+18°277, FK5 1056, HD 13325, HIP 10155, HR 631, SAO 92822
Database references

15 Arietis (abbreviated 15 Ari) is a single[8] variable star in the northern constellation of Aries. 15 Arietis is the Flamsteed designation; it also bears the variable star designation AV Arietis. It has an apparent visual magnitude of 5.74,[8] which is just bright enough to be visible to the naked eye from dark suburban skies. An annual parallax shift of 5.84 mas[1] corresponds to a physical distance of approximately 560 light-years (170 parsecs) from Earth. At that distance, the star's brightness is reduced by 0.33[5] in magnitude because of extinction from interstellar gas and dust.

This is a red giant star with a stellar classification of M3 III.[3] The measured angular diameter of this star is 3.67 ± 0.11 mas.[9] At the estimated distance of Delta Ophiuchi,[1] this yields a physical size of about 67 times the radius of the Sun.[10] The radius determined from the observed brightness and colour of the star is 87 R.[6]

15 Arietis is a short period semiregular variable with the designation AV Arietis. The period given in the General Catalogue of Variable Stars is 5.032 days.[2] Longterm photometry finds that the strongest pulsation period is 18.1 days with an amplitude of 0.028 magnitudes, while a second is 21.9 days and 0.030 in magnitude.[3]

## References

1. van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
2. ^ a b c Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
3. ^ a b c Tabur, V.; et al. (December 2009), "Long-term photometry and periods for 261 nearby pulsating M giants", Monthly Notices of the Royal Astronomical Society, 400 (4): 1945–1961, arXiv:, Bibcode:2009MNRAS.400.1945T, doi:10.1111/j.1365-2966.2009.15588.x.
4. ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV data. Bibcode:1986EgUBV........0M.
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:, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272.
6. ^ a b c d Koen, Chris; Laney, Dave (2000). "Rapidly oscillating M giant stars?". Monthly Notices of the Royal Astronomical Society. 311 (3): 636. Bibcode:2000MNRAS.311..636K. doi:10.1046/j.1365-8711.2000.03127.x.
7. ^ a b McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427: 343. arXiv:. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x.
8. ^ 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:, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
9. ^ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.
10. ^ 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 {(170\cdot 3.67\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 134\cdot R_{\bigodot }\end{aligned}}}