HD 3346

HD 3346, also known as V428 Andromedae, is a binary star[11] system in the northern constellation of Andromeda. It is a dim star but visible to the naked eye under suitable viewing conditions, having an apparent visual magnitude of 5.14.[4] The distance to HD 3346 can be determined from its annual parallax shift of 4.95 mas.[1] This yields a range of about 660 light year. At that distance the brightness of the system is diminished by an extinction of 0.16 magnitude due to interstellar dust.[5] It is moving closer to the Earth with a heliocentric radial velocity of −33 km/s.[5]

HD 3167
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension  00h 36m 46.4403s[1]
Declination +44° 29′ 18.9169″[1]
Apparent magnitude (V) 5.13 – 5.19[2]
Characteristics
Spectral type K6 IIIa[3] (K5 - M0 III[2])
B−V color index 1.587±0.005[4]
Variable type SRS[2]
Astrometry
Radial velocity (Rv)−33.18±0.30[5] km/s
Proper motion (μ) RA: −36.578[1] mas/yr
Dec.: +32.491[1] mas/yr
Parallax (π)4.9507 ± 0.1896[1] mas
Distance660 ± 30 ly
(202 ± 8 pc)
Absolute magnitude (MV)−1.23[4]
Orbit[6]
Period (P)576.2±3.5 d
Eccentricity (e)0.30±0.06
Periastron epoch (T)43787±22 MJD
Argument of periastron (ω)
(secondary)		279±15°
Semi-amplitude (K1)
(primary)		0.69±0.08 km/s
Details
Radius48[7] R☉
Luminosity817.99[8] or 1001.25[4] L☉
Surface gravity (log g)1.19±0.16[9] cgs
Temperature3909±170[9] K
Metallicity [Fe/H]−0.00±0.10[9] dex
Other designations
V428 Andromedae, BD+43°113, HD 3346, HIP 2900, HR 152, SAO 36509[10]
Database references
SIMBADdata

Binary system

This is a single-lined spectroscopic binary system with an orbital period of 576 days and an eccentricity of 0.3. The a sin i value for the primary is 5.1 ± 0.6 Gm (0.0341 ± 0.0040 AU), where a is the semimajor axis and i is the (unknown) orbital inclination. The provides a minimum value for the actual semimajor axis.[6]

The visible component is a red giant star and has been defined as a standard star for the stellar classification of K6 IIIa.[3] Prior to that there had been no spectral standard for K6 giants and HD 3346 had been classified between K5 III and M0 III.[12]

Variability

V428 Andromedae is the variable star designation for HD 3346. It is a short-period semi-regular variable (type SRS),[2] also called an ultra-small-amplitude pulsating red giant.[13] It has an amplitude of only 0.065 magnitudes.[13] The main pulsation period is 11.5 days, but other periods of 11, 15, and 22 days have been detected.[14][13]

Possible planetary system

In 1996 it was announced that the variations in radial velocity of this star were larger than expected. A planetary system was proposed to explain this variation.[15][16]

The HD 3346 planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b (unconfirmed) 10 MJ 0.3 30.0 0 — —
c (unconfirmed) 60 MJ 2.5 650 0.00 — —

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.
  2. N. N. Samus; O. V. Durlevich; et al. "V428 And database entry". Combined General Catalog of Variable Stars (2017 ed.). CDS. Retrieved 2018-11-12.
  3. Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
  4. 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.
  5. 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. McClure, R. D.; et al. (August 1985), "A spectroscopic orbit for HR 152", Publications of the Astronomical Society of the Pacific, 97: 740–744, Bibcode:1985PASP...97..740M, doi:10.1086/131600
  7. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451
  8. McDonald, I.; et al. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x.
  9. Röck, B.; Vazdekis, A.; Peletier, R. F.; Knapen, J. H.; Falcón-Barroso, J. (2015). "Stellar population synthesis models between 2.5 and 5 μm based on the empirical IRTF stellar library". Monthly Notices of the Royal Astronomical Society. 449 (3): 2853. Bibcode:2015MNRAS.449.2853R. doi:10.1093/mnras/stv503.
  10. "HD 3167". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 6, 2018.
  11. Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x.
  12. Keenan, P. C.; Pitts, R. E. (1980). "Revised MK spectral types for G, K ANS M stars". The Astrophysical Journal Supplement Series. 42: 541. Bibcode:1980ApJS...42..541K. doi:10.1086/190662.
  13. Percy, John R.; et al. (December 2001), "Periods of Eleven K5-M0 Pulsating Red Giants", Information Bulletin on Variable Stars, 5209: 1, Bibcode:2001IBVS.5209....1P
  14. Glass, I. S.; Van Leeuwen, F. (2007). "Semiregular variables in the solar neighbourhood". Monthly Notices of the Royal Astronomical Society. 378 (4): 1543–1549. arXiv:0704.3150. Bibcode:2007MNRAS.378.1543G. doi:10.1111/j.1365-2966.2007.11903.x.
  15. Noyes, R.; et al. (1996). "HD 3346". IAU Circular (6316): 1.
  16. Bell, George H. (2001-04-05). "The Search for the Extrasolar Planets: A Brief History of the Search, the Findings and the Future Implications". Arizona State University. Retrieved 2008-07-16.
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