TZ Arietis

TZ Arietis (also known as Gliese 83.1, GJ 9066, or L 1159-16) is a red dwarf in the northern constellation of Aries. With a normal apparent visual magnitude of 12.3, it is too faint to be seen by the naked eye, although it lies relatively close to the Sun at a distance of 14.6 light-years (4.47 parsecs). It is a flare star, which means it can suddenly increase in brightness for short periods of time.

TZ Arietis
TZ Arietis is located in the constellation Aries.
TZ Arietis is located in the constellation Aries.
TZ Arietis
Location of TZ Arietis in the constellation Aries

Observation data
Epoch J2000      Equinox J2000
Constellation Aries
Right ascension 02h 00m 12.95632s[1]
Declination +13° 03′ 07.0006″[1]
Apparent magnitude (V) 12.298[2]
Characteristics
Spectral type M4.5 V[3]
U−B color index +1.37[4]
B−V color index +1.80[4]
R−I color index 1.39[3]
Variable type Flare star
Astrometry
Radial velocity (Rv)−28.29±0.25[1] km/s
Proper motion (μ) RA: 1096.458 mas/yr[1]
Dec.: -1771.526 mas/yr[1]
Parallax (π)223.7321 ± 0.0699 mas[1]
Distance14.578 ± 0.005 ly
(4.470 ± 0.001 pc)
Absolute magnitude (MV)14.03[5]
Details
Mass0.14[6] M☉
Radius0.161[7] R☉
Luminosity0.00135[8] L☉
Surface gravity (log g)5.05[6] cgs
Temperature3,158[7] K
Metallicity [Fe/H]−0.14[7] dex
Rotational velocity (v sin i)3.8[8] km/s
Age4.8[6] Gyr
Other designations
TZ Ari, GJ 83.1, GJ 9066, G 003-033, L 1159-16, LFT 171, LHS 11, PLX 412.02, 2MASS J02001278+1303112[9]
Database references
SIMBADdata

Variability

TZ Arietis is a variable star. It is a flare star, showing brief increases in brightness due to eruptions from its surface. In the ultraviolet, flares of over a magnitude have been observed. In addition it shows longterm variations in brightness which may be due to starspots and rotation, possibly classifying it as a BY Draconis variable.[10] It was given the variable star designation TZ Arietis in 1970.[11]

Planetary system

In a preprint submitted to arXiv in June 2019, three candidate planets were reported in orbit around this star (GJ 83.1) with orbital periods of 2, 240, and 770 days.[12] A paper published in August 2020 reported a confirmation of the 240-day and 770-day planets, designating them "b" and "c", respectively.[13]

In March 2022, astronomers using the Calar Alto Observatory in Spain, as part of the CARMENES survey project, reported an independent confirmation of the 770-day planet, which they designated "b". However, they found no evidence for the 240-day planet, and confidently defined the 2-day candidate as nothing more than a spurious chromatic effect of the star, linked to its rotation.[14] The NASA Exoplanet Archive still refers to the confirmed, 770-day planet as "c".[15]

The TZ Arietis planetary system[14]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b[note 1] ≥0.21±0.02 MJ 0.88±0.02 771.36+1.34
−1.23		 0.46±0.04 — —

See also

References
  1. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. Landolt, Arlo U. (July 1992), "UBVRI photometric standard stars in the magnitude range 11.5-16.0 around the celestial equator", Astronomical Journal, 104 (1): 340–371, 436–491, Bibcode:1992AJ....104..340L, doi:10.1086/116242.
  3. Riaz, Basmah; Gizis, John E.; Harvin, James (August 2006), "Identification of New M Dwarfs in the Solar Neighborhood", The Astronomical Journal, 132 (2): 866–872, arXiv:astro-ph/0606617, Bibcode:2006AJ....132..866R, doi:10.1086/505632, S2CID 6282011.
  4. Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N.
  5. Boro Saikia, S.; et al. (2018), "Chromospheric activity catalogue of 4454 cool stars. Questioning the active branch of stellar activity cycles", Astronomy and Astrophysics, 616: A108, arXiv:1803.11123, Bibcode:2018A&A...616A.108B, doi:10.1051/0004-6361/201629518, S2CID 118915212.
  6. Yee, Samuel W.; Petigura, Erik A.; von Braun, Kaspar (2017), "Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library", The Astrophysical Journal, 836 (1): 77, arXiv:1701.00922, Bibcode:2017ApJ...836...77Y, doi:10.3847/1538-4357/836/1/77, S2CID 6302522.
  7. Houdebine, Éric R.; Mullan, D. J.; Doyle, J. G.; de la Vieuville, Geoffroy; Butler, C. J.; Paletou, F. (2019), "The Mass–Activity Relationships in M and K Dwarfs. I. Stellar Parameters of Our Sample of M and K Dwarfs", The Astronomical Journal, 158 (2): 56, arXiv:1905.07921, Bibcode:2019AJ....158...56H, doi:10.3847/1538-3881/ab23fe, S2CID 159041104.
  8. McLean, M.; Berger, E.; Reiners, Ansgar (February 2012), "The Radio Activity-Rotation Relation of Ultracool Dwarfs", The Astrophysical Journal, 746 (1): 23, arXiv:1108.0415, Bibcode:2012ApJ...746...23M, doi:10.1088/0004-637X/746/1/23, S2CID 119159519.
  9. "TZ Ari -- Flare Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-08-18.
  10. Gershberg, R. E.; Katsova, M. M.; Lovkaya, M. N.; Terebizh, A. V.; Shakhovskaya, N. I. (1999), "Catalogue and bibliography of the UV Cet-type flare stars and related objects in the solar vicinity", Astronomy and Astrophysics Supplement Series, 139 (3): 555–558, Bibcode:1999A&AS..139..555G, doi:10.1051/aas:1999407.
  11. Kukarkin, B. V.; Kholopov, P. N.; Perova, N. B. (October 1970), "57th Name-List of Variable Stars", Information Bulletin on Variable Stars, 480 (1): 1, Bibcode:1970IBVS..480....1K.
  12. Barnes, J. R.; et al. (2019-06-11), Frequency of planets orbiting M dwarfs in the Solar neighbourhood, arXiv:1906.04644.
  13. Feng, Fabo; Shectman, Stephen A.; Clement, Matthew S.; Vogt, Steven S.; Tuomi, Mikko; Teske, Johanna K.; Burt, Jennifer; Crane, Jeffrey D.; Holden, Bradford; Wang, Sharon Xuesong; Thompson, Ian B.; Díaz, Matías R.; Butler, R. Paul (2020), "Search for Nearby Earth Analogs .III. Detection of 10 New Planets, 3 Planet Candidates, and Confirmation of 3 Planets around 11 Nearby M Dwarfs", The Astrophysical Journal Supplement Series, 250 (2): 29, arXiv:2008.07998, Bibcode:2020ApJS..250...29F, doi:10.3847/1538-4365/abb139, S2CID 221150644.
  14. Quirrenbach, A.; et al. (2022), "The CARMENES search for exoplanets around M dwarfs", Astronomy & Astrophysics, 663: A48, arXiv:2203.16504, Bibcode:2022A&A...663A..48Q, doi:10.1051/0004-6361/202142915, S2CID 247835988.
  15. "GJ 9066". NASA Exoplanet Archive. Retrieved 27 September 2022.

Notes
  1. Referred to as c by some sources.

Further reading
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