Nu Phoenicis

Nu Phoenicis is a F-type main-sequence star in the southern constellation of Phoenix. It is visible to the naked eye with an apparent visual magnitude of 4.95.[2] This is a solar analogue, meaning its observed properties appear similar to the Sun, although it is somewhat more massive. At an estimated distance of around 49.5 light years,[4] this star is located relatively near the Sun.

Nu Phoenicis
Location of ν Phoenicis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Phoenix
Right ascension  01h 15m 11.12150s[1]
Declination –45° 31′ 53.9954″[1]
Apparent magnitude (V) 4.95[2]
Characteristics
Spectral type F9 V Fe+0.4[3]
U−B color index +0.09[2]
B−V color index +0.57[2]
Astrometry
Radial velocity (Rv)+11.82 ± 0.15[4] km/s
Proper motion (μ) RA: 664.28[4] mas/yr
Dec.: 179.06[4] mas/yr
Parallax (π)65.8894 ± 0.1803[4] mas
Distance49.5 ± 0.1 ly
(15.18 ± 0.04 pc)
Absolute magnitude (MV)4.07[5]
Details[5]
Mass1.17 M☉
Radius1.26 ± 0.04 R☉
Luminosity2.0 ± 0.1 L☉
Surface gravity (log g)4.31 ± 0.10 cgs
Temperature6,066 ± 70 K
Metallicity [Fe/H]+0.16 ± 0.06 dex
Rotational velocity (v sin i)3.7 ± 0.5 km/s
Age4.2[6] Gyr
Other designations
CD–46° 346, GCTP 257.00, Gl 55, HD 7570, HIP 5862, HR 370, LHS 1220, LTT 696, SAO 215428.[7]
Database references
SIMBADdata

Based on observations of excess infrared radiation from this star, it may possess a dust ring that extends outward several AU from an inner edge starting at 10 AU.[8]

Properties

This is an F-type main-sequence star with a spectral type of F9V Fe+0.4,[3] indicating it is similar to the Sun but somewhat hotter and more luminous. The notation 'Fe+0.4' indicates strong iron absorption lines; the star is indeed metal-rich, with an iron abundance 45% greater than the Sun's. Nu Phoenicis has an estimated mass of 1.17 times the solar mass and a radius of 1.26 times the solar radius. It is shining with about double the solar luminosity at an effective temperature of 6,070 K.[5]

Activity and age

Nu Phoenicis has a projected rotational velocity of 3.7 km/s,[5] and a low chromospheric activity index (log R′HK = −4.95).[9] These values indicate that the star is not particularly young and has an age of a few billion years; empirical calibrations estimate from the rotational velocity an age of 2.4 billion years, and from the activity index an age of 5.67 billion years.[9] Similarly, stellar evolution models estimate an age between 1 and 6 billion years, with a more probable value of 4.2 billion years.[6]

Companions

Nu Phoenicis has no known companions, and is considered to be a single star.[5] As a bright star similar to the Sun, it has been targeted in a number of studies searching for planets with the radial velocity method, but no detection has been made. High-precision observations with the HARPS spectrograph show that the radial velocity of the star has no significant variability, and is constant to 2.67 m/s, a value similar to the estimated jitter level of 2.48 m/s.[10] The star has also been included in the observations of the Anglo-Australian Planet Search, which did not find Jupiter-analogs with periods up to 6,000 days.[11]

Debris disk

Nu Phoenicis emits a significant amount of infrared excess, in comparison to the expected emission from the star's photosphere, indicating it has a circunstellar debris disk that is warmed by the star and emits thermal radiation.[8] The excess has been detected in long wavelenghts, between 30[8] and 100 μm[12], indicating relatively cold dust many astronomical units away from the star. Modeling the emission as a black body, the disk has an estimated temperature of 96 K and a radius of 12 AU, contributing to 0.00024% of the system's luminosity.[12]

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See also

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. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD: 0, Bibcode:1986EgUBV........0M.
  3. Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637.
  4. 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.
  5. Fuhrmann, K.; Chini, R.; Kaderhandt, L.; Chen, Z. (2017). "Multiplicity among Solar-type Stars". The Astrophysical Journal. 836 (1): 139. Bibcode:2017ApJ...836..139F. doi:10.3847/1538-4357/836/1/139.
  6. Casagrande, L.; et al. (June 2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy and Astrophysics, 530: A138, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276.
  7. "nu. Phe -- High proper-motion Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2015-12-22.
  8. Beichman, C. A.; Tanner, A.; Bryden, G.; Stapelfeldt, K. R.; et al. (2006). "IRS Spectra of Solar-Type Stars: A Search for Asteroid Belt Analogs". Astrophysical Journal. 639 (2): 1166–1176. arXiv:astro-ph/0601467. Bibcode:2006ApJ...639.1166B. doi:10.1086/499424.
  9. Vican, Laura (June 2012), "Age Determination for 346 Nearby Stars in the Herschel DEBRIS Survey", The Astronomical Journal, 143 (6): 135, arXiv:1203.1966, Bibcode:2012AJ....143..135V, doi:10.1088/0004-6256/143/6/135.
  10. Zechmeister, M.; et al. (2013). "The planet search programme at the ESO CES and HARPS. IV. The search for Jupiter analogues around solar-like stars". Astronomy & Astrophysics. 592: A78. arXiv:1211.7263. Bibcode:2013A&A...552A..78Z. doi:10.1051/0004-6361/201116551.
  11. Wittenmyer, Robert A.; Butler, R. P.; Tinney, C. G.; Horner, Jonathan; Carter, B. D.; Wright, D. J.; Jones, H. R. A.; Bailey, J.; O'Toole, Simon J. (2016). "The Anglo-Australian Planet Search XXIV: The Frequency of Jupiter Analogs". The Astrophysical Journal. 819 (1): 28. arXiv:1601.05465. Bibcode:2016ApJ...819...28W. doi:10.3847/0004-637x/819/1/28.
  12. Montesinos, B.; et al. (September 2016), "Incidence of debris discs around FGK stars in the solar neighbourhood", Astronomy & Astrophysics, 593: 31, arXiv:1605.05837, Bibcode:2016A&A...593A..51M, doi:10.1051/0004-6361/201628329, A51.
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