HD 16754

HD 16754 is a binary[12] or triple-star[8] system in the constellation Eridanus. It has the Bayer designation s Eridani; HD 16754 is the designation from the Henry Draper catalogue. The system is visible to the naked eye as a faint point of light with an apparent visual magnitude of +4.74.[2] It is located at a distance of approximately 132 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +18 km/s.[2] The system is a member of the Columba association of co-moving stars.[13]

This article is about s Eridani. For S Eridani, see 64 Eridani.
HD 16754
Observation data
Epoch J2000      Equinox J2000
Constellation Eridanus
Right ascension  02h 39m 47.96544s[1]
Declination −42° 53′ 30.3638″[1]
Apparent magnitude (V) +4.74[2]
Characteristics
Spectral type A1 Vb[3] + M2-5V[4] + ?
B−V color index 0.061±0.003[2]
Astrometry
Radial velocity (Rv)+18.0±4.2[2] km/s
Proper motion (μ) RA: +88.20[5] mas/yr
Dec.: −17.82[5] mas/yr
Parallax (π)24.7076 ± 0.3930[1] mas
Distance132 ± 2 ly
(40.5 ± 0.6 pc)
Absolute magnitude (MV)+1.76[6]
Details
Aa
Mass1.95[7] M☉
Radius1.93[8] R☉
Luminosity17.44[2] L☉
Surface gravity (log g)4.40±0.14[7] cgs
Temperature9,099±309[7] K
Metallicity [Fe/H]−0.06[3] dex
Rotational velocity (v sin i)167.6±1.7[9] or 13.4±1.5[10] km/s
Age212[7] or 30[8] Gyr
Other designations
s Eri, CD−43°814, FK5 2185, HD 16754, HIP 12413, HR 789, SAO 215996[11]
Database references
SIMBADdata

This object was flagged as an astrometric binary based on proper motion measurements made from the Hipparcos spacecraft.[14][15] Zuckerman et al. (2011) consider it a multi-star system, with a bright A-type primary plus a faint M-type companion at an angular separation of 25″ to the north. The astrometric companion to the primary remains unresolved.[8]

The main component is an A-type main-sequence star with a stellar classification of A1 Vb.[3] Based upon stellar models, it has an age estimated at 212 million years.[7] Consistency with its membership in the Columba association suggests a much younger age of 30 million years.[8] Earlier measurements showed a high projected rotational velocity of 168 km/s.[9] However, Ammler-von Eiff and Reiners (2012) found a much lower velocity of 13 km/s.[10]

The visible companion is a red dwarf star with a class in the range M2-5V. The system is a source of X-ray emission with a luminosity of 924×1020 W, which is most likely coming from this component and the unresolved companion.[4]

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. Gaia DR2 record for this source at VizieR.
  2. 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.
  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. Schröder, C.; Schmitt, J. H. M. M. (November 2007), "X-ray emission from A-type stars", Astronomy and Astrophysics, 475 (2): 677–684, Bibcode:2007A&A...475..677S, doi:10.1051/0004-6361:20077429.
  5. van Leeuwen, F. (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.
  6. Ammler-von Eiff, M.; Reiners, A. (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: A116, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724.
  7. David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146.
  8. Zuckerman, B.; et al. (May 2011), "The Tucana/Horologium, Columba, AB Doradus, and Argus Associations: New Members and Dusty Debris Disks", The Astrophysical Journal, 732 (2): 61, arXiv:1104.0284v1, Bibcode:2011ApJ...732...61Z, doi:10.1088/0004-637X/732/2/61.
  9. Díaz, C. G.; et al. (July 2011), "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum", Astronomy & Astrophysics, 531: A143, arXiv:1012.4858, Bibcode:2011A&A...531A.143D, doi:10.1051/0004-6361/201016386.
  10. Ammler-von Eiff, M.; Reiners, A. (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: A116, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724.
  11. "HD 16754". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-12-16.
  12. 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.
  13. Elliott, P.; et al. (May 2016), "Search for associations containing young stars (SACY). VII. New stellar and substellar candidate members in the young associations", Astronomy & Astrophysics, 590: 28, arXiv:1604.03550, Bibcode:2016A&A...590A..13E, doi:10.1051/0004-6361/201628253, A13.
  14. Makarov, V. V.; Kaplan, G. H. (May 2005), "Statistical Constraints for Astrometric Binaries with Nonlinear Motion", The Astronomical Journal, 129 (5): 2420–2427, Bibcode:2005AJ....129.2420M, doi:10.1086/429590.
  15. Frankowski, A.; et al. (March 2007), "Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data", Astronomy and Astrophysics, 464 (1): 377–392, arXiv:astro-ph/0612449, Bibcode:2007A&A...464..377F, doi:10.1051/0004-6361:20065526.
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