Astronomy:HD 16754
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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 |
| Distance | 132 ± 2 ly (40.5 ± 0.6 pc) |
| Absolute magnitude (MV) | +1.76[6] |
| Details | |
| Aa | |
| Mass | 1.95[7] M☉ |
| Radius | 1.93[8] R☉ |
| Luminosity | 17.44[2] L☉ |
| Surface gravity (log g) | 4.40±0.14[7] cgs |
| Temperature | 9,099±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[6] km/s |
| Age | 212[7] or 30[8] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 16754 is a binary[11] 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.[12]
This object was flagged as an astrometric binary based on proper motion measurements made from the Hipparcos spacecraft.[13][14] 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.[6]
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
- ↑ 1.0 1.1 1.2 1.3 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 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, doi:10.1086/504637, Bibcode: 2006AJ....132..161G.
- ↑ 4.0 4.1 Schröder, C.; Schmitt, J. H. M. M. (November 2007), "X-ray emission from A-type stars", Astronomy and Astrophysics 475 (2): 677–684, doi:10.1051/0004-6361:20077429, Bibcode: 2007A&A...475..677S.
- ↑ 5.0 5.1 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 6.0 6.1 6.2 Ammler-von Eiff, Matthias; Reiners, Ansgar (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, doi:10.1051/0004-6361/201118724, Bibcode: 2012A&A...542A.116A.
- ↑ 7.0 7.1 7.2 7.3 7.4 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, doi:10.1088/0004-637X/804/2/146, Bibcode: 2015ApJ...804..146D.
- ↑ 8.0 8.1 8.2 8.3 8.4 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, doi:10.1088/0004-637X/732/2/61, Bibcode: 2011ApJ...732...61Z.
- ↑ 9.0 9.1 Díaz, C. G. et al. (July 2011), "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum", Astronomy & Astrophysics 531: A143, doi:10.1051/0004-6361/201016386, Bibcode: 2011A&A...531A.143D.
- ↑ "HD 16754". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+16754.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 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, doi:10.1051/0004-6361/201628253, A13, Bibcode: 2016A&A...590A..13E.
- ↑ Makarov, V. V.; Kaplan, G. H. (May 2005), "Statistical Constraints for Astrometric Binaries with Nonlinear Motion", The Astronomical Journal 129 (5): 2420–2427, doi:10.1086/429590, Bibcode: 2005AJ....129.2420M.
- ↑ 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, doi:10.1051/0004-6361:20065526, Bibcode: 2007A&A...464..377F.
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