HD 16955
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Aries |
| Right ascension | 02h 43m 51.24421s |
| Declination | +25° 38′ 18.0493″ |
| Apparent magnitude (V) | 6.376 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | A3 V |
| B−V color index | 0.089±0.002 |
| Astrometry | |
| Radial velocity (Rv) | −10.3±3.1 km/s |
| Proper motion (μ) | RA: −4.98±0.70 mas/yr Dec.: +6.04±0.52 mas/yr |
| Parallax (π) | 9.59±0.76 mas |
| Distance | 340 ± 30 ly (104 ± 8 pc) |
| Absolute magnitude (MV) | +1.18±0.13 |
| Details | |
| HD 16955 A | |
| Mass | 2.25±0.08 M☉ |
| Radius | 2.4 R☉ |
| Luminosity | 26.9+3.3 −2.9 L☉ |
| Surface gravity (log g) | 3.97 cgs |
| Temperature | 8,450±164 K |
| Rotational velocity (v sin i) | 175 km/s |
| Age | 1.6 Gyr |
| Other designations | |
| BD+25°441, HD 16955, HIP 12744, HR 803, SAO 75539 | |
| Database references | |
| SIMBAD | data |
HD 16955, also known as HR 803, is a double or multiple star. With an apparent visual magnitude of 6.376, is lies at or below the nominal limit for visibility with a typical naked eye. The measured annual parallax shift is 9.59 milliarcseconds, which yields an estimated distance of around 340 light years. The star is moving closer to the Sun with a heliocentric radial velocity of around -10 km/s.
This is an A-type main-sequence star with a stellar classification of A3 V. Hauck et al. (1995) identified this as a Lambda Boötis star with a circumstellar shell, but this now appears to be unlikely. It has 2.25 times the mass of the Sun and is spinning rapidly with a projected rotational velocity of 175 km/s. The star is radiating about 27 times the Sun's luminosity from its photosphere at an effective temperature of roughly 8,450 K.
HD 16955 has a magnitude 10.36 companion, component B, which is located, as of 2015, at an angular separation of 3.0 arcseconds along a position angle of 19°. This is the likely source for the detected X-ray emission with a luminosity of 262.5×1020 W coming from these coordinates, since A-type stars are not expected to emit X-rays. Component C is a more distant magnitude 12.94 companion located at a separation of 51.10 arcseconds along a position angle of 92°, as of 2015.
References
- 1 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. XHIP record for this object at VizieR.
- 1 2 3 4 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. S2CID 18759600.
- 1 2 3 4 5 6 7 8 Murphy, Simon J.; Paunzen, Ernst (April 2017). "Gaia's view of the λ Boo star puzzle". Monthly Notices of the Royal Astronomical Society. 466 (1): 546−555. arXiv:1612.01528. Bibcode:2017MNRAS.466..546M. doi:10.1093/mnras/stw3141. S2CID 119328659.
- ↑ Lambert, David L.; Reddy, Bacham E. (2004). "Lithium abundances of the local thin disc stars". Monthly Notices of the Royal Astronomical Society. 349 (2): 757–767. arXiv:astro-ph/0401259. Bibcode:2004MNRAS.349..757L. doi:10.1111/j.1365-2966.2004.07557.x. S2CID 118931004.
- 1 2 Cowley, A.; et al. (April 1969). "A study of the bright A stars. I. A catalogue of spectral classifications". Astronomical Journal. 74: 375–406. Bibcode:1969AJ.....74..375C. doi:10.1086/110819.
- 1 2 Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
- 1 2 Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy & Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. S2CID 55586789.
- ↑ Schofield, Mathew; et al. (2019). "The Asteroseismic Target List for Solar-like Oscillators Observed in 2 minute Cadence with the Transiting Exoplanet Survey Satellite". The Astrophysical Journal Supplement Series. 241 (1): 12. arXiv:1901.10148. Bibcode:2019ApJS..241...12S. doi:10.3847/1538-4365/ab04f5.
- 1 2 Aguilera-Gómez, Claudia; et al. (2018). "Lithium abundance patterns of late-F stars: An in-depth analysis of the lithium desert". Astronomy and Astrophysics. 614: A55. arXiv:1803.05922. Bibcode:2018A&A...614A..55A. doi:10.1051/0004-6361/201732209. S2CID 62799777.
- 1 2 Royer, F.; et al. (February 2007). "Rotational velocities of A-type stars. III. Velocity distributions". Astronomy and Astrophysics. 463 (2): 671–682. arXiv:astro-ph/0610785. Bibcode:2007A&A...463..671R. doi:10.1051/0004-6361:20065224. S2CID 18475298.
- ↑ "HD 16955". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-02-26.
- ↑ Hauck, B.; et al. (March 1995). "Three other λ Bootis stars with a shell". Astronomy and Astrophysics Supplement. 109: 505−510. Bibcode:1995A&AS..109..505H.
- 1 2 Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
- ↑ 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.
