| Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 03h 59m 55.48381s [2] |
| Declination | −24° 00′ 58.3798″ [2] |
| Apparent magnitude (V) | 4.63 [3] |
| Characteristics | |
| Spectral type | B9.5V Si [4] |
| U−B color index | −0.40 [3] |
| B−V color index | −0.13 [3] |
| Variable type | α2 CVn [5] |
| Astrometry | |
| Radial velocity (Rv) | 25.5±0.5 [6] km/s |
| Proper motion (μ) |
RA: +12.12
[2]
mas/
yr Dec.: +16.48 [2] mas/ yr |
| Parallax (π) | 9.96 ± 0.22 mas [2] |
| Distance | 327 ± 7
ly (100 ± 2 pc) |
| Absolute magnitude (MV) | −0.44 [5] |
| Orbit [7] | |
| Period (P) | 5.95382 days |
| Eccentricity (e) | 0.129 |
| Periastron epoch (T) | 246991.65 JD |
|
Argument of periastron (ω) (secondary) | 183.2° |
|
Semi-amplitude (K1) (primary) | 40.0 km/s |
| Semi-amplitude (K2) (secondary) | 89.9 km/s |
| Details | |
| τ9 Eri A | |
| Mass | 3.6 [7] M☉ |
| Radius | 3.06 [7] R☉ |
| Luminosity | 209 [7] L☉ |
| Surface gravity (log g) | 4.11±0.11 [8] cgs |
| Temperature | 12,580 [7] K |
| Rotational velocity (v sin i) | 26.8 [7] km/s |
| Age | 140 [7] Myr |
| τ9 Eri B | |
| Mass | 1.6 [7] M☉ |
| Radius | 1.5 [7] R☉ |
| Luminosity | 6.3 [7] L☉ |
| Temperature | 7530 [7] K |
| Rotational velocity (v sin i) | 15 [7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Tau9 Eridani (τ9 Eri) is a binary star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 4.63. [3] The distance to this system can be estimated using the parallax method, which yields a value of roughly 327 light years. [3]
This is a double-lined spectroscopic binary system with an orbital period of 5.95382 days and an eccentricity of 0.12. [7] The primary component, τ9 Eri A, is a magnetic chemically peculiar star [10] with a stellar classification of B9.5V Si, [4] indicating that it is a B-type main sequence star that shows abundance anomalies in its silicon absorption lines. [4] It is an Alpha² Canum Venaticorum variable [5] with a rotational periodicity of 5.954 days. [11] The averaged strength of the stellar effective magnetic field is 240.6±91.0 G. [4]
The primary component Tau9 Eridani A has an estimated 326% [10] the mass of the Sun and 3.1 times the Sun's radius. [8] It shines with 166 [12] times the solar luminosity from an outer atmosphere at an effective temperature of 10,866 K. [12] The star is spinning with a projected rotational velocity of 30 km/s. [13] The secondary star, designated Tau9 Eridani B, is a late A-type or early F-type star with a mass of 1.6 solar masses and an effective temperature of 7530 K. [7]
- ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
- ^ a b c d e 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.
- ^ a b c d e Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode: 1986EgUBV........0M.
- ^ a b c d Bychkov, V. D.; et al. (April 2009), "Catalogue of averaged stellar effective magnetic fields - II. Re-discussion of chemically peculiar A and B stars", Monthly Notices of the Royal Astronomical Society, 394 (3): 1338–1350, Bibcode: 2009MNRAS.394.1338B, doi: 10.1111/j.1365-2966.2008.14227.x, S2CID 120268049.
- ^ a b c Dubath, P.; et al. (2011), "Random forest automated supervised classification of Hipparcos periodic variable stars", Monthly Notices of the Royal Astronomical Society, 414 (3): 2602–2617, arXiv: 1101.2406, Bibcode: 2011MNRAS.414.2602D, doi: 10.1111/j.1365-2966.2011.18575.x, S2CID 118560311.
- ^ De Bruijne, J. H. J.; Eilers, A.-C. (2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: A61, arXiv: 1208.3048, Bibcode: 2012A&A...546A..61D, doi: 10.1051/0004-6361/201219219, S2CID 59451347.
- ^ a b c d e f g h i j k l m n Woodcock, K. (2021), "τ9 Eri: a bright pulsating magnetic Bp star in a 5.95-d double-lined spectroscopic binary", Monthly Notices of the Royal Astronomical Society, 502 (4): 5200–5209, arXiv: 2101.11732, Bibcode: 2021MNRAS.502.5200W, doi: 10.1093/mnras/stab338
- ^ a b North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics, 334: 181–187, arXiv: astro-ph/9802286, Bibcode: 1998A&A...334..181N.
-
^
"tau09 Eri".
SIMBAD.
Centre de données astronomiques de Strasbourg. Retrieved 2016-10-13.
{{ cite web}}: CS1 maint: postscript ( link) - ^ a b Shulyak, D.; et al. (September 2014), "Interferometry of chemically peculiar stars: theoretical predictions versus modern observing facilities", Monthly Notices of the Royal Astronomical Society, 443 (2): 1629–1642, arXiv: 1406.6093, Bibcode: 2014MNRAS.443.1629S, doi: 10.1093/mnras/stu1259.
- ^ Bychkov, V. D.; et al. (February 2005), "A catalog of stellar magnetic rotational phase curves", Astronomy and Astrophysics, 430 (3): 1143–1154, Bibcode: 2005A&A...430.1143B, doi: 10.1051/0004-6361:20034563.
- ^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv: 1208.2037, Bibcode: 2012MNRAS.427..343M, doi: 10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
- ^ Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode: 2002ApJ...573..359A, doi: 10.1086/340590.
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| Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 03h 59m 55.48381s [2] |
| Declination | −24° 00′ 58.3798″ [2] |
| Apparent magnitude (V) | 4.63 [3] |
| Characteristics | |
| Spectral type | B9.5V Si [4] |
| U−B color index | −0.40 [3] |
| B−V color index | −0.13 [3] |
| Variable type | α2 CVn [5] |
| Astrometry | |
| Radial velocity (Rv) | 25.5±0.5 [6] km/s |
| Proper motion (μ) |
RA: +12.12
[2]
mas/
yr Dec.: +16.48 [2] mas/ yr |
| Parallax (π) | 9.96 ± 0.22 mas [2] |
| Distance | 327 ± 7
ly (100 ± 2 pc) |
| Absolute magnitude (MV) | −0.44 [5] |
| Orbit [7] | |
| Period (P) | 5.95382 days |
| Eccentricity (e) | 0.129 |
| Periastron epoch (T) | 246991.65 JD |
|
Argument of periastron (ω) (secondary) | 183.2° |
|
Semi-amplitude (K1) (primary) | 40.0 km/s |
| Semi-amplitude (K2) (secondary) | 89.9 km/s |
| Details | |
| τ9 Eri A | |
| Mass | 3.6 [7] M☉ |
| Radius | 3.06 [7] R☉ |
| Luminosity | 209 [7] L☉ |
| Surface gravity (log g) | 4.11±0.11 [8] cgs |
| Temperature | 12,580 [7] K |
| Rotational velocity (v sin i) | 26.8 [7] km/s |
| Age | 140 [7] Myr |
| τ9 Eri B | |
| Mass | 1.6 [7] M☉ |
| Radius | 1.5 [7] R☉ |
| Luminosity | 6.3 [7] L☉ |
| Temperature | 7530 [7] K |
| Rotational velocity (v sin i) | 15 [7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Tau9 Eridani (τ9 Eri) is a binary star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 4.63. [3] The distance to this system can be estimated using the parallax method, which yields a value of roughly 327 light years. [3]
This is a double-lined spectroscopic binary system with an orbital period of 5.95382 days and an eccentricity of 0.12. [7] The primary component, τ9 Eri A, is a magnetic chemically peculiar star [10] with a stellar classification of B9.5V Si, [4] indicating that it is a B-type main sequence star that shows abundance anomalies in its silicon absorption lines. [4] It is an Alpha² Canum Venaticorum variable [5] with a rotational periodicity of 5.954 days. [11] The averaged strength of the stellar effective magnetic field is 240.6±91.0 G. [4]
The primary component Tau9 Eridani A has an estimated 326% [10] the mass of the Sun and 3.1 times the Sun's radius. [8] It shines with 166 [12] times the solar luminosity from an outer atmosphere at an effective temperature of 10,866 K. [12] The star is spinning with a projected rotational velocity of 30 km/s. [13] The secondary star, designated Tau9 Eridani B, is a late A-type or early F-type star with a mass of 1.6 solar masses and an effective temperature of 7530 K. [7]
- ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
- ^ a b c d e 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.
- ^ a b c d e Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode: 1986EgUBV........0M.
- ^ a b c d Bychkov, V. D.; et al. (April 2009), "Catalogue of averaged stellar effective magnetic fields - II. Re-discussion of chemically peculiar A and B stars", Monthly Notices of the Royal Astronomical Society, 394 (3): 1338–1350, Bibcode: 2009MNRAS.394.1338B, doi: 10.1111/j.1365-2966.2008.14227.x, S2CID 120268049.
- ^ a b c Dubath, P.; et al. (2011), "Random forest automated supervised classification of Hipparcos periodic variable stars", Monthly Notices of the Royal Astronomical Society, 414 (3): 2602–2617, arXiv: 1101.2406, Bibcode: 2011MNRAS.414.2602D, doi: 10.1111/j.1365-2966.2011.18575.x, S2CID 118560311.
- ^ De Bruijne, J. H. J.; Eilers, A.-C. (2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: A61, arXiv: 1208.3048, Bibcode: 2012A&A...546A..61D, doi: 10.1051/0004-6361/201219219, S2CID 59451347.
- ^ a b c d e f g h i j k l m n Woodcock, K. (2021), "τ9 Eri: a bright pulsating magnetic Bp star in a 5.95-d double-lined spectroscopic binary", Monthly Notices of the Royal Astronomical Society, 502 (4): 5200–5209, arXiv: 2101.11732, Bibcode: 2021MNRAS.502.5200W, doi: 10.1093/mnras/stab338
- ^ a b North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics, 334: 181–187, arXiv: astro-ph/9802286, Bibcode: 1998A&A...334..181N.
-
^
"tau09 Eri".
SIMBAD.
Centre de données astronomiques de Strasbourg. Retrieved 2016-10-13.
{{ cite web}}: CS1 maint: postscript ( link) - ^ a b Shulyak, D.; et al. (September 2014), "Interferometry of chemically peculiar stars: theoretical predictions versus modern observing facilities", Monthly Notices of the Royal Astronomical Society, 443 (2): 1629–1642, arXiv: 1406.6093, Bibcode: 2014MNRAS.443.1629S, doi: 10.1093/mnras/stu1259.
- ^ Bychkov, V. D.; et al. (February 2005), "A catalog of stellar magnetic rotational phase curves", Astronomy and Astrophysics, 430 (3): 1143–1154, Bibcode: 2005A&A...430.1143B, doi: 10.1051/0004-6361:20034563.
- ^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv: 1208.2037, Bibcode: 2012MNRAS.427..343M, doi: 10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
- ^ Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode: 2002ApJ...573..359A, doi: 10.1086/340590.
| Stars |
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| |||||||||||||
| Nebulae |
| ||||||||||||
| Galaxies |
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| |||||||||||||
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