C Hydrae

C Hydrae
	Location of C Hydrae (circled)
Observation data; Epoch J2000 Equinox J2000
Constellation	Hydra
Right ascension	08h 25m 39.63201s
Declination	−03° 54′ 23.1178″
Apparent magnitude (V)	3.90
Characteristics
Spectral type	A0 Va
B−V color index	−0.012±0.003
Astrometry
Radial velocity (Rv)	+10.00±1.78 km/s
Proper motion (μ)	RA: −66.43 mas/yr ; Dec.: −23.41 mas/yr
Parallax (π)	26.66±0.19 mas
Distance	122.3 ± 0.9 ly ; (37.5 ± 0.3 pc)
Absolute magnitude (MV)	1.04
Details
Mass	2.3 M☉
Radius	2.5 R☉
Luminosity	37 L☉
Surface gravity (log g)	4.20 cgs
Temperature	9,074 K
Metallicity [Fe/H]	−0.04 dex
Rotational velocity (v sin i)	129 km/s
Age	162 Myr
Other designations
	C Hya, 30 Mon, BD−03°2339, HD 71155, HIP 41307, HR 3314, SAO 135896
Database references
SIMBAD	data

C Hydrae is a single^[10] star in the equatorial constellation of Hydra,^[9] located 122 light years away from the Sun.^[2] It has the Flamsteed designation 30 Monocerotis,^[9] assigned when it belonged to the constellation Monoceros. The object is visible to the naked eye as a white-hued star with an apparent visual magnitude of 3.90.^[3] It is moving away from the Earth with a heliocentric radial velocity of +10 km/s.^[5]

This is an A-type main-sequence star with a stellar classification of A0 Va.^[4] It is around 162^[7] million years old with a high rate of spin, showing a projected rotational velocity of 129 km/s. The star has 2.3 times the mass of the Sun and about 2.5 times the Sun's radius. It is radiating 37 times the luminosity of the Sun from its photosphere at an effective temperature of 9,074 K.

A statistically significant infrared excess has been detected, indicating a debris disk is orbiting 2.0±0.1 AU from the host star with a blackbody temperature of 499±3 K. It is comparable in size to the asteroid belt.^[11] Unexplained X-ray emission has also been detected coming from these coordinates – stars of this class are not normally expected to show X-ray emission, so it may be coming from a background source or an unseen companion.^[12]

References

^ ^a ^b ^c 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.
^ ^a ^b ^c ^d ^e ^f 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 Baines, Ellyn K.; et al. (2018), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal, 155 (1), 30, arXiv:1712.08109, Bibcode:2018AJ....155...30B, doi:10.3847/1538-3881/aa9d8b, S2CID 119427037.
^ ^a ^b 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, S2CID 119476992.
^ ^a ^b de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
^ ^a ^b ^c ^d Hardegree-Ullman, Kevin K.; Apai, Dániel; Bergsten, Galen J.; Pascucci, Ilaria; López-Morales, Mercedes (2023), "Bioverse: A Comprehensive Assessment of the Capabilities of Extremely Large Telescopes to Probe Earth-like O₂ Levels in Nearby Transiting Habitable-zone Exoplanets", The Astronomical Journal, 165 (6): 267, arXiv:2304.12490, Bibcode:2023AJ....165..267H, doi:10.3847/1538-3881/acd1ec.
^ ^a ^b ^c ^d 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, S2CID 33401607.
^ Gáspár, András; Rieke, George H.; Ballering, Nicholas (2016), "The Correlation between Metallicity and Debris Disk Mass", The Astrophysical Journal, 826 (2): 171, arXiv:1604.07403, Bibcode:2016ApJ...826..171G, doi:10.3847/0004-637X/826/2/171.
^ ^a ^b ^c "30 Mon", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved May 7, 2019.
^ 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, S2CID 14878976.
^ Moerchen, Margaret M.; et al. (November 2010), "High Spatial Resolution Imaging of Thermal Emission from Debris Disks", The Astrophysical Journal, 723 (2): 1418–1435, arXiv:1011.1410, Bibcode:2010ApJ...723.1418M, doi:10.1088/0004-637X/723/2/1418, S2CID 118648798.
^ 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.

[Anderson2012-1] 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.

[vanLeeuwen2007-2] ^ ^a ^b ^c ^d ^e ^f 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.

[Baines2018-3] Baines, Ellyn K.; et al. (2018), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal, 155 (1), 30, arXiv:1712.08109, Bibcode:2018AJ....155...30B, doi:10.3847/1538-3881/aa9d8b, S2CID 119427037.

[Gray2006-4] 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, S2CID 119476992.

[deBruijne2012-5] Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.

[hu2023-6] Hardegree-Ullman, Kevin K.; Apai, Dániel; Bergsten, Galen J.; Pascucci, Ilaria; López-Morales, Mercedes (2023), "Bioverse: A Comprehensive Assessment of the Capabilities of Extremely Large Telescopes to Probe Earth-like O₂ Levels in Nearby Transiting Habitable-zone Exoplanets", The Astronomical Journal, 165 (6): 267, arXiv:2304.12490, Bibcode:2023AJ....165..267H, doi:10.3847/1538-3881/acd1ec.

[David2015-7] 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, S2CID 33401607.

[gaspar2016-8] Gáspár, András; Rieke, George H.; Ballering, Nicholas (2016), "The Correlation between Metallicity and Debris Disk Mass", The Astrophysical Journal, 826 (2): 171, arXiv:1604.07403, Bibcode:2016ApJ...826..171G, doi:10.3847/0004-637X/826/2/171.

[SIMBAD-9] "30 Mon", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved May 7, 2019.

[Eggleton2008-10] 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, S2CID 14878976.

[Moerchen2010-11] Moerchen, Margaret M.; et al. (November 2010), "High Spatial Resolution Imaging of Thermal Emission from Debris Disks", The Astrophysical Journal, 723 (2): 1418–1435, arXiv:1011.1410, Bibcode:2010ApJ...723.1418M, doi:10.1088/0004-637X/723/2/1418, S2CID 118648798.

[Schroeder2007-12] 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.

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C Hydrae

References

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