Astronomy:FY Canis Majoris
Observation data Equinox J2000.0]] (ICRS) | |
---|---|
Constellation | Canis Major |
Right ascension | 07h 26m 59.48269s[1] |
Declination | −23° 05′ 09.6897″[1] |
Apparent magnitude (V) | 4.8 - 6.25[2] |
Characteristics | |
Spectral type | B0.5 IVe[3] |
Variable type | γ Cas[2] |
Astrometry | |
Proper motion (μ) | RA: −6.692±0.038[1] mas/yr Dec.: +4.054±0.078[1] mas/yr |
Parallax (π) | 1.7919 ± 0.0645[1] mas |
Distance | 1,820 ± 70 ly (560 ± 20 pc) |
Absolute magnitude (MV) | −2.23[4] |
Orbit[5] | |
Primary | Be star |
Companion | hot subdwarf |
Period (P) | 37.257±0.003 d |
Inclination (i) | >66[6]° |
Periastron epoch (T) | 2448529.64±0.15 |
Semi-amplitude (K1) (primary) | 14.4±0.9 km/s |
Semi-amplitude (K2) (secondary) | 128.2±2.2 km/s |
Details | |
Be star | |
Mass | 10-13[6] M☉ |
Radius | 6.8[6] R☉ |
Luminosity | 26,915[6] L☉ |
Temperature | 27,500±3,000[5] K |
Rotational velocity (v sin i) | 340±40[5] km/s |
hot subdwarf | |
Mass | 1.1-1.5[6] M☉ |
Radius | 0.81[6] R☉ |
Luminosity | 2,399[6] L☉ |
Temperature | 45,000±5,000[5] K |
Rotational velocity (v sin i) | 41±5[5] km/s |
Other designations | |
Database references | |
SIMBAD | data |
FY Canis Majoris (FY CMa), also known as HD 58978, is a star about 1,800 light years from the Earth, in the constellation Canis Major (very near the border of Puppis). It is usually a 5th magnitude star, so it will be visible to the naked eye of an observer far from city lights. It is a Gamma Cassiopeiae variable star, whose brightness varies from magnitude 4.8 to 6.25.
![](https://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/FYCMaLightCurve.png/250px-FYCMaLightCurve.png)
In 1967, Alejandro Feinstein detected low amplitude (0.14 magnitude) variability in HD 58978's brightness, from photoelectric observations at La Plata Observatory.[10] The star was given the variable star designation FY Canis Majoris in 1973.[11] During an outburst in 2009, the star brightened to magnitude 4.8, its historical peak brightness.[2] TESS data show that FY CMa pulsates at many different frequencies, with periods ranging from 1.07 hours to 5.8 days.[12]
In 1905, Edward King noted that FY CMa has a peculiar spectrum with an unusually bright Hβ (and other) emission lines.[13] Paul Merrill et al. listed it as a Be star in 1925.[14] Spectra taken by various observers over several decades of the 20th century showed that the strength and relative intensities of the star's emission line are variable,[3] and could change on a timescale of just a few days.[15]
In 2008, Geraldine Peters et al. obtained high resolution spectra from the IUE and found that the Be star has hot, far less massive subdwarf companion star, with which it forms a spectroscopic binary.[5]
Hui-Lau Cao calculated that FY CMa is losing mass at a rate of about 6 × 10−8 M☉/year via a stellar wind with a terminal velocity of about 750 km/sec.[16]
References
- ↑ Jump up to: 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ Jump up to: 2.0 2.1 2.2 "FY CMa". AAVSO. https://www.aavso.org/vsx/index.php?view=detail.top&oid=5341.
- ↑ Jump up to: 3.0 3.1 Slettebak, A. (September 1982). "Spectral types and rotational velocities of the brighter Be stars and A-F type shell stars". Astrophysical Journal Supplement Series 50: 55–83. doi:10.1086/190820. Bibcode: 1982ApJS...50...55S.
- ↑ Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode: 2012AstL...38..331A.
- ↑ Jump up to: 5.0 5.1 5.2 5.3 5.4 5.5 Peters, Geraldine J.; Gies, Douglas R.; Grundstrom, Erika D.; McSwain, M. Virginia (October 2008). "Detection of a Hot Subdwarf Companion to the Be Star FY Canis Majoris". Astrophysical Journal 686 (2): 1280–1291. doi:10.1086/591145. Bibcode: 2008ApJ...686.1280P.
- ↑ Jump up to: 6.0 6.1 6.2 6.3 6.4 6.5 6.6 Nazé, Yaël; Rauw, Gregor; Smith, Myron A.; Motch, Christian (2022). "The X-ray emission of Be+stripped star binaries★". Monthly Notices of the Royal Astronomical Society 516 (3): 3366. doi:10.1093/mnras/stac2245. Bibcode: 2022MNRAS.516.3366N.
- ↑ "HD 58978 -- Be Star". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+58978+--+Be+Star.
- ↑ "ASAS All Star Catalogue". The All Sky Automated Survey. http://www.astrouw.edu.pl/asas/?page=aasc.
- ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html.
- ↑ Feinstein, A. (1968). "A Survey of Southern Be Stars. II. Photometric data". Zeitschrift für Astrophysik 68: 29–47. Bibcode: 1968ZA.....68...29F.
- ↑ Kukarkin, B. V.; Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (October 1973). "59th Name-List of Variable Stars". Information Bulletin on Variable Stars 834 (1): 1. Bibcode: 1973IBVS..834....1K. https://ibvs.konkoly.hu/pub/ibvs/0801/0834.pdf. Retrieved 2 February 2023.
- ↑ Balona, L. A.; Ozuyar, D. (April 2020). "TESS observations of Be stars: a new interpretation". Monthly Notices of the Royal Astronomical Society 493 (2): 2528–2544. doi:10.1093/mnras/staa389. Bibcode: 2020MNRAS.493.2528B.
- ↑ Pickering, Edward C.; Fleming, W. P. (July 1905). "Stars having peculiar spectra. Spectra of known variables". Astrophysical Journal 22: 87–90. doi:10.1086/141242. Bibcode: 1905ApJ....22...87P.
- ↑ Merrill, P. W.; Humason, M. L.; Burwell, C. G. (June 1925). "Discovery and Observations of Stars of Class Be". Astrophysical Journal 61: 389–417. doi:10.1086/142899. Bibcode: 1925ApJ....61..389M.
- ↑ Peters, G. J. (May 1987). "FY Canis Majoris". IAU Circ. 4391: 2. Bibcode: 1987IAUC.4391....2P. http://www.cbat.eps.harvard.edu/iauc/04300/04391.html#Item0. Retrieved 1 February 2023.
- ↑ Cao, Hui-Lai (December 2001). "Infall and Outflow Activities in the Be star FY CMa". Chinese Journal of Astronomy & Astrophysics 1 (6): 514–524. doi:10.1088/1009-9271/1/6/514. Bibcode: 2001ChJAA...1..514C.
![]() | Original source: https://en.wikipedia.org/wiki/FY Canis Majoris.
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