AO Cassiopeiae

Last updated
AO Cas
Cassiopeia constellation map.svg
Red circle.svg
Location of AO Cas (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Cassiopeia
Right ascension 00h 17m 43.062s [1]
Declination +51° 25 59.12 [1]
Apparent magnitude  (V)6.14 [2] (6.07-6.24 [3] )
Characteristics
Spectral type O8V((f)) + O9.2II [4]
U−B color index 0.97 [2]
B−V color index 0.13 [2]
Variable type Eclipsing Variable star [3]
Astrometry
Radial velocity (Rv)−31.10 [5]  km/s
Proper motion (μ)RA: −3.98 ± 0.35 [1]   mas/yr
Dec.: −1.76 ± 0.29 [1]   mas/yr
Parallax (π)1.36 ± 0.44  mas [1]
Distance approx. 2,400  ly
(approx. 700  pc)
Absolute magnitude  (MV) [6]
Orbit [7]
Period (P)3.52348 days
Semi-major axis (a)28.57 R
Eccentricity (e)0
Inclination (i)65.7°
Longitude of the node (Ω)3.10°
Semi-amplitude (K1)
(primary)
143.7 km/s
Semi-amplitude (K2)
(secondary)
230.6 km/s
Details [7]
II
Mass 9.65  M
Radius 9.43  R
Luminosity 115,000 [8]   L
Surface gravity (log g)3.45  cgs
Temperature 29,239  K
Rotational velocity (v sin i)120 [8]  km/s
V
Mass 15.59  M
Radius 4.61  R
Luminosity66,000 [8]   L
Surface gravity (log g)4.30  cgs
Temperature 33,675  K
Rotational velocity (v sin i)130 [8]  km/s
Other designations
Pearce's Star, [9] AO  Cas, HR  65, BD+50°46, HD  1337, SAO  21273, HIP  1415
Database references
SIMBAD data

AO Cassiopeiae, also known as Pearce's Star, is a binary system composed of an O8 main sequence star and an O9.2 bright giant that respectively weigh anywhere between 20.30 and 57.75 times and 14.8 and 31.73 times the mass of the Sun. [10]

A light curve for AO Cassiopeiae, plotted from Hipparcos data AOCasLightCurve.png
A light curve for AO Cassiopeiae, plotted from Hipparcos data

The AO Cas system is an eclipsing binary with a period of roughly 3.5 days, with the apparent magnitude ranging between 6.07 and 6.24. [11] Stars of this brightness are generally just visible to the unaided eye in dark skies in semirural locations. [12] The component stars are so close to each other they are ellipsoidal (egg-shaped). [13] AO Cas is considered a contact binary, with both stars at or near their Roche lobes. [3]

Related Research Articles

<span class="mw-page-title-main">Eta Cassiopeiae</span> Binary star system in the constellation Cassiopeia

Eta Cassiopeiae is a binary star system in the northern constellation of Cassiopeia. Its binary nature was first discovered by William Herschel in August 1779. Based upon parallax measurements, the distance to this system is 19.42 light-years from the Sun. The two components are designated Eta Cassiopeiae A and B.

<span class="mw-page-title-main">26 Andromedae</span> Star in the constellation Andromeda

26 Andromedae, abbreviated 26 And, is a binary star system in the constellation Andromeda. 26 Andromedae is the Flamsteed designation. It has a combined apparent visual magnitude of 6.10, which is near the lower limit of visibility to the naked eye. The distance to this system can be estimated from its annual parallax shift of 5.35 mas, which yields a distance of about 600 light years. At that distance, the visual magnitude of the stars is diminished from an extinction of 0.04 due to interstellar dust. The system is moving further from the Earth with a heliocentric radial velocity of +3.3 km/s.

<span class="mw-page-title-main">9 Aurigae</span> Multiple star system in the constellation Auriga

9 Aurigae is a star system in Auriga (constellation). It has an apparent magnitude of about 5, making it visible to the naked eye in many suburban skies. Parallax estimates made by the Hipparcos spacecraft put it at about 86 light-years from the solar system, although individual Gaia Data Release 3 parallaxes place all three components at 88 light years.

<span class="mw-page-title-main">Kappa Boötis</span> Double star in the constellation of Boötes

Kappa Boötis is a double star in the constellation Boötes. It has the traditional name Asellus Tertius and the Flamsteed designation 17 Boötis. The components are separated by an angular distance of 13.5 arcsec, viewable in a small telescope. Kappa Boötis is approximately 155 light years from Earth.

<span class="mw-page-title-main">Gamma Cassiopeiae</span> Star in the constellation Cassiopeia

Gamma Cassiopeiae, Latinized from γ Cassiopeiae, is a bright star at the center of the distinctive "W" asterism in the northern circumpolar constellation of Cassiopeia. Although it is a fairly bright star with an apparent visual magnitude that varies from 1.6 to 3.0, it has no traditional Arabic or Latin name. It sometimes goes by the informal name Navi.

<span class="mw-page-title-main">Mu Cassiopeiae</span>

Mu Cassiopeiae, Latinized from μ Cassiopeiae, is a binary star system in the constellation Cassiopeia. This system shares the name Marfak with Theta Cassiopeiae, and the name was from Al Marfik or Al Mirfaq (المرفق), meaning "the elbow". It is dimly visible to the naked eye as a point of light with an apparent visual magnitude of 5.16. The system is located at a distance of 25 light years from the Sun based on parallax, and is moving closer with a high radial velocity of −98 km/s. This star will move into the constellation Perseus around 5200 AD.

<span class="mw-page-title-main">Kappa Cassiopeiae</span> Star in the constellation Cassiopeia

Kappa Cassiopeiae is a star in the constellation Cassiopeia.

<span class="mw-page-title-main">Omicron Cassiopeiae</span> Star in the constellation Cassiopeia

Omicron Cassiopeiae is a triple star system in the constellation Cassiopeia. It is approximately 700 light-years from Earth, based on its parallax. It is visible to the naked eye with a slightly variable apparent magnitude of about 4.5.

48 Cassiopeiae is a triple star system in the northern constellation of Cassiopeia. It is visible to the naked eye with a combined apparent visual magnitude of 4.49. With an annual parallax shift of 28.36±0.44 mas as seen from Earth's orbit, it is located approximately 115 light years away. The system is moving closer with a heliocentric radial velocity of −12.4 km/s.

<span class="mw-page-title-main">Pi Cassiopeiae</span> Variable star in the constellation Cassiopeia

Pi Cassiopeiae, Latinized from π Cassiopeiae, is a close binary star system in the constellation Cassiopeia. It is visible to the naked eye with an apparent visual magnitude of +4.949. Based upon an annual parallax shift of 18.63 mas as seen from Earth, this system is located about 175 light years from the Sun.

<span class="mw-page-title-main">Omega Cassiopeiae</span> Binary star system in constellation Cassiopeia

Omega Cassiopeiae is a binary star system in the northern constellation of Cassiopeia. It has a combined apparent visual magnitude of +4.99, which means it is a faint star but visible to the naked eye. Based upon an annual parallax shift of 4.65 mas as seen from Earth, this system is located roughly 730 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.16 due to interstellar dust.

3 Centauri is a triple star system in the southern constellation of Centaurus, located approximately 300 light years from the Sun. It is visible to the naked eye as a faint, blue-white hued star with a combined apparent visual magnitude of 4.32. As of 2017, the two visible components had an angular separation of 7.851″ along a position angle of 106°. The system has the Bayer designation k Centauri; 3 Centauri is the Flamsteed designation. It is a suspected eclipsing binary with a variable star designation V983 Centauri.

<span class="mw-page-title-main">Zeta Cephei</span> Star in the constellation Cepheus

Zeta Cephei is a star in the constellation of Cepheus. Zeta Cephei marks the left shoulder of Cepheus, the King of Joppa (Ethiopia). It is one of the fundamental stars of the MK spectral sequence, defined as type K1.5 Ib.

Kappa<sup>1</sup> Apodis Star in the constellation Apus

Kappa1 Apodis, Latinized from κ1 Apodis, is the Bayer designation for a binary star system in the southern circumpolar constellation of Apus. Based upon parallax measurements, it is located roughly 1,060 light-years from Earth. The combined apparent visual magnitude of the system is 5.52, indicating that this is a faint, naked eye star that can be viewed in dark suburban skies. It is moving away from the Sun with a radial velocity of +62 km/s.

<span class="mw-page-title-main">LY Aurigae</span> Binary star in the constellation Auriga

LY Aurigae is a multiple star system in the constellation Auriga. It is an eclipsing binary variable star, dropping in brightness by 0.7 magnitudes every 4 days. The system is around a thousand light years away in the Auriga OB1 stellar association.

<span class="mw-page-title-main">S Monocerotis</span> Star in the constellation Monoceros

S Monocerotis, also known as 15 Monocerotis, is a massive multiple and variable star system located in the constellation Monoceros. It is the brightest star in the Christmas Tree open cluster in the area catalogued as NGC 2264.

Lambda Cygni is a class B5V star in the constellation Cygnus. Its apparent magnitude is 4.54 and it is approximately 770 light years away based on parallax.

<span class="mw-page-title-main">42 Persei</span> Binary star system in the constellation Perseus

42 Persei is a binary star system in the northern constellation of Perseus. It has the Bayer designation n Persei, while 42 Persei is the Flamsteed designation. The system is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.11. It is located around 93 parsecs (302 ly) distant from the Sun, but is drifting closer with a radial velocity of −12.4 km/s.

<span class="mw-page-title-main">V3903 Sagittarii</span> Binary star system in the constellation Sagittarius

V3903 Sagittarii is an eclipsing binary star system in the constellation Sagittiarus. It creates an H II region LBN 29 1,070 parsecs away from the Sun.

<span class="mw-page-title-main">AC Herculis</span> Spectroscopic binary star in the constellation Hercules

AC Herculis, is an RV Tauri variable and spectroscopic binary star in the constellation of Hercules. It varies in brightness between apparent magnitudes 6.85 and 9.0.

References

  1. 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. Vizier catalog entry
  2. 1 2 3 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. 1 2 3 Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  4. Sota, A.; Maíz Apellániz, J.; Walborn, N. R.; Alfaro, E. J.; Barbá, R. H.; Morrell, N. I.; Gamen, R. C.; Arias, J. I. (2011). "The Galactic O-Star Spectroscopic Survey. I. Classification System and Bright Northern Stars in the Blue-violet at R ~ 2500". The Astrophysical Journal Supplement. 193 (2): 24. arXiv: 1101.4002 . Bibcode:2011ApJS..193...24S. doi:10.1088/0067-0049/193/2/24. S2CID   119248206.
  5. Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I.; Torres, G.; Udry, S. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727–732. arXiv: astro-ph/0406573 . Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213. S2CID   119387088.
  6. Conti, Peter S.; Alschuler, William R. (1971). "Spectroscopic Studies of O-Type Stars. I. Classification and Absolute Magnitudes". Astrophysical Journal. 170: 325. Bibcode:1971ApJ...170..325C. doi:10.1086/151218.
  7. 1 2 Palate, M.; Rauw, G. (2012). "Spectral modelling of circular massive binary systems. Towards an understanding of the Struve-Sahade effect?". Astronomy & Astrophysics. 537: A119. arXiv: 1109.1103 . Bibcode:2012A&A...537A.119P. doi:10.1051/0004-6361/201117520. S2CID   84840295.
  8. 1 2 3 4 Bagnuolo, W. G.; Gies, D. R. (1992). "Tomographic Separation of Composite Spectra of O-Type Stars". Complementary Approaches to Double and Multiple Star Research. 32: 140. Bibcode:1992ASPC...32..140B.
  9. Struve, O.; Rudkjøbing, M. (1948). "A Note on the Spectrum of HD 698 (j. A. Pearce's Star of Large Mass)". Astrophysical Journal. 108: 537. Bibcode:1948ApJ...108R.537S. doi: 10.1086/145098 .
  10. Hohle, M. M.; Neuhäuser, R.; Schutz, B. F. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv: 1003.2335 , Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID   111387483
  11. Watson, Christopher (4 January 2010). "AO Cassiopeiae". AAVSO Website. American Association of Variable Star Observers . Retrieved 15 February 2014.
  12. Bortle, John E. (February 2001). "The Bortle Dark-Sky Scale". Sky & Telescope . Sky Publishing Corporation. Retrieved 5 February 2014.
  13. Astronomy and Cosmogony. CUP Archive. 1929. pp. 125–. GGKEY:KFJRG3PWW14.