Lambda Geminorum

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Lambda Geminorum
Observation data
Epoch J2000.0        Equinox J2000.0
Constellation Gemini
Right ascension 07h 18m 05.58012s [1]
Declination +16° 32′ 25.3964″ [1]
Apparent magnitude  (V)3.571 [2]
Characteristics
Spectral type A3V [3]
U−B color index +0.167 [2]
B−V color index +0.113 [2]
Variable type Constant [4]
Astrometry
Radial velocity (Rv)–7.40 [5]  km/s
Proper motion (μ)RA: –44.43 [6]   mas/yr
Dec.: –36.61 [6]   mas/yr
Parallax (π)32.33 ± 0.20  mas [6]
Distance 100.9 ± 0.6  ly
(30.9 ± 0.2  pc)
Absolute magnitude  (MV)+1.13 [7]
Details
Mass 2.098 [3]   M☉
Radius 2.7773±0.0469 [3]   R☉
Luminosity 27.3901±0.3416 [3]   L☉
Temperature 7,932±62 [3]   K
Metallicity [Fe/H]−0.04±0.04 [8]   dex
Rotational velocity (v sin i)154 [9]  km/s
Age 0.8 Gyr [3]
0.5 [10]   Gyr
Other designations
λ Gem, 54 Geminorum, NSV  3512, BD+16 1443, FK5  277, HD  56537, HIP  35350, HR  2763, SAO  96746, WDS J07181+1632A [11]
Database references
SIMBAD data

Lambda Geminorum, Latinized from λ Geminorum, is a candidate multiple star system in the constellation Gemini. It is visible to the naked eye at night with a combined apparent visual magnitude of 3.57. [2] The distance to this system is 101  light years based on parallax, [6] and it is drifting closer with a radial velocity of –7.4 km/s. [5] It is a member of what is suspected to be a trailing tidal tail of the Hyades Stream. [12]

Components A and B of this system form a wide binary. [13] The secondary, component B, is a magnitude 10.7 stellar companion at an angular separation of 9.29″ from the primary along a position angle of 35.72°, as of 2009. The primary was identified as a spectroscopic binary by E. B. Frost in 1924. [14] This companion was confirmed during a lunar occultation with a separation of 14.1±0.7  mas and magnitude 6.8. [15]

The primary, designated component A, typically has been assigned a stellar classification of A3V, [3] which indicates this is an A-type main-sequence star that generates energy from core hydrogen fusion. However, in 1970 D. C. Barry classed it as A4IV, [16] suggesting this may be a subgiant star that has begun evolving into a giant star. It was catalogued a suspected variable star, but is now confirmed as constant. [4]

This star is less than a billion years in age with a rapid spin, showing a projected rotational velocity of 154 km/s [9] It is larger and hotter than the Sun, with twice the Sun's mass and 2.8 times the radius of the Sun. The star is radiating 27 times the Sun's luminosity from its photosphere at an effective temperature of 7,932 K. [3]

The primary displays a significant infrared excess in the K-band, which indicates an orbiting circumstellar disk of dust. A model fit to the data shows an inner radius between 0.08  AU and 0.14 AU, and an outer radius of up to 0.65 AU. [10]

Related Research Articles

<span class="mw-page-title-main">Castor (star)</span> Sextuple star system in Gemini

Castor is the second-brightest object in the zodiac constellation of Gemini. It has the Bayer designation α Geminorum, which is Latinised to Alpha Geminorum and abbreviated Alpha Gem or α Gem. With an apparent visual magnitude of 1.93, it is one of the brightest stars in the night sky. Castor appears singular to the naked eye, but it is actually a sextuple star system organized into three binary pairs. Although it is the 'α' (alpha) member of the constellation, it is fainter than 'β' (beta) Geminorum, Pollux.

Psi Scorpii, which is Latinized from ψ Scorpii, is a star in the zodiac constellation of Scorpius. It is white in hue and has an apparent visual magnitude of 4.94, which is bright enough to be faintly visible to the naked eye. Based upon parallax measurements, it is located at a distance of around 162 light years from the Sun. Data collected during the Hipparcos mission suggests it is an astrometric binary, although nothing is known about the companion. The system is drifting closer to the Sun with a radial velocity of −5 km/s.

Upsilon Serpentis, Latinized from υ Serpentis, is a star in the Serpens Caput section of the constellation Serpens. Based upon an annual parallax shift of 13.04 mas as seen from Earth, it is located around 250 light years from the Sun. The star is bright enough to be faintly visible to the naked eye, having an apparent visual magnitude of +5.70. It is a member of the Hyades group, a stream of stars that share a similar trajectory to the Hyades cluster.

<span class="mw-page-title-main">R Hydrae</span> Variable star in the constellation Hydra

R Hydrae, abbreviated R Hya, is a single star in the equatorial constellation of Hydra, about 2.7° to the east of Gamma Hydrae. It is a Mira-type variable that ranges in apparent visual magnitude from 3.5 down to 10.9 over a period of 389 days. At maximum brightness the star can be seen with the naked eye, while at minimum a telescope of at least 5 cm is needed. This star is located at a distance of approximately 410 light-years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −10 km/s.

Chi Cancri, Latinized from χ Cancri, is a candidate astrometric binary star system in the northern zodiac constellation of Cancer. It has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.14. The system is located at a distance of 59 light years from the Sun, based on parallax, and is drifting further away with a radial velocity of +33 km/s. It is estimated to have made its closest approach some 274,000 years ago when it came to within 42 light-years.

3 Cancri is a single star in the zodiac constellation of Cancer, located around 810 light years from the Sun. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.60. This object is moving further from the Earth with a heliocentric radial velocity of +39.5 km/s, and may be a member of the Hyades group. It is located near the ecliptic and thus is subject to lunar eclipses.

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.

2 Ursae Minoris is a single star a few degrees away from the northern celestial pole. Despite its Flamsteed designation, the star is actually located in the constellation Cepheus. This changed occurred when the constellation boundaries were formally set in 1930 by Eugene Delporte. Therefore, the star is usually referred only by its catalog numbers such as HR 285 or HD 5848. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.244. This object is located 280 light years away and is moving further from the Earth with a heliocentric radial velocity of +8 km/s. It is a candidate member of the Hyades Supercluster.

<span class="mw-page-title-main">Iota Lyrae</span> Binary star in the constellation Lyra

ι Lyrae, Latinised as Iota Lyrae, is a binary star in the northern constellation of Lyra. It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude that fluctuates around 5.22. This object is located approximately 910 light years distant from the Sun based on parallax, but is drifting nearer with a radial velocity of −26 km/s.

HD 217382 is a suspected binary star system in the northern circumpolar constellation of Cepheus. It is faintly visible to the naked eye with an apparent visual magnitude of 4.70. The distance to HD 217382 is around 373 light years, as determined from an annual parallax shift of 8.74 mas. The system is moving further away with a heliocentric radial velocity of +2.6 km/s. It is a candidate member of the Hyades supercluster and has a peculiar velocity of 9.2 km/s.

<span class="mw-page-title-main">Rho Geminorum</span> Star system in the constellation Gemini

Rho Geminorum is a star system that lies 59 light-years away in the constellation of Gemini, about 5 arcminutes east of Castor. The system consists of a primary bright enough to be seen with the naked eye, a faint secondary which has rarely been observed even professionally, and a distant, somewhat bright tertiary which requires telescopic equipment for observation.

38 Geminorum is a binary star system in the northern zodiac constellation of Gemini. It has the Bayer designation e Geminorum, while 38 Geminorum is the Flamsteed designation. This system is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.71. The primary component is a magnitude 4.75 star, while the secondary is magnitude 7.80. The system is located about 98 light years away from the Sun based on parallax, and is drifting further away with a radial velocity of +16 km/s. It is a potential member of the Tucana–Horologium stellar kinematic group.

<span class="mw-page-title-main">81 Geminorum</span> Star in the constellation Gemini

81 Geminorum is a binary star system in the northern constellation of Gemini. It has the Bayer designation g Geminorum, while 81 Geminorum is its Flamsteed designation. This system is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.89. The pair are located approximately 360 light years away from the Sun, based on parallax, and are moving further away with a radial velocity of +83 km/s, having come to within an estimated 164 light-years of the Earth nearly a million years ago. 81 Geminorum lies close enough to the ecliptic to undergo lunar occultations.

90 Tauri is a star in the zodiac constellation of Taurus, located 144 light-years away from the Sun. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.27. 90 Tauri is a member of the Hyades cluster and is listed as a double star.

<span class="mw-page-title-main">HD 21278</span> Binary star system in the constellation Perseus

HD 21278 is a binary star system in the constellation Perseus, located within the 60±7 million year old Alpha Persei Cluster. It has a blue-white hue and is visible to the naked eye with a combined apparent visual magnitude of 4.99. The system is located at a distance of approximately 580 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of +1.20 km/s.

<span class="mw-page-title-main">43 Persei</span> Spectroscopic binary star system in the constellation Perseus

43 Persei is a binary star system in the northern constellation Perseus. It is visible to the naked eye as a dim, yellow-white hued star with an apparent visual magnitude of 5.28. The system is located around 38.5 parsecs (125.4 ly) distant from the Sun, based on parallax.

<span class="mw-page-title-main">31 Persei</span> Star in the constellation Perseus

31 Persei is a single star in the northern constellation of Perseus. It is visible to the naked eye as a dim, blue-white hued point of light with an apparent visual magnitude of 5.05. This star is located around 172 parsecs (560 ly) away from the Sun, and it is drifting closer with a radial velocity of −1.6 km/s. It is likely a member of the Alpha Persei Cluster.

Sigma1 Gruis, a Latinization of σ1 Gruis, is a star in the constellation Grus. It is a dim, white-hued star near the lower limit for visibility to the naked eye with an apparent visual magnitude of 6.26. This object is located 229 light-years (70.1 pc) distant from the Sun based on parallax. The radial velocity of this star is poorly constrained, but it appears to be drifting further away at the rate of +7 km/s.

16 Delphini is a star in the equatorial constellation Delphinus. It has an apparent magnitude of 5.54, making it faintly visible to the naked eye. The star is relatively close at a distance of 198 light years but is receding with a poorly constrained radial velocity of 2 km/s.

<span class="mw-page-title-main">72 Tauri</span> Star in the constellation of Taurus

72 Tauri is a possible binary star in the zodiac constellation of Taurus. It is faintly visible to the naked eye with an apparent visual magnitude of +5.5, although only 0.29° from the brighter υ Tauri. Based upon an annual parallax shift of 7.9 mas seen from Earth, it is around 410 light years from the Sun.

References

  1. 1 2 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR.
  2. 1 2 3 4 Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile, Publicaciones Universidad de Chile, Department de Astronomy, 1: 1–17, Bibcode:1966PDAUC...1....1G.
  3. 1 2 3 4 5 6 7 8 Boyajian, Tabetha S.; et al. (July 2013), "Stellar Diameters and Temperatures. III. Main-sequence A, F, G, and K Stars: Additional High-precision Measurements and Empirical Relations", The Astrophysical Journal, 771 (1): 40, arXiv: 1306.2974 , Bibcode:2013ApJ...771...40B, doi:10.1088/0004-637X/771/1/40, S2CID   14911430.
  4. 1 2 "Lam Gem". The International Variable Star Index. AAVSO – American Association of Variable Star Observers. Retrieved March 29, 2017.
  5. 1 2 Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35 495 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.
  6. 1 2 3 4 van Leeuwen, F. (November 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.
  7. ↑ 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, S2CID   119257644.
  8. ↑ Cheng, Kwang-Ping; et al. (April 2016), "Utilizing Synthetic UV Spectra to Explore the Physical Basis for the Classification of Lambda Boötis Stars", The Astronomical Journal, 151 (4): 17, Bibcode:2016AJ....151..105C, doi: 10.3847/0004-6256/151/4/105 , S2CID   124045100, 105.
  9. 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.
  10. 1 2 Kirchschlager, Florian; et al. (May 2017), "Constraints on the structure of hot exozodiacal dust belts", Monthly Notices of the Royal Astronomical Society, 467 (2): 1614–1626, arXiv: 1701.07271 , Bibcode:2017MNRAS.467.1614K, doi:10.1093/mnras/stx202.
  11. ↑ "* lam Gem". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2006-12-09.
  12. ↑ Röser, Siegfried; et al. (January 2019), "Hyades tidal tails revealed by Gaia DR2", Astronomy & Astrophysics, 621: 5, arXiv: 1811.03845 , Bibcode:2019A&A...621L...2R, doi:10.1051/0004-6361/201834608, S2CID   118909033, L2.
  13. ↑ Rodriguez, David R.; et al. (May 2015), "Stellar multiplicity and debris discs: an unbiased sample", Monthly Notices of the Royal Astronomical Society, 449 (3): 3160–3170, arXiv: 1503.01320 , Bibcode:2015MNRAS.449.3160R, doi:10.1093/mnras/stv483, S2CID   119237891.
  14. ↑ Frost, E. B. (December 1924), "Fourteen spectroscopic binaries", Astrophysical Journal, 60: 319–320, Bibcode:1924ApJ....60..319F, doi:10.1086/142868.
  15. ↑ Richichi, A.; et al. (October 1999), "New binary stars discovered by lunar occultations. IV", Astronomy and Astrophysics, 350: 491−496, Bibcode:1999A&A...350..491R.
  16. ↑ Barry, Don C. (January 1970), "Spectral Classification of a and F Stars", Astrophysical Journal Supplement, 19: 281, Bibcode:1970ApJS...19..281B, doi:10.1086/190209.
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