Lambda Andromedae

From Wikipedia, the free encyclopedia
(Redirected from Λ Andromedae)
Jump to navigation Jump to search

Template:Short description

Lambda Andromedae
Template:Location mark
Location of λ Andromedae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 3.65 - 4.05[2]
Characteristics
Evolutionary stage subgiant[3]
Spectral type G8 IV[3]
U−B Template:Engvar +0.688[4]
B−V Template:Engvar +0.996[4]
Variable type RS CVn[2]
Astrometry
Radial velocity (Rv)+6.8[5] km/s
Proper motion (μ) RA: Script error: No such module "val".[1] mas/yr
Dec.: Script error: No such module "val".[1] mas/yr
Parallax (π)38.5736±0.1179 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)1.91[6]
Orbit[7]
PrimaryA
CompanionB
Period (P)Script error: No such module "val". days
Semi-major axis (a)Script error: No such module "val".
Eccentricity (e)Script error: No such module "val".
Periastron epoch (T)Script error: No such module "val".
Argument of periastron (ω)
(primary)		Script error: No such module "val".°
Semi-amplitude (K1)
(primary)		Script error: No such module "val". km/s
Details
A
MassScript error: No such module "val".[7] Template:Solar mass
RadiusScript error: No such module "val".[8] Template:Solar radius
Luminosity28.8[8] Template:Solar luminosity
Surface gravity (log g)Script error: No such module "val".[9] cgs
TemperatureScript error: No such module "val".[7] K
Metallicity [Fe/H]−0.56[10] dex
RotationScript error: No such module "val".[7] days
Rotational velocity (v sin i)7.3[11] km/s
B
MassScript error: No such module "val".[7] Template:Solar mass
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[12]
Database references
SIMBADdata

Script error: No such module "Check for unknown parameters".

Lambda Andromedae, Latinized from λ Andromedae, also named Udkadua,[13] is a binary star system in the northern constellation of Andromeda. At an estimated distance of approximately Script error: No such module "convert". from Earth,[1] it has an apparent visual magnitude of around +3.8.[4] This is bright enough to be seen with the naked eye. The system is drifting further away from the Sun with a radial velocity of +6.8 km/s.[5]

Naming

File:Lambda Andromedae.jpg
λ Andromedae in optical light

This star represented the heel of the ancient Sumerian constellation Udkadua, "the storm demon with the gaping mouth". The IAU Working Group on Star Names approved the name Udkadua for this star on 8 May 2025 and it is now so entered in the IAU Catalog of Star Names.[13]

In traditional Arabic astronomy, the stars ι Andromedae, κ Andromedae, and λ Andromedae were known as Kaff al-Musalsala, the hand of the chained woman (i.e. Andromeda), and as Ra’s al-Nāqa, the head of the she-camel.[14]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Flying Serpent, refers to an asterism consisting of λ Andromedae, α Lacertae, 4 Lacertae, π2 Cygni, π1 Cygni, HD 206267, ε Cephei, β Lacertae, σ Cassiopeiae, ρ Cassiopeiae, τ Cassiopeiae, AR Cassiopeiae, 9 Lacertae, 3 Andromedae, 7 Andromedae, 8 Andromedae, κ Andromedae, ι Andromedae, and ψ Andromedae. Consequently, the Chinese name for λ Andromedae itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx).[15]

Properties

File:LambdaAndLightCurve.png
A light curve for Lambda Andromedae, plotted from Hipparcos data[16]

Lambda Andromedae is a single-lined spectroscopic binary with an orbital period of 20.52 days.[7] The spectrum of the primary matches a stellar classification of G8 IV, meaning that it is an evolved star that is in the subgiant stage.[3] The mass of this star is about 50% larger than that of the Sun,[7] but it has expanded to around seven times the Sun's radius. It is radiating over 28[8] times the luminosity of the Sun from its outer envelope at an effective temperature of 4,800 K,[9] giving it the characteristic yellow hue of a G-type star.

This is an RS Canum Venaticorum variable and its brightness varies by 0.225 magnitudes, reaching a maximum of 3.70, with a period of 53.952 days.[17] Such variability is theorized to occur because of tidal friction, which results in chromospheric activity. However, the orbit of this system is nearly circular, so the cause of this system's variability remains uncertain.[17] The X-ray luminosity of this star, as measured by the ROSAT satellite, is Script error: No such module "val"..[9] A magnetic field with an average strength of Script error: No such module "val". has been detected on this star, which is stronger than the field on the Sun.[3] Starspots on the star's surface have been resolved with Doppler imaging.[7]

The secondary has a very low mass of about Template:Solar mass. It is most likely an L-type brown dwarf.[7]

Evolution

Many different spectral classes have been published for λ Andromedae, ranging from G6 to K1. Most sources give a luminosity class of III (giant) or IV (subgiant).[18] Analysis of the physical properties of the star, including its temperature, luminosity, magnetic field, and stellar wind, show that it has recently experienced the first dredge-up and has begun to ascend the red giant branch although it still has a hot corona and is classified as a subgiant by some definitions.[9][3]

References

<templatestyles src="Reflist/styles.css" />

  1. ↑ a b c d e f Template:Cite Gaia DR3
  2. ↑ a b Script error: No such module "citation/CS1".
  3. ↑ a b c d e Script error: No such module "citation/CS1".
  4. ↑ a b c Script error: No such module "citation/CS1".
  5. ↑ a b Script error: No such module "citation/CS1".
  6. ↑ Script error: No such module "citation/CS1".
  7. ↑ a b c d e f g h i Script error: No such module "citation/CS1".
  8. ↑ a b c Script error: No such module "citation/CS1".
  9. ↑ a b c d Script error: No such module "citation/CS1".
  10. ↑ Script error: No such module "citation/CS1".
  11. ↑ Script error: No such module "citation/CS1".
  12. ↑ Template:Cite simbad
  13. ↑ a b Script error: No such module "citation/CS1".
  14. ↑ Script error: No such module "citation/CS1".
    Script error: No such module "citation/CS1".
  15. ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 7 日 Template:Webarchive
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ a b Script error: No such module "citation/CS1".
  18. ↑ Script error: No such module "citation/CS1".

Script error: No such module "Check for unknown parameters".

External links

Template:Stars of Andromeda

Retrieved from "http://debianws.lexgopc.com/wiki143/index.php?title=Lambda_Andromedae&oldid=1940253"