V473 Lyrae

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V473 Lyrae
Lyra constellation map.svg
Red circle.svg
Location of V473 Lyrae (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Lyra
Right ascension 19h 15m 59.48949s [1]
Declination +27° 55 34.6870 [1]
Apparent magnitude  (V)5.99 - 6.35 [2]
Characteristics
Spectral type F7 II [3]
U−B color index +0.272 - +0.392
B−V color index +0.554 - +0.750 [4]
Variable type δ Cep [2]
Astrometry
Proper motion (μ)RA: 4.31 ± 0.22 [1]   mas/yr
Dec.: 0.63 ± 0.34 [1]   mas/yr
Parallax (π)2.33 ± 0.32  mas [1]
Distance 553 [5]   pc
Absolute magnitude  (MV)2.5 [6]
Details
Mass 3.0 - 4.6 [6]   M
Radius 24 [6]   R
Luminosity 740 [6]   L
Surface gravity (log g)2.14 [7]   cgs
Temperature 6,190 [7]   K
Metallicity [Fe/H]0.13 [7]   dex
Other designations
BD+27° 3314, V473  Lyrae, SAO  87008, HD  180583, HIP  94685, HR  7308
Database references
SIMBAD data

V473 Lyrae is a variable star in the constellation Lyra. It is an unusual Classical Cepheid variable with a visual range of 5.99 to 6.35.

Contents

Discovery

V473 Lyrae is a faint naked eye star, but its brightness variations were not reported until 1968. It was noted to be possibly variable, [8] then examined as a possible δ Sct variable. It was confirmed as variable but the variations were considered semi-regular and so it was not catalogued as a δ Sct variable. [9]

In 1979, brightness variations were again noticed and V473 was listed as a short-period Cepheid, although the period was thought to be 3.04 days. The correct period was found a few years later at 1.49078 days, at the time the shortest known period for a galactic Cepheid. Unusual periodic variations in the pulsation amplitude were also noticed, similar to the Blazhko effect in RR Lyrae variables. [10]

Pulsations

A blue band light curve for V473 Lyrae, adapted from Kiss (1998) V473LyrLightCurve.png
A blue band light curve for V473 Lyrae, adapted from Kiss (1998)

The unusually short period of V473 Lyr is caused by pulsations in the second overtone and the fundamental pulsation period would be three times as long. [6] The amplitude variations have an approximate period of 1,205 days, and there is a secondary modulation with a period of 5,300 days. [10]

Companion

V473 Lyrae has a faint companion. Although the two stars are separated by 15", the companion is 15th magnitude and so faint that it is difficult to detect next to the naked eye primary. At the distance of V473 Lyrae, the separation corresponds to 8,300 astronomical units. [5]

X-rays

X-rays have been detected from V473 Lyrae during a survey looking for x-rays from young main sequence companions to Cepheid variables. However, the x-rays in this case appear to originate from the Cepheid itself, not from the companion. There may be a closer unseen companion or the x-rays may have another cause. [12]

Related Research Articles

<span class="mw-page-title-main">RR Lyrae variable</span> Type of variable star

RR Lyrae variables are periodic variable stars, commonly found in globular clusters. They are used as standard candles to measure (extra) galactic distances, assisting with the cosmic distance ladder. This class is named after the prototype and brightest example, RR Lyrae.

<span class="mw-page-title-main">Eta Aquilae</span> Multiple star in the constellation Aquila

Eta Aquilae is the Bayer designation for a multiple star in the equatorial constellation of Aquila, the eagle. It was once part of the former constellation Antinous. On average, this star has an apparent visual magnitude of 3.87, making it one of the brighter members of Aquila. Based upon parallax measurements made during the Hipparcos mission, this star is located at a distance of roughly 1,382 light-years, although the parallax estimate has a 44% margin of error.

<span class="mw-page-title-main">W Sagittarii</span> Star in the constellation Sagittarius

W Sagittarii is a multiple star system star in the constellation Sagittarius, and a Cepheid variable star.

<span class="mw-page-title-main">RT Aurigae</span> Star in the constellation Auriga

RT Aurigae is a yellow supergiant variable star in the constellation Auriga, about 1,500 light years from Earth.

<span class="mw-page-title-main">Y Carinae</span> Star in the constellation Carina

Y Carinae is a Classical Cepheid variable, a type of variable star, in the constellation Carina. Its apparent magnitude varies from 7.53 to 8.48.

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

S Normae is a yellow supergiant variable star in the constellation Norma. It is the brightest member of the open cluster NGC 6087.

<span class="mw-page-title-main">FF Aquilae</span> Star and possible star system in the constellation Aquila

FF Aquilae is a classical Cepheid variable star located in the constellation Aquila. It ranges from apparent magnitude 5.18 to 5.51 over a period of 4.470848 days, meaning it is faintly visible to the unaided eye in rural or suburban settings.

<span class="mw-page-title-main">TT Aquilae</span> Star in the constellation Aquila

TT Aquilae is a Classical Cepheid variable star in the constellation Aquila.

<span class="mw-page-title-main">Type II Cepheid</span>

Type II Cepheids are variable stars which pulsate with periods typically between 1 and 50 days. They are population II stars: old, typically metal-poor, low mass objects.

<span class="mw-page-title-main">Classical Cepheid variable</span>

Classical Cepheids are a type of Cepheid variable star. They are young, population I variable stars that exhibit regular radial pulsations with periods of a few days to a few weeks and visual amplitudes ranging from a few tenths of a magnitude up to about 2 magnitudes. Classical Cepheids are also known as Population I Cepheids, Type I Cepheids, and Delta Cepheid variables.

<span class="mw-page-title-main">Kappa Pavonis</span> Variable star in the constellation Pavo

Kappa Pavonis is a variable star in the constellation Pavo. It is the brightest W Virginis variable in the sky.

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

R Muscae is a yellow-white hued variable star in the southern constellation of Musca. It has a nominal apparent visual magnitude of 6.31, which is near the lower limit of visibility to the naked eye. The distance to this star, as determined from its annual parallax shift of 1.00 mas, is around 3,260 light years.

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

S Muscae is a classical (δ) Cepheid variable star in the constellation Musca about 2,600 light years away.

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

R Crucis is a variable star in the southern constellation of Crux. It has a yellow-white hue and is often too faint to see with the naked eye, having an apparent visual magnitude that fluctuates around 6.89. This object is located at a distance of approximately 1,600 light years from the Sun based on parallax, but it is drifting closer with a radial velocity of −13.5 km/s.

<span class="mw-page-title-main">RU Camelopardalis</span> Star in the constellation Camelopardalis

RU Camelopardalis, or RU Cam, is a W Virginis variable in the constellation of Camelopardalis. It is also a Carbon star, which is very unusual for a Cepheid variable.

<span class="mw-page-title-main">SZ Tauri</span>

SZ Tauri is a variable star in the equatorial constellation of Taurus. The brightness of this star varies from an apparent visual magnitude of 6.39 down to 6.69 with a period of 3.149 days, which is near the lower limit of visibility to the naked eye. The distance to this star is approximately 2,070 light years based on parallax measurements. There is some indication this may be a binary system, but the evidence is inconclusive.

<span class="mw-page-title-main">VZ Cancri</span> Variable star in the constellation Cancer

VZ Cancri is a variable star in the constellation Cancer, abbreviated VZ Cnc. It varies in brightness with a period of 0.178364 days, from an apparent visual magnitude of 7.18 down to 7.91, which lies below the typical threshold of visibility for the naked eye. The distance to this star is approximately 724 light years based on parallax measurements, and it is receding from the Sun with a radial velocity of 25 km/s.

<span class="mw-page-title-main">U Sagittarii</span> Star in the constellation Sagittarius

U Sagittarii is a variable star in the southern constellation of Sagittarius, abbreviated U Sgr. It is a classical Cepheid variable that ranges in brightness from an apparent visual magnitude of 6.28 down to 7.15, with a pulsation period of 6.745226 days. At its brightest, this star is dimly visible to the naked eye. The distance to this star is approximately 2,080 light years based on parallax measurements, and it is drifting further away with a radial velocity of 2 km/s.

<span class="mw-page-title-main">X Cygni</span> Variable star in the constellation Cygnus

X Cygni is a variable star in the northern constellation of Cygnus, abbreviated X Cyg. This is a Delta Cephei variable that ranges in brightness from an apparent visual magnitude of 5.85 down to 6.91 with a period of 16.386332 days. At it brightest, this star is dimly visible to the naked eye. The distance to this star is approximately 628 light years based on parallax measurements. It is drifting further away with a radial velocity of 8.1 km/s. This star is a likely member of the open cluster Ruprecht 173.

<span class="mw-page-title-main">SU Cygni</span> Variable star system in the constellation Cygnus

SU Cygni is a triple star system in the northern constellation of Cygnus, abbreviated SU Cyg. The primary component of the system is a classical Cepheid variable with a period of 3.8455473 days. The changing luminosity of this star causes the system to vary in brightness from a peak apparent visual magnitude of 6.44 down to magnitude 7.22 over the course of its cycle. The distance to this system is approximately 3,200 light years based on parallax measurements. It is a member of the Turner 9 open cluster of stars.

References

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  5. 1 2 Evans, Nancy Remage; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.; Tingle, Evan; Karovska, Margarita; Pillitteri, Ignazio (2016). "Hubble Space Telescope Snapshot Survey for Resolved Companions of Galactic Cepheids". The Astronomical Journal. 151 (5): 129. arXiv: 1603.02224 . Bibcode:2016AJ....151..129E. doi:10.3847/0004-6256/151/5/129. S2CID   119248298.
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  7. 1 2 3 Gray, R. O.; Graham, P. W.; Hoyt, S. R. (2001). "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. II. Basic Parameters of Program Stars and the Role of Microturbulence". The Astronomical Journal. 121 (4): 2159. Bibcode:2001AJ....121.2159G. doi: 10.1086/319957 .
  8. Breger, M. (1968). "UBV and narrow-band UVBY photometry of bright stars". Astronomical Journal. 73: 84. Bibcode:1968AJ.....73...84B. doi:10.1086/110602.
  9. Breger, Michel (1969). "Short-Period Variability of b, a, and F Stars. III. A Survey of Delta Scuti Variable Stars". Astrophysical Journal Supplement. 19: 79. Bibcode:1969ApJS...19...79B. doi:10.1086/190199.
  10. 1 2 Molnar, L.; Szabados, L. (2014). "V473 Lyrae, a unique second-overtone Cepheid with two modulation cycles". Monthly Notices of the Royal Astronomical Society. 442 (4): 3222–3234. arXiv: 1406.0494 . Bibcode:2014MNRAS.442.3222M. doi:10.1093/mnras/stu1091. S2CID   118591859.
  11. Kiss, Laszlo L. (July 1998). "A photometric and spectroscopic study of the brightest northern Cepheids - I. Observations". Monthly Notices of the Royal Astronomical Society. 297 (3): 825. Bibcode:1998MNRAS.297..825K. doi: 10.1046/j.1365-8711.1998.01559.x .
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