PV Telescopii variable

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A light curve for PV Telescopii, adapted from Jeffery et al. (2020) PVTelLightCurve.png
A light curve for PV Telescopii, adapted from Jeffery et al. (2020)

PV Telescopii variable is a type of variable star that is established in the General Catalogue of Variable Stars with the acronym PVTEL. This class of variables are defined as "helium supergiant Bp stars with weak hydrogen lines and enhanced lines of He and C". [2] That is, the hydrogen spectral lines of these stars are weaker than normal for a star of stellar class B, while the lines of helium and carbon are stronger. They are a type of extreme helium star.

Contents

The prototype for this category of variable is PV Telescopii, which undergoes small but complex luminosity variations and radial velocity fluctuations. [3] The PV Tel stars are extremely hydrogen-deficient compared to other B-class stars and vary in luminosity on time scales ranging from a few hours to several years. [4] As of 2008, there are twelve confirmed PV Tel variables in the General Catalogue of Variable Stars. [2]

PV Telescopii variables are subdivided into three distinct types on the basis of spectral type: type I represents late B and A stars, type II represents O and early B, and type III represents F and G stars. The type III stars are always carbon-rich and hydrogen-deficient, while the type I and II stars do not necessarily have an excess of carbon. The hotter types pulsate more quickly than the cooler types. [5]

List

The following list contains selected PV Telescopii variable that are of interest to amateur or professional astronomy. Unless otherwise noted, the given magnitudes are in the V-band.[ citation needed ]

Star
Maximum
magnitude
Minimum
magnitude
TypeSpectral
type
Upsilon Sagittarii 4.434.65I [n 1] F2p
HD 182040 6.957.17IIIC...
HM Librae 7.427.63IIIC
KS Persei 7.607.85IA5Iap
PV Telescopii 9.249.40IB5p
BD +1 4381 9.479.60IF
CD -35 11760 9.629.83IB4Ibe
HD 160641 9.7810.08IIsdOC9.5II-III_He40
DN Leonis 9.9110.00IIBp
HD 124448 9.9410.03IIB3p
NO Serpentis 10.2710.39IB
V1920 Cygni 10.3010.41IB2/3
CPD -58 2721 10.4010.60IB+...
BD -9 4395 10.4410.63IIB
LS IV -1 2 10.9511.05IOB+

Notes

Related Research Articles

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<span class="mw-page-title-main">R Coronae Borealis</span> Variable star in the constellation Corona Borealis

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<span class="mw-page-title-main">RV Tauri variable</span> Class of luminous variable star

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Alpha Telescopii, Latinized from α Telescopii, is the brightest star in the southern constellation of Telescopium, with an apparent visual magnitude of 3.5. The ancient Roman astronomer Ptolemy included it in the constellation Corona Australis, but it was moved to Telescopium when that constellation was created by French astronomer Nicolas Louis de Lacaille in the 18th century. Parallax measurements put it at a distance of 278 light-years from Earth. At that range, the visual magnitude of the star is diminished by an extinction of 0.22 due to interstellar dust.

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<span class="mw-page-title-main">PV Telescopii</span> Star in the constellation Telescopium

PV Telescopii, also known as HD 168476, is a variable star in the southern constellation of Telescopium. It is too dim to be visible to the naked eye, having an apparent visual magnitude that has been measured varying from 9.24 down to 9.40. The star is the prototype of a class of objects called PV Telescopii variables. It is located at an estimated distance of approximately 23 kilolight-years from the Sun, but is drifting closer with a radial velocity of −169 km/s.

<span class="mw-page-title-main">V1429 Aquilae</span> Star in the constellation Aquila

V1429 Aquilae is a candidate luminous blue variable multiple star system located in the constellation of Aquila. It is often referred to by its Mount Wilson Observatory catalog number as MWC 314. It is a hot luminous star with strong emission lines in its spectrum.

<span class="mw-page-title-main">BX Circini</span> Star in the constellation Circinus

BX Circini is a star in the constellation Circinus. Its variability was discovered in 1995, with its apparent magnitude ranging from 12.57 to 12.62 over a period of 2 hours 33 minutes. It is currently classified as a PV Telescopii variable star, but has been put forward as the prototype of a new class of pulsating star—the BX Circini variables—along with the only other known example, V652 Herculis. This class of star is rare, possibly because this is a brief stage of stellar evolution. Its mass has been calculated to be around 40 percent that of the Sun, but the radius is a few times larger than that of the Sun. The average surface temperature is high, and has been measured at 23,390 ± 90 K using optical spectra, but 1750 K cooler if analysing it in both the visual and ultraviolet. The temperature appears to vary by 3450 K.

<span class="mw-page-title-main">RS Telescopii</span> Star in the constellation Telescopium

RS Telescopii, abbreviated RS Tel, is a variable star in the southern constellation of Telescopium. It is a dim star with an apparent visual magnitude of 10.67, which is much too faint to be visible without a telescope. The variability of this star was discovered by Evelyn F. Leland and announced by Edward C. Pickering in 1910. It was first studied by Cecilia H. Payne in 1928 at the Harvard College Observatory.

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

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<span class="mw-page-title-main">HR 6819</span> Star system in the constellation of Telescopium

HR 6819, also known as HD 167128 or QV Telescopii, is a double star system in the southern constellation of Telescopium. It is in the south-western corner of the constellation, near Pavo to the south and Ara to the west. The system appears as a variable star that is dimly visible to the naked eye with an apparent magnitude that ranges from 5.32 down to 5.39, which is comparable to the maximum brightness of the planet Uranus. It is about 1,120 light years from the Sun, and is drifting farther away at a rate of 9.4 km/s. Due to its location in the sky, it is visible only to observers south of 33°N latitude.

<span class="mw-page-title-main">Hydrogen-deficient star</span> Star that has little or no hydrogen in its atmosphere

A hydrogen-deficient star is a type of star that has little or no hydrogen in its atmosphere. Hydrogen deficiency is unusual in a star, as hydrogen is typically the most common element in a stellar atmosphere. Despite being rare, there are a variety of star types that display a hydrogen deficiency.

<span class="mw-page-title-main">DY Centauri</span> Star in the constellation Centaurus

DY Centauri is a variable star in the constellation Centaurus. From its brightness, it is estimated to be 7000 parsecs (23000 light-years) away from Earth.

References

  1. Jeffery, C. Simon; Barentsen, Geert; Handler, Gerald (June 2020). "TESS photometry of extreme helium stars PV Tel and V821 Cen". Monthly Notices of the Royal Astronomical Society. 495 (1): L135–L138. arXiv: 2006.00946 . Bibcode:2020MNRAS.495L.135J. doi: 10.1093/mnrasl/slaa075 .
  2. 1 2 Jeffery, C. Simon (March 2008). "Variable Star Designations for Extreme Helium Stars". Information Bulletin on Variable Stars. 5817 (1). Bibcode:2008IBVS.5817....1J.
  3. Walker, H. J.; Hill, P. W. (August 1985). "Radial velocities for the hydrogen-deficient star HD 168476, several helium-strong and helium-weak stars". Astronomy and Astrophysics Supplement Series . 61: 303–311. Bibcode:1985A&AS...61..303W.
  4. Jeffery, C. S.; Heber, U. (July 1992). "The extreme helium star BD-9 deg 4395". Astronomy and Astrophysics. 260 (1–2): 133–150. Bibcode:1992A&A...260..133J.
  5. Otero, S. A.; Watson, C.; Wils, P. "Variable Star Type Designations in the VSX". AAVSO Website. American Association of Variable Star Observers . Retrieved 19 July 2014.