HR 1217

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HR 1217
DOEriLightCurve.png
A light curve for DO Eridani, adapted from Holdsworth et al. (2021) [1]
Observation data
Epoch J2000       Equinox J2000
Constellation Eridanus
Right ascension 03h 55m 16.13133s [2]
Declination −12° 05 56.7277 [2]
Apparent magnitude  (V)5.97 - 6.00 [3]
Characteristics
Spectral type A9Vp SrEuCr [4]
Variable type roAp [5]
Astrometry
Proper motion (μ)RA: −91.357±0.036 [2]   mas/yr
Dec.: −28.376±0.036 [2]   mas/yr
Parallax (π)20.7432 ± 0.0413  mas [2]
Distance 157.2 ± 0.3  ly
(48.21 ± 0.10  pc)
Absolute magnitude  (MV)2.32 [6]
Details
Mass 1.54±0.13 [7]   M
Radius 1.75±0.05 [7]   R
Luminosity 7.6±1.2 [7]   L
Surface gravity (log g)4.30 [8]   cgs
Temperature 7,235±280 [7]   K
Metallicity [Fe/H]−0.36 [8]   dex
Rotation 12.46  d [7]
Rotational velocity (v sin i)7.0 [8]  km/s
Age 780+760
−470
[7]   Myr
Other designations
HD  24712, HIP  18339, HR  1217, SAO  149251, 2MASS J03551613-1205567 [9]
Database references
SIMBAD data

HR 1217 is a variable star in the constellation Eridanus. It has the variable star designation DO Eridani, but this seldom appears in the astronomical literature; it is usually called either HR 1217 or HD 24712. At its brightest, HR 1217 has an apparent magnitude of 5.97, making it very faintly visible to the naked eye for an observer with excellent dark-sky conditions. [5]

HR 1217 is one of the best-studied rapidly oscillating Ap (roAp) stars. [1] Inspired by the 1978 discovery of the rapid (12 minute period) brightness variability of Przybylski's Star (an Ap star), in 1980 D. W. Kurtz observed the Ap star HR 1217, and found clear 6.15 minute oscillations, the amplitude of which slowly changed over the course of several days. [10] The next year, high-speed photometric observations of the star revealed six nearly equally spaced pulsation periods ranging from 6.126 minutes (strongest) to 5.966 minutes (weakest). [11] In 1989 it was found that the amplitudes of these pulsations are modulated over a period equal to the star's rotation period. [12] By 2019, ten pulsation frequencies had been found in the TESS data. [13]

HR 1217 is a chemically peculiar star, with particular over-abundances of copper, europium, and chromium in its spectrum. [4] At the same time, lines of other metals such as iron are less strong than expected for an A9 star, which is typical of an Ap star. In 2009, Shulyak et al. computed a model atmosphere for the star which showed how the elemental abundances varied as a function of atmospheric height. [14] In 2015, doppler imaging was used to produce maps of both the star's magnetic field and the distribution of several chemical elements across the star's surface. It was the first roAp star to be mapped in this way. [15]

Related Research Articles

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<span class="mw-page-title-main">HD 105382</span> Star in the constellation Centaurus

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<span class="mw-page-title-main">Rho Phoenicis</span> Variable star in the constellation Phoenix

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<span class="mw-page-title-main">17 Comae Berenices</span> Multiple star system in the constellation Coma Berenices

17 Comae Berenices is a multiple star system in the northern constellation of Coma Berenices. The brighter component, 17 Com A, is a naked eye star with an apparent visual magnitude of 5.2. It has a faint companion of magnitude 6.6, 17 Com B, positioned at an angular separation of 146.4″ along a position angle of 251°, as of 2018. They are located at a distance of approximately 240 light years from the Sun based on parallax measurements.

HR 7355 is a star in the southern constellation of Sagittarius. It is faintly visible to the naked eye with an apparent visual magnitude of 6.03. The star is located at a distance of approximately 760 light years based on parallax measurements. The radial velocity of the star is poorly constrained, but it appears to be receding at the rate of +4 km/s.

<span class="mw-page-title-main">HD 125248</span> Binary star system in the constellation of Virgo

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<span class="mw-page-title-main">HD 133880</span> Variable star in the constellation Lupus

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<span class="mw-page-title-main">HR 1170</span> Variable star in the constellation Perseus

HR 1170, also known as HD 23728 and V376 Persei, is a star about 220 light years from the Earth, in the constellation Perseus. It is a 5th magnitude star, so it will be faintly visible to the naked eye of an observer far from city lights. It is a variable star, whose brightness varies slightly from magnitude 5.77 to 5.91.

<span class="mw-page-title-main">QQ Telescopii</span> Delta Scuti variable; Telescopium

QQ Telescopii, also known as HD 185139 or simply QQ Tel, is a solitary variable star located in the southern constellation Telescopium. It has an apparent magnitude of 6.25, placing it near the limit for naked eye visibility, even under ideal conditions. Gaia DR3 parallax measurements imply a distance of 333 light years and it is currently receding with a heliocentric radial velocity of 7.8 km/s. At its current distance, QQ Telescopii's brightness is diminished by two tenths of a magnitude due to interstellar dust and it has an absolute magnitude of +1.01.

References

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  11. Kurtz, D. W.; Seeman, J. (October 1983). "Frequency analysis of the rapidly oscillating AP star HR 1217 (HD 24712)". Monthly Notices of the Royal Astronomical Society. 205: 11–22. Bibcode:1983MNRAS.205...11K. doi: 10.1093/mnras/205.1.11 .
  12. Kurtz, D. W.; Matthews, J. M.; Martinez, P.; Seeman, J.; Cropper, M.; Clemens, J. C.; Kreidl, T. J.; Sterken, C.; Schneider, H.; Weiss, W. W.; Kawaler, S. D.; Kepler, S. O. (October 1989). "The high-overtone p-mode spectrum of the rapidly oscillating AP star HR 1217 (HD 24712) - results of a frequency analysis of 324 HR of multi-site photometric observations obtained during a 46-d time-span in 1986". Monthly Notices of the Royal Astronomical Society. 240 (4): 881–915. Bibcode:1989MNRAS.240..881K. doi: 10.1093/mnras/240.4.881 . hdl: 10183/88382 .
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