HD 75747

Last updated
HD 75747
Chamaeleon constellation map.svg
Red circle.svg
Location of HD 75747 (circled)
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Chamaeleon
Right ascension 08h 43m 12.19841s [1]
Declination −79° 04′ 12.3685″ [1]
Apparent magnitude  (V)6.02 to 6.68 [2]
Characteristics
Spectral type A8 IV + A8 IV [3]
U−B color index +0.08 [4]
B−V color index +0.24 [4]
Variable type Algol + δ Scuti [2]
Astrometry
Radial velocity (Rv)16.1±4.3 [5]  km/s
Proper motion (μ)RA: −27.263  mas/yr [1]
Dec.: +28.179  mas/yr [1]
Parallax (π)10.137 ± 0.0213  mas [1]
Distance 321.7 ± 0.7  ly
(98.6 ± 0.2  pc)
Absolute magnitude  (MV)+1.21 [6]
Orbit
Period (P)1.6699  d [7]
Semi-major axis (a)9.14 R☉ [8]
Eccentricity (e)0.00 [7]
Inclination (i)83.4 [8] °
Periastron epoch (T)2,438,380.526  JD [7]
Argument of periastron (ω)
(secondary)		0.00°
Semi-amplitude (K1)
(primary)		136.1 [7] km/s
Semi-amplitude (K2)
(secondary)		138.9 [7] km/s
Details
Luminosity 17.3±1.2 [8] (combined)  L☉
Metallicity [Fe/H]−0.38±0.06 [9] or +0.17 [10]   dex
Age 912±21 [9] or 9.5 [11]   Myr
A
Mass 1.86±0.02 [7]   M☉
Radius 2.14±0.06 [7]   R☉
Surface gravity (log g)4.05±0.02 [7]   cgs
Temperature 8,050±200 [12]   K
Rotational velocity (v sin i)64±6 [10]  km/s
B
Mass 1.82±0.02 [7]   M☉
Radius 2.34±0.06 [7]   R☉
Surface gravity (log g)3.96±0.02 [7]   cgs
Temperature 7,444±129 [13]   K
Rotational velocity (v sin i)70±6 [10]  km/s
Other designations
9 G. Chamaeleontis [14] , RS Cha, CD−78°342, CPD−78°378, GC  12128, HD  75747, HIP  42794, HR  3524, SAO  256549, WDS 08413-7858CD [15]
Database references
SIMBAD data

HD 75747, also known as HR 3524 or RS Chamaeleontis (RS Cha), is a binary star located in the southern circumpolar constellation Chamaeleon. It has an average apparent magnitude of 6.05, [16] making it barely visible to the naked eye. The system is located relatively close at a distance of 322 light years based on Gaia DR3 parallax measurements [1] but is receding with a somewhat constrained heliocentric radial velocity of 16.1  km/s . [5] It has an absolute magnitude of +1.21. [6]

A light curve for RS Chamaeleontis, plotted from TESS data RSChaLightCurve.png
A light curve for RS Chamaeleontis, plotted from TESS data

HD 75747 was known to be variable since 1960 based on observations by A. W. J. Cousins. [18] The system was first observed as an eclipsing binary in 1967 by astronomers P. A. T. Wild and H. C. Lagerweij. J. [19] Andersen deduced a circular orbit with a period of 1.66 days for the system. [7] Subsequent observations revealed that one of the components as a δ Scuti variable. [20] RS Cha is an Algol-type eclipsing binary ranging from 6.02 to 6.58 or 6.68 within 1.6699 days, depending on the eclipse. [2] This system is part of the η Chamaeleontis association, a group of young stars moving with Eta Cha, and Eta Cha is just eight arc-minutes to the northwest of RS Cha. [21]

Both components have a stellar classification of A8 IV, indicating that both objects are slightly evolved A-type subgiants. RS Cha A and B have masses nearly double of the Sun's and 2.14 - 2.34 times the radius of the Sun. [7] They radiate 17.3 times the luminosity of the Sun [8] from its photosphere at effective temperatures of 8,050  K [12] and 7,444  K respectively, [13] giving the object a white hue. RS Cha was originally thought to be 912 million years old, [9] meaning that both stars were evolving off the main sequence. However, astronomer E. Alecian and colleagues re-examined the age of the system and it turns out that HD 75747 is only 9 million years old, [11] making them pre-main sequence stars. The components rotation periods are synchronous to the orbital period, having projected rotational velocities of 64  km/s and 70  km/s respectively. [10]

Related Research Articles

<span class="mw-page-title-main">Z Chamaeleontis</span> Variable star in the constellation Chamaeleon

Z Chamaeleontis is a dwarf nova variable star system approximately 377 light-years away from the Sun, where two stars orbit each other every 1.78 hours. The system comprises an eclipsing white dwarf and red dwarf and possibly a yet unconfirmed third low-mass substellar companion.

<span class="mw-page-title-main">Zeta Chamaeleontis</span> Variable star in the constellation Chamaeleon

Zeta Chamaeleontis, Latinized from ζ Chamaeleontis, is a star located in the constellation Chamaeleon. Located around 570 light-years distant, it shines with a luminosity approximately 522 times that of the Sun and has a surface temperature of 15,655 K. South African Astronomer A.W.J. Cousins noted it to vary between magnitudes 5.06 and 5.17 in 1960. It was classified as a Beta Cephei variable in the Hipparcos and Tycho Catalogues, with a period of 1.07 days, before being reclassified as a slowly pulsating B star in the 2011 version. It is also an eclipsing binary star, with a period of 2.7 days.

<span class="mw-page-title-main">Eta Chamaeleontis</span> Star in the constellation Chamaeleon

Eta Chamaeleontis, Latinized from η Chamaeleontis, is a star in the constellation Chamaeleon. It has an apparent magnitude of about 5.5, meaning that it is just barely visible to the naked eye. Based upon parallax measurements, this star is located some 325 light-years light years away from the Sun.

HD 39901 is an orange hued star located in the constellation Columba. It is also called HR 2069, which is the star's Bright Star Catalog designation. Eggen (1989) lists it as a member of the old disk population.

<span class="mw-page-title-main">HD 57197</span> Star in the constellation Puppis

HD 57197, also known as M Puppis or HR 2789, is a suspected astrometric binary located in the southern constellation Puppis, the poop deck. It has an apparent magnitude of 5.84, making it faintly visible to the naked eye under ideal conditions. Based on parallax measurements from the Gaia satellite, the system is estimated to be 629 light years away from the Solar System. The value is poorly constrained, but it appears to be receding with a heliocentric radial velocity of 13 km/s. At its current distance, HD 57197's brightness is diminished by 0.3 magnitudes due to interstellar dust. It has an absolute magnitude of -0.43.

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<span class="mw-page-title-main">HD 174387</span> Star in the constellation of Telescopium

HD 174387 is a solitary star in the southern constellation Telescopium. With an apparent magnitude of 5.49, it is faintly visible to the naked eye if viewed under dark skies. Parallax measurements put the object at a distance of 810 light years and it is currently approaching the Solar System with a heliocentric radial velocity of −28.1 km/s.

<span class="mw-page-title-main">TZ Mensae</span> Algol type binary in the constellation Mensa

TZ Mensae is a binary star in the southern circumpolar constellation Mensa. The system has a combined maximum apparent magnitude of 6.19, placing it near the limit for naked eye visibility. Parallax measurements place the system at a distance of 403 light years. The radial velocity is small.

<span class="mw-page-title-main">WZ Columbae</span> Star in the constellation of Columba

WZ Columbae, also known as HD 38170, is a solitary, bluish-white hued star located in the southern constellation Columba, the dove. It has an apparent magnitude of 5.28, allowing it to be faintly visible to the naked eye. Based on parallax measurements from the Gaia spacecraft, the object is about 365 light years distant. It appears to be receding from the Solar System, having a heliocentric radial velocity of 36.3 km/s.

<span class="mw-page-title-main">DR Chamaeleontis</span> Binary star in the constellation Chamaeleon

DR Chamaeleontis, also known as HD 93237, is a star located in the southern circumpolar constellation Chamaeleon. The system has an average apparent magnitude of 5.97, allowing it to be faintly visible to the naked eye. DR Cha is located relatively far at a distance of 1,060 light years based on Gaia DR3 parallax measurements, but is receding with a poorly constrained heliocentric radial velocity of 18 km/s.

<span class="mw-page-title-main">PW Telescopii</span> Α2 CVn variable; Telescopium

PW Telescopii, also known as HD 183806 or simply PW Tel, is a solitary variable star located in the southern constellation Telescopium. It has an average apparent magnitude of 5.58, making it faintly visible to the naked eye. Based on parallax measurements from the Gaia satellite, the star is estimated to be 395 light years distant. It appears to be approaching the Solar System with a heliocentric radial velocity of −10 km/s. The value is somewhat constrained, having an uncertainty of 26%. At its current distance, PW Tel's brightness is diminished by 0.05 magnitudes due to interstellar dust.

<span class="mw-page-title-main">HD 201772</span> Star in the constellation Microscopium

HD 201772, also known as HR 8104, is a yellowish-white hued star located in the southern constellation Microscopium. It has an apparent magnitude of 5.26, making it one of the brighter members of this generally faint constellation. The object is located relatively close at a distance of 111 light-years based on Gaia DR3 parallax measurements but is approaching closer with a heliocentric radial velocity of −41 km/s. At its current distance, HD 201772's brightness is diminished by 0.11 magnitudes due to interstellar dust.

<span class="mw-page-title-main">HD 118285</span> SPB star in the constellation Chamaeleon.

HD 118285, also known as HR 5115, is a variable star located in the southern circumpolar constellation Chamaeleon. DY Chamaeleontis is its variable star designation. It has an average apparent magnitude of 6.32, placing it near the limit for naked eye visibility. The object is located relatively far at a distance of 864 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of 18 km/s. At its current distance, HD 118285's brightness is diminished by 0.58 magnitudes due to interstellar dust.

<span class="mw-page-title-main">HD 168592</span> Star in the constellation of Corona Australis

HD 168592, also designated as HR 6862 or rarely 7 G. Coronae Australis, is a solitary star located in the southern constellation Corona Australis. It is faintly visible to the naked eye as an orange-hued star with an apparent magnitude of 5.07. Gaia DR3 parallax measurements place it at a distance of 490 light years and is currently receding with a heliocentric radial velocity of 18 km/s. At its current distance, HD 168592's brightness is diminished by 0.38 magnitudes due to interstellar dust. It has an absolute magnitude of −0.76.

<span class="mw-page-title-main">HD 187086</span> Astrometric binary and uspected variable star

HD 187086, also known as HR 7537, is a probable astrometric binary located in the southern constellation Telescopium. It has an average apparent magnitude of 5.9, making it faintly visible to the naked eye. The star is located relatively far at a distance of 1,020 light years based on Gaia DR3 parallax measurements but is rapidly drifting closer with a heliocentric radial velocity of −64 km/s. At its current distance, HD 187086's brightness is diminished by 0.27 magnitudes due to interstellar dust. It has an absolute magnitude of −0.8.

<span class="mw-page-title-main">HD 93486</span> Algol variable in the constellation Chamaeleon

HD 93486, also known as HIP 52381, is a binary star located in the southern circumpolar constellation Chamaeleon near the border with Octans. Its variable star designation is RZ Chamaeleontis. It has an apparent magnitude ranging from 8.2 to 9.1, which is below the limit for naked eye visibility. Gaia DR3 parallax measurements place the system 568 light years away, and it is currently receding with a heliocentric radial velocity of 20 km/s. At its current distance, HD 93486's average brightness is diminished by 0.53 magnitudes due to interstellar dust. The system has a combined absolute magnitude of +1.72.

<span class="mw-page-title-main">HD 170873</span> K-type giant; Telescopium

HD 170873, also known as HR 6954 or rarely 19 G. Telescopii, is a solitary orange-hued star located in the southern constellation Telescopium. It has an apparent magnitude of 6.20, placing it near the limit for naked eye visibility. Gaia DR3 parallax measurements imply a distance of 551 light years and it is currently receding with a heliocentric radial velocity of 23.8 km/s. At its current distance, HD 170873's brightness is diminished by 0.39 magnitudes due to interstellar dust, and it has an absolute magnitude of −0.31.

<span class="mw-page-title-main">T Chamaeleontis</span> T Tauri star; Chamaeleon

T Chamaeleontis, also known as HIP 58285, is a T Tauri star located in the southern circumpolar constellation Chamaeleon. It has an apparent magnitude that ranges from 10.05 to 14.50, which is below the limit for naked eye visibility. Gaia DR3 parallax measurements place the object 335 light years away and it is currently receding with a heliocentric radial velocity of 13.8 km/s. At its current distance, T Cha's average brightness is diminished by 0.31 magnitudes due to extinction from interstellar dust. It has an average absolute magnitude of +6.55.

<span class="mw-page-title-main">HD 172991</span> Hot/cold binary; Corona Australis

HD 172991, also known as HR 7031 or rarely 20 G. Coronae Australis, is a binary star located in the southern constellation Corona Australis. It has a combined apparent magnitude of 5.44, making it faintly visible to the naked eye. The system is located relatively far at a distance of 1,220 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of −17.4 km/s. At its current distance HD 172991's brightness is diminished by magnitudes due to interstellar dust and it has an absolute magnitude of −2.56.

<span class="mw-page-title-main">HD 192827</span> Suspected variable; Telescopium

HD 192827, also known as HR 7745 or rarely 83 G. Telescopii, is a solitary red hued star located in the southern constellation Telescopium. It has an apparent magnitude of 6.28, placing it near the limit for naked eye visibility. The object is located relatively far at a distance of 1,320 light years based on Gaia DR3 parallax measurements, but it is approaching with a heliocentric radial velocity of −43.7 km/s. At its current distance, HD 192827's brightness is diminished by 0.19 magnitudes due to interstellar dust and it has an absolute magnitude of −1.07.

References

  1. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia Collaboration) (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics . arXiv: 2208.00211 . doi: 10.1051/0004-6361/202243940 . Gaia DR3 record for this source at VizieR.
  2. 1 2 3 Samus’, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. eISSN   1562-6881. ISSN   1063-7729. S2CID   125853869.
  3. ↑ Jones, D. H. P. (1969). "Spectroscopic Observations of two Eclipsing Binaries". Monthly Notes of the Astronomical Society of South Africa. 28: 5. Bibcode:1969MNSSA..28....5J. ISSN   0024-8266.
  4. 1 2 Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
  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. eISSN   1562-6873. ISSN   1063-7737. S2CID   119231169.
  6. 1 2 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN   1562-6873. ISSN   1063-7737. S2CID   119257644.
  7. 1 2 3 4 5 6 7 8 9 10 11 12 13 Andersen, J. (November 1975). "Spectroscopic observations of eclipsing binaries. I. Description of methods, and results for RS Chamaeleontis and chi 2 Hydrae". Astronomy and Astrophysics. 44: 445–458. Bibcode:1975A&A....44..445A. ISSN   0004-6361.
  8. 1 2 3 4 Clausen, J. V.; Nordstrom, B. (March 1980). "Four-colour photometry of eclipsing binaries. XIa". Astronomy and Astrophysics. 83: 339–347. Bibcode:1980A&A....83..339C. ISSN   0004-6361.
  9. 1 2 3 Kovaleva, D. A. (December 2001). "Age and metallicity estimates for moderate-mass stars in eclipsing binaries". Astronomy Reports. 45 (12): 972–983. Bibcode:2001ARep...45..972K. doi:10.1134/1.1426128. eISSN   1562-6881. ISSN   1063-7729. S2CID   121028634.
  10. 1 2 3 4 Alecian, E.; Catala, C.; Van't Veer-Menneret, C.; Goupil, M.-J.; Balona, L. (14 October 2005). "Pulsations and metallicity of the pre-main sequence eclipsing spectroscopic binary RS Cha". Astronomy & Astrophysics. 442 (3): 993–1002. Bibcode:2005A&A...442..993A. doi: 10.1051/0004-6361:20041906 . eISSN   1432-0746. ISSN   0004-6361.
  11. 1 2 Alecian, E.; Goupil, M.-J.; Lebreton, Y.; Dupret, M.-A.; Catala, C. (11 January 2007). "Calibration of the pre-main sequence RS Chamaleontis binary system". Astronomy & Astrophysics. 465 (1): 241–248. arXiv: astro-ph/0610947 . Bibcode:2007A&A...465..241A. doi: 10.1051/0004-6361:20065822 . eISSN   1432-0746. ISSN   0004-6361.
  12. 1 2 Relyea, L. J.; Kurucz, R. L. (May 1978). "A theoretical analysis of UVBY photometry". The Astrophysical Journal Supplement Series. 37: 45. Bibcode:1978ApJS...37...45R. doi: 10.1086/190517 . eISSN   1538-4365. ISSN   0067-0049.
  13. 1 2 David, Trevor J.; Hillenbrand, Lynne A. (12 May 2015). "The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv: 1501.03154 . Bibcode:2015ApJ...804..146D. doi: 10.1088/0004-637X/804/2/146 . eISSN   1538-4357.
  14. ↑ Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
  15. ↑ "RS Cha". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved January 12, 2023.
  16. ↑ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN   0004-6361.
  17. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  18. ↑ Cousins, A. W. J. (1960). "New Bright Variable Stars". Monthly Notes of the Astronomical Society of South Africa. 19: 56. Bibcode:1960MNSSA..19...56C. ISSN   0024-8266.
  19. ↑ Wild, P. A. T.; Lagerweij, H. C. (1967). "Preliminary Photometric Elements of the Eclipsing Binary System 9 Cha". Monthly Notes of the Astronomical Society of South Africa. 26: 144. Bibcode:1967MNSSA..26..144W. ISSN   0024-8266.
  20. ↑ McInally, C. J.; Austin, R. D. (September 1977). "RS Cha: a delta Scuti Variable". Information Bulletin on Variable Stars. 1334: 1. Bibcode:1977IBVS.1334....1M. ISSN   0374-0676.
  21. ↑ Murphy, Simon J.; Lawson, Warrick A.; Bessell, Michael S. (20 August 2013). "Re-examining the membership and origin of the ϵ Cha association". Monthly Notices of the Royal Astronomical Society. 435 (2): 1325–1349. arXiv: 1305.4177 . Bibcode:2013MNRAS.435.1325M. doi: 10.1093/mnras/stt1375 . eISSN   1365-2966. ISSN   0035-8711.
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