QQ Telescopii

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,^[2] placing it near the limit for naked eye visibility, even under ideal conditions. Gaia DR3 parallax measurements imply a distance of 333 light years^[1] and it is currently receding with a heliocentric radial velocity of 7.8 km/s.^[6] At its current distance, QQ Telescopii's brightness is diminished by two tenths of a magnitude due to interstellar dust^[16] and it has an absolute magnitude of +1.01.^[7]

A light curve for QQ Telescopii, plotted from TESS data^[17]

QQ Telescopii

Location of QQ Telescopii (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Telescopium
Right ascension	19h 39m 41.77938s[1]
Declination	−45° 16′ 42.7871″[1]
Apparent magnitude (V)	6.25[2]
Characteristics
Spectral type	F2 IV[3] or F0 III:[4]
B−V color index	+0.28[2]
Variable type	δ Scuti[5]
Astrometry
Radial velocity (Rv)	7.8±1.5[6] km/s
Proper motion (μ)	RA: −22.160 mas/yr[1] Dec.: +5.375 mas/yr[1]
Parallax (π)	9.8017 ± 0.0327 mas[1]
Distance	333 ± 1 ly (102.0 ± 0.3 pc)
Absolute magnitude (MV)	+1.01[7]
Details
Mass	1.68[8] M☉
Radius	3.19±0.16[9] R☉
Luminosity	26.1±0.2[1] L☉
Surface gravity (log g)	3.73±0.12[10] cgs
Temperature	7,380±136[11] K
Metallicity [Fe/H]	+0.07±0.15[12] dex
Rotational velocity (v sin i)	45±5[13] km/s
Age	995+121 −120[1] Myr
Other designations
66 G. Telescopii[14], QQ Tel, CD−45°13354, CPD−45°9764, GC 27167, HD 185139, HIP 96721, HR 7461, SAO 229800[15]
Database references
SIMBAD	data

HD 185139 was discovered to be a δ Scuti variable in 1982 by Debora W. Kurtz along with HR 151 (BG Ceti).^[18] After a few years of subsequent observations, it was given the variable designation QQ Telescopii in 1985.^[19] In 2002, C. Koen and colleagues attempted to identify the pulsation modes of the star.^[13] The brightness of QQ Tel fluctuates by about 0.05 magnitudes in the blue passband within 1.56 hours.^[5]

QQ Telescopii has a stellar classification of F2 IV,^[3] indicating that it is a slightly evolved F-type subgiant. It was previously classified as kA6mF0 III^[20] and A0pSr(CrSi),^[21] indicating that it is either a chemically peculiar Ap star or Am star. However, Renson & Manfroid (2009) considers its chemical peculiarity to be doubtful.^[22] Andersen & Nordstöm (1978) give it a class of F0 III:,^[4] indicating that it is an evolved F-type giant star with uncertainty about the luminosity class. Evolutionary models place it very close to the end of its main sequence life.^[1]

With 1.68 times the mass of the Sun^[8] and an enlarged radius 3.19 times that of the Sun,^[9] QQ Telescopii radiates 26.1 times the luminosity of the Sun^[1] from its photosphere at an effective temperature of 7,380 K,^[11] giving it a yellowish-white hue. It is slightly metal enriched at [Fe/H] = +0.07^[12] but the value is poorly constrained. The star is estimated to be 995 million years old^[1] and it spins modestly with a projected rotational velocity of 45 km/s.^[13]

References

1. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
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. S2CID 118307502.
3. Houk, Nancy (1978). Michigan catalogue of two-dimensional spectral types for the HD stars: Declinations −53° to −40°. Vol. 2. Bibcode:1978mcts.book.....H.
4. Andersen, J.; Nordström, B. (July 1978). "Corrections to Spectral Types of Bright Southern Stars". Bulletin d'Information du Centre de Donnees Stellaires. 15: 39. Bibcode:1978BICDS..15...39A. ISSN 1169-8837.
5. 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.
6. 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.
7. 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.
8. Yang, Zilu; Zhang, Liyun; Meng, Gang; Han, Xianming L.; Misra, Prabhakar; Yang, Jiawei; Pi, Qingfeng (21 December 2022). "Properties of flare events based on light curves from the TESS survey". Astronomy & Astrophysics. 669: A15. Bibcode:2023A&A...669A..15Y. doi:10.1051/0004-6361/202142710. eISSN 1432-0746. ISSN 0004-6361. S2CID 253194905.
9. Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (October 2004). "The angular sizes of dwarf stars and subgiants. Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics. 426 (1): 297–307. arXiv:astro-ph/0404180. Bibcode:2004A&A...426..297K. doi:10.1051/0004-6361:20035930. eISSN 1432-0746. ISSN 0004-6361. S2CID 6077801.
10. Allende Prieto, C.; Lambert, D. L. (December 1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555–562. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A. ISSN 0004-6361. S2CID 13365201.
11. Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. eISSN 1538-3881. hdl:1721.1/124721. S2CID 166227927.
12. Paunzen, E.; Handler, G.; Weiss, W. W.; Nesvacil, N.; Hempel, A.; Romero-Colmenero, E.; Vuthela, F. F.; Reegen, P.; Shobbrook, R. R.; Kilkenny, D. (30 August 2002). "On the Period-Luminosity-Colour-Metallicity relation and the pulsational characteristics of λ Bootis type stars". Astronomy & Astrophysics. 392 (2): 515–528. arXiv:astro-ph/0207494. Bibcode:2002A&A...392..515P. doi:10.1051/0004-6361:20020854. eISSN 1432-0746. ISSN 0004-6361. S2CID 54666586.
13. Koen, C.; Balona, L.; van Wyk, F.; Marang, F.; Paunzen, E. (March 2002). "An attempt to identify the pulsation modes in the δ Scuti star QQ Tel". Monthly Notices of the Royal Astronomical Society. 330 (3): 567–574. Bibcode:2002MNRAS.330..567K. doi:10.1046/j.1365-8711.2002.05089.x. eISSN 1365-2966. ISSN 0035-8711. S2CID 121946206.
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. "V* QQ Tel". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved March 24, 2023.
16. Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society. 472 (4): 3805–3820. arXiv:1709.01160. Bibcode:2017MNRAS.472.3805G. doi:10.1093/mnras/stx2219. eISSN 1365-2966. ISSN 0035-8711. S2CID 118879856.
17. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 29 March 2023.
18. Kurtz, D. W. (1 October 1982). "The δ Scuti variability of three stars with Ap spectral classifications, HR 151, 239 and 7461". Monthly Notices of the Royal Astronomical Society. 200 (3): 503–507. Bibcode:1982MNRAS.200..503K. doi:10.1093/mnras/200.3.503. eISSN 1365-2966. ISSN 0035-8711. S2CID 120991196.
19. Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Perova, N. B. (March 1985). "The 67th Name-List of Variable Stars". Information Bulletin on Variable Stars. 2681: 1. Bibcode:1985IBVS.2681....1K. ISSN 0374-0676.
20. Hoffleit, Dorrit (January 1953). "The spectra and absolute magnitudes of 500 A3 - G2 stars". Annals of Harvard College Observatory. 0119: 1–35. Bibcode:1953AnHar.119....1H.
21. Brandi, E.; Claria, J. J. (October 1973). "Southern peculiar stars with abnormal spectra". Astronomy and Astrophysics Supplement Series. 12: 79. Bibcode:1973A&AS...12...79B. ISSN 0365-0138.
22. Renson, P.; Manfroid, J. (19 March 2009). "Catalogue of Ap, HgMn and Am stars". Astronomy & Astrophysics. 498 (3): 961–966. Bibcode:2009A&A...498..961R. doi:10.1051/0004-6361/200810788. eISSN 1432-0746. ISSN 0004-6361. S2CID 55849045.