Z Apodis

Not to be confused with Zeta Apodis.

Z Apodis

A visual band light curve for Z Apodis, plotted from ASAS-SN data[1]
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Apus
Right ascension	14^h 06^m 54.82^s[2]
Declination	−71° 22′ 16.7″[2]
Apparent magnitude (V)	10.8 to 12.0[3]
Characteristics
U−B color index	+0.5 - +1.5[4]
B−V color index	+1.5 - +1.75[4]
Variable type	RV Tau?[3]
Astrometry
Proper motion (μ)	RA: −3.841[2] mas/yr Dec.: −1.604[2] mas/yr
Parallax (π)	0.3135 ± 0.0131 mas[2]
Distance	10,400 ± 400 ly (3,200 ± 100 pc)
Details
Mass	3.2[5] M☉
Radius	27.6[2] R☉
Luminosity	405[2] L☉
Surface gravity (log g)	2.12[2] cgs
Temperature	4,579[2] K
Metallicity [Fe/H]	−0.76[5] dex
Age	11[6] Gyr
Other designations
Z Aps, TYC 9252-1914-1, 2MASS J14065484-7122167, AAVSO 1358-70A
Database references
SIMBAD	data

Z Apodis (Z Aps) is a variable star in the constellation of Apus. It has an apparent visual magnitude which varies between 10.8 and 12.8,[3] over a period of 39.37 days.[3] Although described in the General Catalogue of Variable Stars as a cataclysmic variable star, it appears that it is a pulsating variable star,[4] and has been classed as an RV Tauri variable star, type RVa.[3] Other sources classify it is a type II (W Virginis) Cepheid.[7]

Edna B. Florence discovered the variability of Z Apodis by examining photographic plates. The discovery was announced by Henrietta Hill Swope in 1931. Examination of 20 plates taken in 1925 allowed the derivation of a period of 19.5 days, almost exactly half of the currently accepted period. However observations outside of that time window seemed "...too scattered to give any other indication of a period.", so the star was initially classified as an irregular variable.[8]

References

1. "ASAS-SN Variable Stars Database". ASAS-SN Variable Stars Database. ASAS-SN. Retrieved 6 January 2022.
2. 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.
3. Watson, Christopher (4 January 2010). "Z Apodis". The International Variable Star Index. American Association of Variable Star Observers. Retrieved 20 Nov 2022.
4. Marino, B. F.; Walker, W. S. G. (1991). "Z Apodis is a Pulsating - not a Cataclysmic - Variable Star". Information Bulletin on Variable Stars. 3664: 1. Bibcode:1991IBVS.3664....1M.
5. Anders, F.; Khalatyan, A.; Queiroz, A. B. A.; Chiappini, C.; Ardevol, J.; Casamiquela, L.; Figueras, F.; Jimenez-Arranz, O.; Jordi, C.; Monguio, M.; Romero-Gomez, M.; Altamirano, D.; Antoja, T.; Assaad, R.; Cantat-Gaudin, T.; Castro-Ginard, A.; Enke, H.; Girardi, L.; Guiglion, G.; Khan, S.; Luri, X.; Miglio, A.; Minchev, I.; Ramos, P.; Santiago, B. X.; Steinmetz, M. (2022). "VizieR Online Data Catalog: StarHorse2, Gaia EDR3 photo-astrometric distances (Anders+, 2022)". Vizier Online Data Catalog. Bibcode:2022yCat.1354....0A.
6. Fouesneau, M.; Andrae, R.; Dharmawardena, T.; Rybizki, J.; Bailer-Jones, C. A. L.; Demleitner, M. (2022). "Astrophysical parameters from Gaia DR2, 2MASS, and AllWISE". Astronomy and Astrophysics. 662: A125. arXiv:2201.03252. Bibcode:2022A&A...662A.125F. doi:10.1051/0004-6361/202141828. S2CID 245837778.
7. Ripepi, V.; Molinaro, R.; Musella, I.; Marconi, M.; Leccia, S.; Eyer, L. (2019). "Reclassification of Cepheids in the Gaia Data Release 2. Period-luminosity and period-Wesenheit relations in the Gaia passbands". Astronomy and Astrophysics. 625: 625. arXiv:1810.10486. Bibcode:2019A&A...625A..14R. doi:10.1051/0004-6361/201834506. S2CID 119338608.
8. Swope, Henrietta H. (June 1931). "New Variable Stars in Centaurus and Circinus". Harvard College Observatory Bulletin. 883: 23–30. Bibcode:1931BHarO.883...23S. Retrieved 15 November 2024.