Astronomy:DD Microscopii
| Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
|---|---|
| Constellation | Microscopium |
| Right ascension | 21h 00m 06.3576s[2] |
| Declination | −42° 38′ 44.9350″[2] |
| Apparent magnitude (V) | 11.0 - 11.7[3] |
| Characteristics | |
| Spectral type | K2 III[4] or K5/M0 IIIe[5] |
| U−B color index | +0.37[6] |
| B−V color index | +1.57[6] |
| Variable type | Z And[3] |
| Astrometry | |
| Proper motion (μ) | RA: −10.080[2] mas/yr Dec.: −2.035[2] mas/yr |
| Parallax (π) | 0.1072 ± 0.0205[2] mas |
| Distance | 1-2,000[4] pc |
| Orbit[7] | |
| Primary | yellow giant |
| Companion | White dwarf |
| Period (P) | 1,442 d |
| Eccentricity (e) | 0.22 |
| Periastron epoch (T) | 2,445,560 |
| Argument of periapsis (ω) (primary) | 261° |
| Semi-amplitude (K1) (primary) | 4.6 km/s |
| Details | |
| yellow giant | |
| Mass | 1.45[8] M☉ |
| Radius | 103[9] R☉ |
| Surface gravity (log g) | 0.25[8] cgs |
| Temperature | 3,941[8] K |
| Metallicity [Fe/H] | −0.93±0.06[10] dex |
| Rotational velocity (v sin i) | <3[7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
DD Microscopii, also known as CD−43°14304, is a binary star system in the constellation Microscopium. The system has a combined average apparent magnitude around 11,[12] making it readily visible in telescopes but not to the naked eye. It is thought to be at a distance of one or two thousand parsecs,[4] although parallax measurements place the system at a distance of around 30,000 light years.[2]
It is a symbiotic star system composed of an orange giant with a class of either K2 III[4] or K5/M0 IIIe.[5] Both stellar classifications of the primary indicate a red giant, but one has a regular spectrum while the other shows an evolved star with the characteristics of a K5 and M0 giant star plus emission lines in its spectrum. The secondary is a white dwarf in close orbit, ionizing the stellar wind of the larger star.[citation needed] The giant star and white dwarf both take about 4 years to orbit each other.[7]
The primary has an enlarged radius of 103 R☉[9] and an effective temperature of 3,941 K,[8] giving a red hue when viewed through a telescope. DD Microscopii is extremely metal deficient, with an iron abundance only 12% of the Sun,[10] and spins leisurely with a projected rotational velocity lower than 3 km/s.[7] The star system has its origin in the galactic halo of the Milky Way as indicated by the high galactic latitude.[4] DD Microscopii is cataloged as a Z Andromedae variable, a type of symbiotic binary with occasional outbursts. It fluctuates between magnitudes 11.0 and 11.7 over a span of almost 400 days.[13]
References
- ↑ "ASAS-SN Variable Stars Database". ASAS-SN. https://asas-sn.osu.edu/variables/lookup.
- ↑ 2.0 2.1 2.2 2.3 2.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 3.0 3.1 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. doi:10.1134/S1063772917010085. ISSN 1063-7729. Bibcode: 2017ARep...61...80S.
- ↑ 4.0 4.1 4.2 4.3 4.4 Pereira, C.B.; Roig, F. (2009). "High-Resolution Spectroscopic Observations of Four Yellow-Type Symbiotic Stars: CD-43°14304, Hen 3-1213, Hen 3-863, and StHα 176". The Astronomical Journal 137 (1): 118–28. doi:10.1088/0004-6256/137/1/118. Bibcode: 2009AJ....137..118P.
- ↑ 5.0 5.1 Schulte-Ladbeck, R. E. (January 1988). "Near-infrared spectral classification of symbiotic stars.". Astronomy and Astrophysics 189: 97–108. ISSN 0004-6361. Bibcode: 1988A&A...189...97S.
- ↑ 6.0 6.1 Munari, U.; Yudin, B. F.; Taranova, O. G.; Massone, G.; Marang, F.; Roberts, G.; Winkler, H.; Whitelock, P. A. (May 1992). "UBVRI-JHKL photometric catalogue of symbiotic stars.". Astronomy and Astrophysics Supplement Series 93: 383–390. ISSN 0365-0138. Bibcode: 1992A&AS...93..383M.
- ↑ 7.0 7.1 7.2 7.3 Schmid, H. M.; Dumm, T.; Murset, U.; Nussbaumer, H.; Schild, H.; Schmutz, W. (January 1998). "High resolution spectroscopy of symbiotic stars. III. Radial velocity curve for CD--43(deg) 14304". Astronomy and Astrophysics 329: 986–990. ISSN 0004-6361. Bibcode: 1998A&A...329..986S.
- ↑ 8.0 8.1 8.2 8.3 Anders, F. et al. (February 2022). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G = 18.5". Astronomy & Astrophysics 658: A91. doi:10.1051/0004-6361/202142369. ISSN 0004-6361. Bibcode: 2022A&A...658A..91A.
- ↑ 9.0 9.1 Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256. Bibcode: 2019AJ....158..138S.
- ↑ 10.0 10.1 Gałan, Cezary; Mikołajewska, Joanna; Hinkle, Kenneth H.; Joyce, Richard R. (15 December 2016). "Chemical abundance analysis of 13 southern symbiotic giants from high-resolution spectra at ~1.56 μm". Monthly Notices of the Royal Astronomical Society 466 (2): 2194–2201. doi:10.1093/mnras/stw3266. ISSN 0035-8711. Bibcode: 2017MNRAS.466.2194G.
- ↑ "DD Mic". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=DD+Mic.
- ↑ Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (August 2006). "The 78th Name-List of Variable Stars". Information Bulletin on Variable Stars 5721: 1. ISSN 0374-0676. Bibcode: 2006IBVS.5721....1K.
- ↑ Watson, C. L.; Henden, A. A.; Price, A. (May 2006). "The International Variable Star Index (VSX)". Society for Astronomical Sciences Annual Symposium 25: 47. Bibcode: 2006SASS...25...47W.
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