HM Sagittae is a dusty-type symbiotic nova in the northern constellation of Sagitta.[8] It was discovered by O. D. Dokuchaeva and colleagues in 1975 when it increased in brightness by six magnitudes (a factor of around 250 brighter).[12] The object displays an emission line spectrum similar to a planetary nebula and was detected in the radio band in 1977.[11] Unlike a classical nova, the optical brightness of this system did not rapidly decrease with time, although it showed some variation. It displays activity in every band of the electromagnetic spectrum from X-ray to radio.[13]
 A light curve for HM Sagittae. The main plot shows 1-year averages of AAVSO visual band data.[1] The inset plot (adapted from Munari and Whitelock[2]) shows near-infrared variability arising from the red giant's pulsations. | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Sagitta |
| Right ascension | 19h 41m 57.080s[3] |
| Declination | +16° 44′ 39.81″[3] |
| Apparent magnitude (V) | 10.99[4] |
| Characteristics | |
| Spectral type | M7[5] |
| Apparent magnitude (pg) | 11.10 to 18[6] |
| B−V color index | 2.38[4] |
| Variable type | NC + M[6] |
| Astrometry | |
| Proper motion (μ) | RA: −0.443 mas/yr[3] Dec.: −7.104 mas/yr[3] |
| Parallax (π) | 0.9735 ± 0.1033 mas[3] |
| Distance | approx. 3,400 ly (approx. 1,000 pc) |
| Details | |
| Red giant | |
| Radius | 540[7] R☉ |
| Luminosity | 5,000[8] L☉ |
| Temperature | 3,000[8] K |
| White dwarf | |
| Radius | 0.08[9] R☉ |
| Luminosity | 9,200[9] L☉ |
| Temperature | 200,000[9] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Observations in the infrared during 1978 showed this to be a very strong source with a spectrum that is consistent with a binary symbiotic system similar to V1016 Cyg. The cooler stellar component is emitting material that is then ionized by a hot component, with the emission spectrum coming from heated dust generated by the cooler star.[14] By 1983, the infrared emission of the system was shown to vary by a factor of 1.5 magnitudes in the K-band with a time scale of about 500 days.[15] High resolution spectral examination of the system in 1984 showed a bipolar outflow of matter with a velocity of 200 km/s.[13] A series of knots extend outward on both sides of the central star to an angular distance of 9 arcseconds.[16] The nebula surrounding the system shows a bipolar, S-shaped morphology, similar to R Aqr.[17]
The features of the system are consistent with a central red giant star being orbited by a compact object that is accreting matter from the giant.[13] The pair have an angular separation of 40±9 mas, with the axis aligned along a position angle of 130°±10°. Their physical separation is estimated at 50 astronomical units.[18] The giant component is most likely a Mira variable and measurements up to 1989 found a period of 527 days.[19] It is surrounded by a dusty shell that is mostly composed of silicates.[8] The compact object is a hot white dwarf with 70% of the mass of the Sun,[19] which is orbited by an accretion disk. The nova-like outburst of 1975 may have been generated by a burst of mass transfer from the giant to the white dwarf during the periastron passage of an eccentric orbit, leading to a thermonuclear outburst.[20]
Winds from both stars are colliding to produce a shock region that is a source of ultraviolet emission.[19] By 1985, a fading of the brightness and an increase in redness were observed, caused by dust obscuration. The hot component may be inhibiting dust formation around the giant except in the shadow region behind the star. This could explain observed individual dust obscuration events.[21]
References
edit- ^ "Download Data", aavso.org, AAVSO, retrieved 1 October 2021.
- ^ Munari, U.; Whitelock, P. A. (March 1989), "Variable dust obscuration in the symbiotic Mira and very slow nova, HM Sge", Monthly Notices of the Royal Astronomical Society, 237: 45–50, Bibcode:1989MNRAS.237P..45M, doi:10.1093/mnras/237.1.45P.
- ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ a b Høg, E.; et al. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355: L27, Bibcode:2000A&A...355L..27H, doi:10.1888/0333750888/2862, ISBN 978-0333750889.
- ^ Mürset, U.; Schmid, H. M. (1999), "Spectral classification of the cool giants in symbiotic systems", Astronomy and Astrophysics Supplement, 137 (3): 473, Bibcode:1999A&AS..137..473M, doi:10.1051/aas:1999105.
- ^ a b Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
- ^ Taranova, O. G.; Shenavrin, V. I. (2000), "Infrared Photometry of the Symbiotic Novae V1016 Cyg and HM Sge in 1978-1999", Astronomy Letters, 26 (9): 600, Bibcode:2000AstL...26..600T, doi:10.1134/1.1307894, S2CID 120096176.
- ^ a b c d Sacuto, S.; Chesneau, O. (January 2009), "On the morphology of the compact dust shell in the symbiotic system HM Sagittae", Astronomy and Astrophysics, 493 (3): 1043–1048, arXiv:0812.1896, Bibcode:2009A&A...493.1043S, doi:10.1051/0004-6361:200810934, S2CID 14886524.
- ^ a b c Schild, H.; Eyres, S. P. S.; Salama, A.; Evans, A. (2001), "ISO observations of symbiotic stars. I. HM Sge", Astronomy and Astrophysics, 378: 146, Bibcode:2001A&A...378..146S, doi:10.1051/0004-6361:20011155.
- ^ "HM Sge", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-02-09.
- ^ a b Feldman, P. A. (October 1977), "The Detection of Radio Emission from the New Optical Emission Variable HM Sagittae", Journal of the Royal Astronomical Society of Canada, 71: 386, Bibcode:1977JRASC..71..386F.
- ^ Dokuchaeva, O. D. (October 1976), "A New Emission Object", Information Bulletin on Variable Stars, 1189: 1, Bibcode:1976IBVS.1189....1D.
- ^ a b c Solf, J. (October 1984), "High-resolution observations of bipolar mass flow from the symbiotic star HM Sagittae", Astronomy and Astrophysics, 139: 296–304, Bibcode:1984A&A...139..296S.
- ^ Puetter, R. C.; et al. (July 1978), "Infrared spectra of HM Sagittae and V1016 Cygni", Astrophysical Journal, 223: L93–L95, Bibcode:1978ApJ...223L..93P, doi:10.1086/182736.
- ^ Taranova, O. G.; Iudin, B. F. (January 1983), "V1016 Cygni and HM Sagittae : binary stellar systems", Astronomy and Astrophysics, 117: 209–214, Bibcode:1983A&A...117..209T.
- ^ Corradi, R. L. M.; et al. (August 1999), "The optical nebulae around the symbiotic Miras He 2-147, HM Sagittae and V1016 Cygni", Astronomy and Astrophysics, 348: 978–989, Bibcode:1999A&A...348..978C.
- ^ Hack, Warren J.; Paresce, Francesco (November 1993), "Imaging the Bipolar Nebula around HM Sagittae", Publications of the Astronomical Society of the Pacific, 105: 1273, Bibcode:1993PASP..105.1273H, doi:10.1086/133307, S2CID 121305970.
- ^ Eyres, S. P. S.; et al. (April 2001), "The Inner Nebula and Central Binary of the Symbiotic Star HM Sagittae", The Astrophysical Journal, 551 (1): 512–519, arXiv:astro-ph/0101189, Bibcode:2001ApJ...551..512E, doi:10.1086/320086, S2CID 119332145.
- ^ a b c Sanad, M. R.; Abdel-Sabour, M. A. (April 2020), "Spectral Behavior of the Symbiotic Nova HM Sge in the Ultraviolet", Revista Mexicana de Astronomía y Astrofísica, 56: 63–69, Bibcode:2020RMxAA..56...63S, doi:10.22201/ia.01851101p.2020.56.01.08.
- ^ Chochol, D.; et al. (February 2004), "Long-term photometry of the symbiotic nova HM Sge", Contributions of the Astronomical Observatory Skalnaté Pleso, 34 (1): 5–19, Bibcode:2004CoSka..34....5C.
- ^ Munari, U.; Whitelock, P. A. (March 1989), "Variable dust obscuration in the symbiotic Mira and very slow nova, HM Sge.", Monthly Notices of the Royal Astronomical Society, 237: 45P–50P, Bibcode:1989MNRAS.237P..45M, doi:10.1093/mnras/237.1.45P.
Further reading
edit- Skulskyy, M.; et al. (December 2019), "Diffuse ionizing radiation in nebular envelopes of symbiotic novae V1016 Cyg and HM Sge", Contributions of the Astronomical Observatory Skalnaté Pleso, 49 (3): 493–502, Bibcode:2019CoSka..49..493S.
- Lee, Hee-Won; Kang, Suna (November 2007), "Raman-scattered O VI λ6825 and the Accretion Disk Emission Model in the Symbiotic Stars V1016 Cygni and HM Sagittae", The Astrophysical Journal, 669 (2): 1156–1166, arXiv:0707.2978, Bibcode:2007ApJ...669.1156L, doi:10.1086/521719, S2CID 15902594.
- Sacuto, S.; et al. (April 2007), "A compact dust shell in the symbiotic system HM Sagittae", Astronomy and Astrophysics, 465 (2): 469–480, arXiv:astro-ph/0702374, Bibcode:2007A&A...465..469S, doi:10.1051/0004-6361:20066642, S2CID 14211288.
- Birriel, J. J. (September 2004), "Raman-Scattered He II at 4851 Å in the Symbiotic Stars HM Sagittae and V1016 Cygni", The Astrophysical Journal, 612 (2): 1136–1139, Bibcode:2004ApJ...612.1136B, doi:10.1086/422835, S2CID 122522365.
- Richards, A. M. S.; et al. (April 1999), "High-resolution radio observations of HM SGE - II. Two decades after outburst", Monthly Notices of the Royal Astronomical Society, 305 (2): 380–398, Bibcode:1999MNRAS.305..380R, doi:10.1046/j.1365-8711.1999.02465.x.
- Formiggini, Liliana; et al. (December 1995), "HM Sagittae: the shocked and photoionized interaction zone of two colliding stellar winds", Monthly Notices of the Royal Astronomical Society, 277 (3): 1071–1079, Bibcode:1995MNRAS.277.1071F, doi:10.1093/mnras/277.3.1071.
- Eyres, S. P. S.; et al. (May 1995), "MERLIN observations of bipolar outflow from HM Sagittae", Monthly Notices of the Royal Astronomical Society, 274 (1): 317–323, Bibcode:1995MNRAS.274..317E, doi:10.1093/mnras/274.1.317.
- Eyres, S. P. S.; et al. (February 1995), "Direct Observations of Bipolar Outflow from HM Sagittae", Astrophysics and Space Science, 224 (1–2): 457–458, Bibcode:1995Ap&SS.224..457E, doi:10.1007/BF00667903, S2CID 122116484.
- Arkhipova, V. P.; et al. (September 1994), "UBV observations of the symbiotic nova HM Sagittae", Astronomy Letters, 20 (5): 623–630, Bibcode:1994AstL...20..623A.
- Yudin, B.; et al. (June 1994), "1978-1993 UBVR-JHKLMN photometry of the very slow nova and symbiotic Mira HM Sagittae. I. The data", Astronomy and Astrophysics Supplement, 105: 169–178, Bibcode:1994A&AS..105..169Y.
- Yudin, B. F. (1994), "IR emission of the symbiotic nova HM Sagittae", Astronomicheskii Zhurnal, 71: 900–909, Bibcode:1994AZh....71..900Y.
- Arkhipova, V. P.; Noskova, R. I. (May 1991), "The spectrophotometry of HM Sagittae in 1984-1989", Pis'ma v Astronomicheskii Zhurnal, 17: 440–452, Bibcode:1991PAZh...17..440A.
- Nussbaumer, H.; Vogel, M. (September 1990), "HM Sagittae : the evolution of a symbiotic nova.", Astronomy and Astrophysics, 236: 117, Bibcode:1990A&A...236..117N.
- de Freitas Pacheco, J. A.; et al. (February 1989), "The Chemical Composition of the Emitting Gas in HM Sagittae", Astrophysical Journal, 337: 520, Bibcode:1989ApJ...337..520D, doi:10.1086/167120.
- Dokuschaeva, O. D.; Kurochkin, N. E. (1988), "HM Sagittae, a protoplanetary disc nebula", Peremennye Zvezdy, 22: 863–865, Bibcode:1988PZ.....22..863D.
- Lorenzetti, D.; et al. (November 1985), "On the IR variability of symbiotic stars : the case of V1016 Cygni, HM Sagittae and V1329 Cygni", Astrophysical Journal, 298: 350–356, Bibcode:1985ApJ...298..350L, doi:10.1086/163616.
- Stauffer, J. R. (May 1984), "Evolution of the optical spectrum of HM Sagittae : 1977-1982", Astrophysical Journal, 280: 695–711, Bibcode:1984ApJ...280..695S, doi:10.1086/162043.
- Kwok, S.; et al. (April 1984), "The radio structure of HM Sagittae", Astrophysical Journal, 279: 188–196, Bibcode:1984ApJ...279..188K, doi:10.1086/161881.
- Purton, C. R.; et al. (December 1983), "The radio history of HM Sagittae", Astronomical Journal, 88: 1825–1831, Bibcode:1983AJ.....88.1825P, doi:10.1086/113474.
- Ciatti, F.; Vittone, A. (June 1983), "HM SGE and V1016 CYG : spectroscopic changes in 1981-1982", Astronomy and Astrophysics, 122: 343–345, Bibcode:1983A&A...122..343C.
- Welty, D. E. (March 1983), "Emission-line profiles for selected planetary nebulae and symbiotic stars V1016 Cygni and HM Sagittae", Publications of the Astronomical Society of the Pacific, 95: 217–228, Bibcode:1983PASP...95..217W, doi:10.1086/131148.
- Feibelman, W. A. (July 1982), "IUE observations of proto-planetary nebulae. I. V1016 Cyg, HM SGE and HBV 475", Astrophysical Journal, 258: 548–561, Bibcode:1982ApJ...258..548F, doi:10.1086/160105.
- Andrillat, Y.; et al. (April 1982), "Visible and/or near infrared spectral variations of v1016 Cygni, HM sagittae and MWC 349", Astrophysics and Space Science, 83 (1–2): 423–435, Bibcode:1982Ap&SS..83..423A, doi:10.1007/BF00648571, S2CID 120408328.
- Taranova, O. G.; Yudin, B. F. (February 1982), "Infrared photometry of HM Sagittae", Soviet Astronomy Letters, 8: 46–48, Bibcode:1982SvAL....8...46T.
- Kwok, S. (1982), "HM Sagittae — A most Remarkable Star", The nature of symbiotic stars; Proceedings of the Seventieth Colloquium, Saint-Michel-l'Observatoire, Alpes-de-Haute-Provence, France, August 26-28, 1981, Astrophysics and Space Science Library, vol. 95, Dordrecht: D. Reidel Publishing Co., pp. 209–211, Bibcode:1982ASSL...95..209K, doi:10.1007/978-94-009-7834-8_39, ISBN 978-94-009-7836-2, S2CID 118347384.
- Willson, L. A. (1982), "X-rays from HM Sagittae", Journal of the American Association of Variable Star Observers, 11: 81–82, Bibcode:1982JAVSO..11...81W.
- Ipatov, A. P.; Yudin, B. F. (October 1981), "Spectrophotometry of HM Sagittae", Soviet Astronomy Letters, 7: 309–311, Bibcode:1981SvAL....7..309I.
- Thronson, H. A.; Harvey, J. M. (September 1981), "Near-infrared spectroscopy of possible precursors to planetary nebulae : HM Sagittae", Astrophysical Journal, 248: 584–590, Bibcode:1981ApJ...248..584T, doi:10.1086/159183.
- Blair, W. P.; et al. (June 1981), "HM Sge : Symbiotic cousin of the RS CVn stars?", Astronomy and Astrophysics, 99: 73–79, Bibcode:1981A&A....99...73B.
- Feibelman, W. A.; et al. (October 1980), "Electron densities for six planetary nebulae and HM SGE derived from the CIII lambda 1907/1909 ratio", Astrophysical Journal, 241: 725–727, Bibcode:1980ApJ...241..725F, doi:10.1086/158383.
- Taranova, O. G.; Yudin, B. F. (June 1980), "Infrared variability of HM SGE and V1016 Cyg", Soviet Astronomy Letters, 6: 273–274, Bibcode:1980SvAL....6..273T.
- Ciatti, F.; et al. (October 1979), "New observations of HM Sge and V1916 Cyg: simultaneous presence of increasing excitation and cool features", Astronomy and Astrophysics, 79: 247–250, Bibcode:1979A&A....79..247C.
- Kwok, S.; Purton, C. R. (April 1979), "HM Sagittae as a young planetary nebula", Astrophysical Journal, 229: 187–195, Bibcode:1979ApJ...229..187K, doi:10.1086/156944.
- Noskova, R. I.; et al. (1979), "New photometric sequence for HM Sge", Peremennye Zvezdy Prilozhenie, 3: 755–758, Bibcode:1979PZP.....3..755N.