HM Sagittae

HM Sagittae is an intensively-studied[5] D-type symbiotic nova in the northern constellation of Sagitta. It was discovered by O. D. Dokuchaeva and colleagues in 1975 when it increased in brightness by six magnitudes. The object displays an emission line spectrum similar to a planetary nebula and by 1977 is detected in the radio band.[4] 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.[6]

HM Sagittae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Sagitta
Right ascension 19h 41m 57.080s[1]
Declination +16° 44′ 39.81″[1]
Characteristics
Spectral type M7[2]
Astrometry
Proper motion (μ) RA: −0.443 mas/yr[1]
Dec.: −7.104 mas/yr[1]
Parallax (π)0.9735 ± 0.1033 mas[1]
Distanceapprox. 3,400 ly
(approx. 1,000 pc)
Other designations
HM Sge, Nova Sge 1975,[3] SVS 2183[4]
Database references
SIMBADdata

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 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.[7] By 1983, the infrared emission of the system was shown to vary by 1.5 magnitudes in the K-band with a time scale of ~500 days.[8] High resolution spectral examination of the system in 1984 showed a bipolar outflow of matter with a velocity of 200 km/s.[6] A series of knots extend outward on both sides of the central star to an angular distance of 9 arcseconds.[5] The nebula surrounding the system shows a bi-polar, S-shaped morphology, similar to R Aqr.[9]

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.[6] 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 AU.[10] The giant component is most likely a Mira variable and measurements up to 1989 found a period of 527 days. The compact object is a hot white dwarf with 70% of the mass of the Sun. Winds from both stars are colliding to produce a shock region that is a source of ultraviolet emission.[11] 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.[12]

References
  1. 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. Gaia EDR3 record for this source at VizieR.
  2. 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.
  3. "HM Sge", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-02-09.
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. 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.
  10. 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.
  11. 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.
  12. 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
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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 l981-1982", 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.
  • 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, Dordrecht: D. Reidel Publishing Co., pp. 209–211, Bibcode:1982ASSL...95..209K, doi:10.1007/978-94-009-7834-8_39.
  • 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 Astrononmy 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.
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