HS 0943 + 1404 , a true intermediate polar ⋆
نویسندگان
چکیده
We have identified a new intermediate polar, HS 0943+1404, as part of our ongoing search for cataclysmic variables in the Hamburg Quasar Survey. The orbital and white dwarf spin periods determined from time-resolved photometry and spectroscopy are P orb ≃ 250 min and Pspin = 69.171 ± 0.001 min, respectively. The combination of a large ratio Pspin/P orb ≃ 0.3 and a long orbital period is very unusual compared to the other known intermediate polars. The magnetic moment of the white dwarf is estimated to be µ1 ∼ 10 34 G cm 3 , which is in the typical range of polars. Our extensive photometry shows that HS 0943+1404 enters into deep (∼ 3 mag) low states, which are also a characteristic feature of polars. We therefore suggest that the system is a true " intermediate " polar that will eventually synchronise, that is, a transitional object between intermediate polars and polars. The optical spectrum of HS 0943+1404 also exhibits a number of unusual emission lines, most noticeably N II λ5680, which is likely to reflect enhanced nitrogen abundances in the envelope of the secondary.
منابع مشابه
The periods of the intermediate polar RX J0153.3+7446
We present the first optical photometry of the counterpart to the candidate intermediate polar RX J0153.3+7446. This reveals an optical pulse period of 2333± 5 s. Reanalysis of the previously published ROSAT X-ray data reveals that the true X-ray pulse period is probably 1974± 30 s, rather than the 1414 s previously reported. Given that the previously noted orbital period of the system is 3.94 ...
متن کاملPsr 0943 + 10 : a Bare Strange Star ?
Recent work by Rankin & Deshpande strongly suggests that there exist strong " micro-storms " rotating around the magnetic axis of the 1.1s pulsar PSR 0943+10. Such a feature hints that most probably the large-voltage vacuum gap proposed by Ruderman & Sutherland (RS) does exist in the pulsar polar cap. However, there are severe arguments against the formation of the RS-type gap in pulsars, since...
متن کاملIntranasal immunization with a recombinant outer membrane protein H based Haemorrhagic septicemia vaccine in dairy calves
Haemorrhagic septicemia (HS) is a contagious disease in cattle with high morbidity and mortality rates. HS vaccine in Thailand is an oil-adjuvant formulation, and is difficult to administer. The present study aimed to formulate and evaluate the protection in dairy calves conferred by immunization with an in-house intranasal HS vaccine. The intranasal vaccine was formulated in a total volume of ...
متن کاملPictoris really an intermediate polar ?
We present the results of a long ROSAT HRI observation of the candidate intermediate polar TW Pic. The power spectrum shows no sign of either the previously proposed white dwarf spin period or the proposed binary orbital period (1.996 hr and 6.06 hr respectively). The limits to the X-ray modulation are less than 0.3% in each case. In the absence of a coherent X-ray pulsation, the credentials of...
متن کاملSutton Hotspot: Resolving Ediacaran-cambrian Tectonics and True Polar Wander for Laurentia
Hotspot tracks represent plate motions relative to mantle sources, and paleomagnetic data from magmatic units along those tracks can quantify motions of those mantle anomalies relative to the Earth’s magnetic field and rotational axis. The Ediacaran Period is notable for rapid and large paleomagnetic apparent polar wander (APW) for many continents. Whereas magmatic units attributed to the “Sutt...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2005