Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Demonstration of a novel method for measuring mass-loss rates for
  massive stars   The rate at which massive stars eject mass in stellar winds significantly
influences their evolutionary path. Cosmic rates of nucleosynthesis, explosive
stellar phenomena, and compact object genesis depend on this poorly known facet
of stellar evolution. We employ an unexploited observational technique for
measuring the mass-loss rates of O- and early-B stars. Our approach, which has
no adjustable parameters, uses the principle of pressure equilibrium between
the stellar wind and the ambient interstellar medium for a high-velocity star
generating an infrared bowshock nebula. Results for twenty bowshock-generating
stars show good agreement with two sets of theoretical predictions for O5--O9.5
main-sequence stars, yielding $\dot M=$1.3$\times$10$^{-6}$ to
2$\times$10$^{-9}$ solar masses per year. Although $\dot M$ values derived for
this sample are smaller than theoretical expectations by a factor of about two,
this discrepancy is greatly reduced compared to canonical mass-loss methods.
Bowshock-derived mass-loss rates are factors of ten smaller than
H$\alpha$-based measurements (uncorrected for clumping) for similar stellar
types and are nearly an order of magnitude larger than P$^{4+}$ and some other
UV absorption-line-based diagnostics. Ambient interstellar densities of at
least several cm$^{-3}$ appear to be required for formation of a prominent
infrared bowshock nebula. $\dot M$ measurements for early-B stars are not yet
compelling owing to the small number in our sample and the lack of clear
theoretical predictions in the regime of lower stellar luminosities. These
results may constitute a partial resolution of the extant "weak-wind problem"
for late-O stars. The technique shows promise for determining mass-loss rates
in the weak-wind regime.

31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
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The categories of this paper are: nucl-ex
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The categories of this paper are: cs
3
The categories of this paper are: physics